TW543288B - Flexible surface wave device and communication device - Google Patents

Abstract

The present discloses a flexible surface wave device providing improved balance in terms of conversion function of balun and the communication device using it. All vertically coupled resonator type inter-digital transducers (IDT) 2, 1, 3 with balun conversion function are installed along flexible surface wave propagation direction on piezoelectric substrate 8. In at least one of the IDTs 2, 1, 3, e.g. inside each electrode finger 21, 22 of IDT 2, cross weighing electrode finger 22a applied with cross weighing concerning the electrode finger 21 around the opposite area of IDT 1 are installed.

Description

543288 A7 ____B7 V. Description of the Invention (Technical Field) The present invention relates to a surface acoustic wave device used for a filter having an unbalanced-balanced conversion function, and a communication device using the same. [Knowledge technology] In recent years, technological advances in miniaturization and weight reduction of communication devices such as mobile phones have been amazing. As a filter used in such a communication device, as the use bandwidth becomes higher, a surface acoustic wave device capable of miniaturization is used. In addition, in order to reduce the number and size of each component in the communication device, development of components with multiple functions has also been carried out. Against such a background, in the surface acoustic wave filter used in the RF band of a mobile phone, a solution called a balun having a balanced-unbalanced conversion function has been widely used in recent years. It can be used mainly around GSM (Global System for Mobile Communications). Several patents related to a surface acoustic wave filter including such a balanced-unbalanced conversion function have been filed. As a surface acoustic wave filter having an input impedance and an output impedance that are approximately equal, and having a balanced-unbalanced conversion function, a structure shown in Fig. 67 is known. The surface acoustic wave device shown in FIG. 67 is provided with a comb-shaped electrode portion (so-called curtain electrode portion, Inter-Dlgltal Transducei *, hereinafter referred to as IDT) 101 on the piezoelectric substrate 100, and is located on the left and right sides of the IDT 101 (along the elastic surface). The transmission direction of the wave) is configured with IDT102 and IDT103, which have balanced-unbalanced conversion function, 3IDT type longitudinal coupling type resonator type, 3 wood paper scales applicable to China National Standard (CNS) A4 specifications (210 X 297 mm) ) -------------------- Order * ------- 1 (Please read the notes on the back before filling this page) 543288 A7 B7 V. Invention Description (/) of a surface acoustic wave device. In the aforementioned surface acoustic wave device, a reflector 104 and a reflector 105 are further respectively disposed so as to sandwich the IDTs 102, 101, and 103 from the left and right, and set the terminals 106 and 107 as balanced signal terminals. Set terminal 108 as the unbalanced signal terminal. Further, as another surface acoustic wave device having a balanced-unbalanced conversion function that causes an input impedance and an output impedance to differ by four times, for example, a structure described in Japanese Patent Laid-Open Publication No. Hei 10-117123 can be cited. As shown in FIG. 68, the surface acoustic wave device described in the aforementioned publication includes a first surface acoustic wave filter U1 on a piezoelectric substrate, and a phase of an output signal that differs from the first surface acoustic wave filter 111 by 180 degrees. Two elastic surface wave chirpers m. Also, in FIG. 6S, the description of the piezoelectric element is omitted. Therefore, while the front surface has the function of a server, it can perform balanced-unbalanced conversion work &. The first-surface acoustic wave filter 111 is a 3idt longitudinally-coupled narrow-vibrator-type surface acoustic wave filter 118, and a relative ° longitudinally coupled resonator-type surface acoustic wave filter _ m, sandwiched along the elasticity- Symmetrical lines in the direction of the _Li Rei Li __ continued vibrating surface acoustic wave filter I24, cascaded, that is, two sections of vertical construction test. Longitudinal affinity resonator-type surface acoustic wave m ^ m, at the center of the nmn qi (along the surface acoustic wave transmission direction) are respectively configured 〇τη4, U5 'and reflectors 116, U7 are respectively arranged to further Side clamp these 1DT114, ⑴, 1Q5. _Combined Resonator Bullet -------------------- Order · -------- (Please read the precautions on the back before filling this page) t The paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 543288 A7 _________B7______ V. Description of the invention) / The SAW filter 124 is also equipped with IDT120, 121 on the left and right of IDT119 in the center, and The reflectors 122 and 123 are arranged so that the IDT120, 119, and 121 are clamped from the left and right sides. The second surface acoustic wave filter 112 is a longitudinally coupled resonator-type surface acoustic wave filter 128 that is the same as the 3IDT-type longitudinally coupled resonator-type surface acoustic wave filter 124, and is provided with a longitudinal coupling that is relatively 3IDT-type. A longitudinally coupled resonator-type surface acoustic wave filter 127 of a resonator-type surface acoustic wave filter Π8 and an IDT 133 whose phase is reversed (ie, about 180 °) is reversed in the direction of the central IDT 103, and two segments are longitudinally connected. One terminal 129, 130 of the first surface acoustic wave filter 111 and the second surface acoustic wave filter II2 are electrically connected in parallel, the other terminals 131, 132 are electrically connected in series, and the terminal 108 is connected with the terminals connected in parallel. The terminals connected in series constitute the terminals 106, 107. In a surface acoustic wave device having a balanced-unbalanced conversion function, the transmission characteristics in the transmission band between the unbalanced terminal 108 and each of the balanced terminals 106 and 107 require equal amplitude characteristics and phase characteristics. 180 degrees from each other. These characteristics are called amplitude balance and phase balance, respectively. Considering that the surface acoustic wave device having the aforementioned balanced-unbalanced conversion function is a 3-terminal element, for example, when the unbalanced input terminal is terminal 1 and each balanced output terminal is terminal 2 and terminal 3, the amplitude balance is And the phase balance is defined by the following formula: Amplitude balance = | AAB A = | 201og (S21) | — | 201og (S31) |… Equation (1) Phase balance = = B, B = | ZS21- zS31 |… Eq. (2) ^ Paper size is suitable for Chinese National Standard (CNS) A4 specification (21〇χ 297 mm) — '~. -------- Order · -------- (Please read the precautions on the back before filling in this page} 543288 A7 ___ B7____ V. Description of the invention (^) Moreover, S21 represents the transmission coefficient from terminal 1 to terminal 2, and S31 represents the transmission coefficient from terminal 1 to terminal 3 In the ideal case, such a degree of balance has an amplitude balance of 0 dB and a phase balance of 180 degrees in the passband of the filter characteristics of the surface acoustic wave device. [Problems to be Solved by the Invention] However, as described above, In a surface acoustic wave device having balanced signal terminals, there is a problem that the balance between the balanced signal terminals deteriorates. There are several reasons for the deterioration of the balance. As one of them, the distance between the electrode finger connected to the balanced signal terminal 106 and the signal electrode finger of the IDT 102 (109 in FIG. 67) and the distance between the electrode finger connected to the balanced signal terminal 107 and the balanced signal terminal 107 The distance between the electrode finger and the signal electrode finger of IDT103 (110 in Fig. 67) differs by 0.5 times the wavelength determined by the electrode finger pitch. Therefore, the total electricity of the electrode finger connected to each balanced signal terminal 106, 107 is The disadvantage is that the conversion efficiency between the electric signal and the surface acoustic wave is different due to the difference in capacity. As a result, the deterioration of the balance is affected. Therefore, it is determined that the balanced signal terminal 107 of FIG. 67 is grounded as shown in FIG. The amplitude characteristics corresponding to the frequency output from the terminal 106 and the amplitude characteristics corresponding to the frequency output from the balanced signal terminal 107 when the balanced signal terminal 106 of FIG. 67 is grounded as shown in FIG. 71 are shown in FIG. 69 as their The difference between the aforementioned amplitude characteristics. The difference between the two amplitude characteristics is large, and this difference affects the deterioration of the balance. Also, as shown in FIG. 68, the cascaded surface acoustic wave In the device, the polarities of the electrode fingers of two adjacent IDTs facing each other are right and left. 6 The paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ----- ------- Φ clothing -------- order --------- line · (Please read the precautions on the back before filling this page) 543288 A7 _______B7__ 5. Description of the invention ( <), therefore, the problem of deterioration in balance arises. That is, IDT113 is on the adjacent IDT114, 115 and everywhere (125 in Figure 68), and the outermost electrode fingers of the adjacent IDT113, 114, 115 are all ground electrode fingers. In contrast, IDT133 is on the Adjacent IDT134, 135 and adjacent places (126 in Fig. 68) are signal electrode fingers and ground electrodes. When such a combination of polarities in the outermost electrode fingers of adjacent IDTs changes', the frequency and amplitude level of the resonance mode shown in Fig. 72 change due to the conversion between the electrical signal and the surface acoustic wave. As shown in FIG. 68, two longitudinally coupled resonator-type surface acoustic wave filters having different combinations of the outermost electrode fingers in the adjacent IDTs are combined to form a balanced-unbalanced conversion function. In this case, the deviation of the resonance mode becomes a cause of deterioration in the balance between the balanced signal terminals. This phenomenon occurs even when a longitudinally coupled resonator-type surface acoustic wave filter is used to form a surface acoustic wave device having a balanced-unbalanced conversion function as shown in FIG. 73. This causes the deterioration of the balance between the balanced signal terminals. The object of the present invention is to provide elasticity with balanced-to-unbalanced conversion function with good balance between the balanced signal terminals by correcting the aforementioned difference between the balanced signal terminals as a factor that deteriorates the balance between the balanced signal terminals. Surface wave device and communication device using the same. [Means to solve the problem] In order to solve the above-mentioned problem, the surface acoustic wave device of the present invention is provided with _____ 7 I-scale scales applicable to the Chinese National Standard (CNS) A4 standard (21Q χ 297 public love) '' '- ------------------- Order --------- line (please read the notes on the back before filling this page) 543288 A7 _____ B7-5 2. Description of the invention (^) At least one surface acoustic wave filter having at least two comb-shaped electrode portions formed along a surface acoustic wave transmission direction on a piezoelectric substrate, and an input signal for the aforementioned surface acoustic wave filter The terminal and the output signal terminal are characterized in that at least one of the input signal terminal and the output signal terminal is connected to the balanced signal terminal, and the electrode fingers of at least a part of the surface acoustic wave filter are weighted. According to the above configuration, since at least a part of the electrode fingers of the surface acoustic wave filter having at least two 1DTs are weighted, the balance of each characteristic (at least one of amplitude balance, phase balance, and transmission characteristics) between the balanced signal terminals can be adjusted. Therefore, the balance of each characteristic can be improved. In the above-mentioned surface acoustic wave device, it is preferable that weighting is applied to a part of the electrode fingers in order to improve at least one of amplitude balance and phase balance between the pair of balanced signal terminals. In the above surface acoustic wave device, the weighting may be performed on at least one of the adjacent IDTs of the surface acoustic wave filter from a plurality of electrode fingers starting from an outermost electrode finger adjacent to the IDT. In the above-mentioned surface acoustic wave device, the weighting may be performed on at least one of the adjacent IDTs of the surface acoustic wave filter, and a plurality of electrode fingers located near the outermost electrode fingers of the IDT adjacent to each other. In the above-mentioned surface acoustic wave device, the weighting may be applied to at least one of the IDTs of the surface acoustic wave filters adjacent to each other, from the outermost electrode adjacent to the IDT to the transmission direction of the surface acoustic wave of the IDT. The electrode finger within the range of 1/2 is implemented. In the above-mentioned surface acoustic wave device, the aforementioned weighting can apply the Chinese National Standard (CNS) A4 specification (210 X 297 mm) to the aforementioned elastic 8 paper sizes ---------------- ---- Order --------- Line · (Please read the notes on the back before filling this page) 543288 A7 ---------- B7___ V. Description of the invention (^) Surface The outermost electrode fingers of the IDT adjacent to each other in at least one of the IDTs where the wave filters are adjacent to each other are implemented. In the above-mentioned surface acoustic wave device, the electrode fingers adjacent to the adjacent IDT of the surface acoustic wave filter are a ground electrode finger and a signal electrode finger respectively, and the foregoing is performed on at least one of the ground electrode finger and the signal electrode finger. Weighted. In the above surface acoustic wave device, the weighted electrode fingers may be signal electrode fingers of the surface acoustic wave filter. In the surface acoustic wave device described above, the weighting may be performed on the electrode fingers of the IDT connected to the balanced signal terminal of the surface acoustic wave filter. In the above-mentioned surface acoustic wave device, the surface acoustic wave filter has at least one IDT phase-inverted relative to other IDTs, and the weighting may be performed on the electrode fingers of the phase-reversed IDT. In the above-mentioned surface acoustic wave device, the weighting may be a thinning weight. In the above-mentioned surface acoustic wave device, it is preferable to provide a virtual electrode on the opposite bus bar opposite to the bus bar to which the thinning-weighted electrode finger is connected. . In the above-mentioned surface acoustic wave device, a ground connection portion may be provided between the ground electrode fingers of the IDT adjacent to each other through the dummy electrode. In the above-mentioned surface acoustic wave device, the weighting may be a weighting in which the crossing width of the electrode fingers is different from the crossing width of other electrode fingers. In the above surface acoustic wave device, the aforementioned cross-width weighting is preferably applied to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) on a 9-wood paper scale -------------- ------ Order --------- line (please read the precautions on the back before filling this page) 543288 B7 V. Description of the invention ((f) Approximately the center of the cross direction. In the above In the surface acoustic wave device, an electrode finger that is different from the cross-width-weighted electrode fe is cross-weighted, and a virtual electrode formed by bending is provided so as to be opposite to the two cross-width-weighted electrode fingers. In the above surface acoustic wave device, the cross-width-weighted electrode finger is an outermost electrode finger of one of the adjacent IDTs, and a dummy electrode is provided on the other IDT so as to be in phase with the cross-width-weighted electrode finger. iiscji 矣 In the above surface acoustic wave device, the virtual electrode may be grounded. In the above-mentioned 5 early surface wave device, the above-mentioned addition may be to make the duty of the electrode fingers (duty) and other electrodes Refers to different duty weights In the above surface acoustic wave device, the surface acoustic wave filter has at least three IDTs, and each of the foregoing weightings is applied to at least one of the adjacent IDTs, and the weightings may be different from each other. In the device, the surface acoustic wave filter is provided in two, and each of the surface acoustic wave filters is implemented with any of the above-mentioned weightings, and the weightings may be different. The wave filter has at least three comb-shaped electrode portions adjacent to each other. In at least one of the comb-shaped electrode portions adjacent to each other, the outermost region of the comb-shaped electrode portions adjacent to each other is different from the outermost electrode finger. The weighting of several electrode fingers of the cross electrode is performed, and at least one of different comb electrode portions adjacent to each other is thinned and weighted at the outermost electrode fingers of the comb electrode portions adjacent to each other. The paper size applies the Chinese National Standard (CNS) A4 specification (21 × 297 mm) -------------------- Order --------- Line (please read the back first Please fill in this page again for attention) 543288 A7 ____B7___ _ V. Description of the invention (/) In the above-mentioned place where the thinning weight is applied, there is a virtual electrode connected to the opposite bus bar. The opposite bus bar is related to the above thinning. The weighted electrode fingers are opposite to each other. In the above-mentioned surface acoustic wave device, at least one of the comb-shaped electrode portions where one of the surface acoustic wave filters is adjacent to each other may be provided. "Combine electrodes that are" cross-weighted by a plurality of electrode fingers that are different from the outermost electrode fingers in the outermost region of the comb-shaped electrode portions adjacent to each other "and are adjacent to each other in the other surface acoustic wave filter In at least one of the parts, the outermost electrode fingers adjacent to each other of the comb-shaped electrode parts are thinned and weighted. At the same time, the thinned weights are provided with a dummy electrode connected to the opposite bus bar. The opposite bus bar is opposite to the bus bar connected to the thinned electrode fingers. In the above-mentioned surface acoustic wave device, two of the surface acoustic wave filters are provided, and at least one of the adjacent IDTs of one surface acoustic wave filter is opposed to the outermost area in the outermost area adjacent to the IDT. A plurality of electrode fingers having different electrode fingers are weighted crosswise. At least one of the adjacent IDTs of the other surface acoustic wave filter is thinned and weighted at the outermost electrode finger adjacent to the IDT. A dummy electrode connected to the opposite bus bar opposite to the bus bar connected to the thinned weighted electrode finger is provided at the foregoing thinning weighting place. In the above surface acoustic wave device, the surface acoustic wave filter may be provided with a balanced signal input-balanced signal output filter function. In the above-mentioned surface acoustic wave device, the aforementioned surface acoustic wave filter may be set to have a balanced signal input-unbalanced signal output filter function. 11 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) " -------- Order --------- line (please read the precautions on the back before filling this page) 543288 A7 ______B7_____ 5. Description of the invention (iD) or unbalanced signal input-balance Signal output filter function. In the above-mentioned surface acoustic wave device, at least one of the aforementioned IDTs is divided into two parts in the cross width direction. In the above-mentioned surface acoustic wave device, the pair of balanced signal terminals are connected to the comb-shaped electrodes of two poles in an IDT, respectively. In the above surface acoustic wave device, at least one of the aforementioned IDTs is divided into two parts in the propagation direction of the surface acoustic wave. In the surface acoustic wave device described above, the pair of balanced signal terminals has an electrically neutral point connected to ground. In the above-mentioned surface acoustic wave device, the two surface acoustic wave filters may be provided as two's with a balanced signal input-balanced signal output filter function. In the above-mentioned surface acoustic wave device, the aforementioned surface acoustic wave filter is two 'set so that the phase of the input signal with respect to the output signal differs by about 180 degrees'. Each of the aforementioned surface acoustic wave filters is provided with a balanced signal input-unbalance. Signal output filter function or unbalanced signal input-balanced signal output filter function. In the above surface acoustic wave device, the surface acoustic wave filter is further cascaded on the side of the unbalanced signal terminal. In the above-mentioned surface acoustic wave device, the surface acoustic wave filter is a vertical pot type resonant surface wave type 1 surface acoustic wave filter; In the above surface acoustic wave device, the longitudinally coupled resonator-type surface acoustic wave filter has an odd number of IDTs. In the above-mentioned surface acoustic wave device, the aforementioned longitudinally coupled resonator-type elastic 12-coat paper size applies the Zhongguanjia Standard (CNS) A4 297 public love) — '' a -------- ^ ----- ---- (Please read the precautions on the back before filling this page) 543288 A7 ____B7___ V. Description of the Invention ((Ί) The surface wave filter has 3 IDTs. In the above surface acoustic wave device, the aforementioned longitudinally coupled resonator The total number of electrode fingers of at least one IDT of the surface acoustic wave filter is even. In the surface acoustic wave device described above, at least three of the longitudinally coupled resonator-type surface acoustic wave filters have at least three IDTs. The total number of IDT electrode fingers connected to the balanced signal terminals is an even number. In the above-mentioned surface acoustic wave device, among the three or more IDTs of the longitudinally coupled resonator-type surface acoustic wave filter, at least The total number of IDT electrode fingers in the central portion is an even number. In the above-mentioned surface acoustic wave device, in the surface acoustic wave filter, at least one surface acoustic wave resonator is connected to at least one of serial or parallel. Surface acoustic wave device The SAW filter is cascaded with two or more SAW filter units. In order to solve the aforementioned problem, another SAW device of the present invention is characterized by having a plurality of electrodes on a piezoelectric substrate. The input comb-type electrode portion of the finger and the output comb-type electrode portion having a plurality of electrode fingers are provided along the propagation direction of the surface acoustic wave so as to form a longitudinally coupled resonator type. The outermost electrode finger of each of the electrode fingers of at least one of the output comb-shaped electrode portions has a weighted electrode finger that is weighted. In the surface acoustic wave device described above, the input IDT and the output IDT One side is for balance, and it is better to have a weighted electrode finger on at least one of the IDTs on the balance side. In the aforementioned surface acoustic wave device, it may have a paper size of 13 $ and apply the Chinese National Standard (CNS) A4 specification (210 x 297 Mm) '---------------------- T --------- phase (please read the notes on the back before filling this page) 543288 A7 ___B7 _ 5. Description of the invention (lu unbalanced- According to the above-mentioned configuration, by providing weighted electrode fingers on each of the electrode fingers of at least one of the input 1DT and the output IDT, it is possible to adjust the characteristics (amplitude balance) between the output signals, especially the output signals for balancing. , Phase balance, and transmission characteristics), so that the balance of each characteristic can be improved. In the above-mentioned surface acoustic wave device, it is preferable that the weighted electrode fingers are provided in one IDT from the next to the outermost electrode finger to all of them. The electrode finger is within a range of 1/2. In the surface acoustic wave device described above, the weighted electrode finger is preferably set shorter than other electrode fingers. In the above-mentioned surface acoustic wave device, at least one of the input IDT and the output IDT includes two or more outermost electrode fingers positioned opposite to the other IDT to form a continuous ground electrode finger. According to the above configuration, each of the electrode fingers includes two or more outermost electrode fingers facing each other to form a continuous ground electrode finger. Thereby, a simple configuration can reliably be used as each output signal for balancing. The phase difference is set around 180 °. In the above-mentioned surface acoustic wave device, the weighted electrode finger is set to control an electric field-free portion formed between adjacent ones of the ground electrode fingers which are at least one of the input electrode IDT and the output IDT. the size of. In the above-mentioned surface acoustic wave device, the input IDT or output IDT is used for balancing, and in the two IDTs for balancing, the size of the electric field-free portion is set to be substantially the same. Set the weighted electrode finger according to the above configuration, in order to control the electric field freely. 14 Wood paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 male 3) ---------------- ---- Order · -------- Thread (please read the notes on the back before filling this page) 543288 A7 _____ B7_ V. Description of the invention (1>) The size of the part is best used for balance In both IDTs, by making the size of the electric field-free portion substantially the same, it is possible to adjust the balance of the conversion of the electrical energy from the elastic energy in the IDTs, particularly in the output IDT, and therefore, the balance can be improved. In the above-mentioned surface acoustic wave device, the first balancing electrode finger which is grounded toward the weighted electrode finger is formed to extend to the length of the weighted electrode finger. According to the above configuration, the electrodeless finger portion formed by the short weighted electrode finger can be covered to a certain extent by the first balancing electrode finger. Therefore, the balance caused by the electrodeless finger portion can be avoided. Sexual degradation. In the above-mentioned surface acoustic wave device, the second balanced electrode finger which is grounded is formed at a position different from the weighted electrode finger, and the length of the weighted electrode finger is overlapped, and the second balanced electrode finger is provided and folded into a Weighted electrodes refer to virtual electrodes formed opposite each other. According to the above configuration, by providing the dummy electrode, it is possible to maintain good balance and further improve the transmission characteristics. In order to solve the aforementioned problem, the communication device of the present invention is characterized by using any one of the aforementioned surface acoustic wave devices. According to the aforementioned configuration, the use of a surface acoustic wave device including excellent balance can improve the performance of the aforementioned configuration b. [Brief description of the drawing] Fig. 1 'It is a surface acoustic wave mounting 15 wood paper scale according to the first embodiment of the present invention. The paper size is applicable to Chinese National Standard (CNS) A4i grid (210 X 297 public love) "'- --- --------------------. I ------- (Please read the notes on the back before filling this page) 543288 A7 ____B7___________ V. DESCRIPTION OF THE INVENTION (The structure of the main part of the invention. FIG. 2 is a schematic diagram showing the structure of the main part of the surface acoustic wave device of the first comparative example. FIG. 3 is the elasticity of a modification of the first embodiment of the present invention Figure 4 shows the structure of the main part of the surface wave device. Figure 4 shows the structure of the main part of the weighted area in the surface acoustic wave device of the first embodiment. Figure 5 shows the amplitude balance of the surface acoustic wave device. FIG. 6 is a graph showing the phase balance (phase balance) of the aforementioned surface acoustic wave device. FIG. 7 is a graph showing the amplitude balance of the surface acoustic wave device of the first comparative example. (Amplitude balance). Fig. 8 shows the bomb of the first comparative example. FIG. 9 is a diagram showing the phase balance (phase balance) of a surface acoustic wave device. FIG. 9 is a structural diagram of a main part of a surface acoustic wave device according to another modification of the first embodiment of the present invention. FIG. 10 is a first view of the present invention. A structural diagram of a main part of a surface acoustic wave device according to another modification of the embodiment. FIG. 11 is a structural diagram of a main part of a surface acoustic wave device according to another modification of the first embodiment of the present invention. The main part of a surface acoustic wave device according to yet another modification of the first embodiment is shown in the structure of the first embodiment. Fig. 13 'is an elastic table according to another modification of the first embodiment of the present invention. A4 specifications (210, 297 public love 1 one " " -------------------- Order --------- line (please read the back first Please pay attention to this page and fill in this page again) 543288 A7 B7 — V. Description of the invention (I,) The structure of the main part of the surface wave device. Fig. 14 shows another modification of the surface acoustic wave device of the first embodiment of the present invention. The structure of the main part. Fig. 15 shows another modification of the first embodiment of the present invention. FIG. 16 is a structural diagram of a main part of a surface acoustic wave device according to still another modification of the first embodiment of the present invention. FIG. 11 is a further structural diagram of a first embodiment of the present invention. A structural diagram of a main part of a surface acoustic wave device according to a modification. FIG. 18 is a structural diagram of a main part of a surface acoustic wave device according to another modification of the first embodiment of the present invention. FIG. 19 is a diagram of a first embodiment of the present invention. A structural diagram of a main part of a surface acoustic wave device according to another modification. Fig. 20 is a structural diagram of a main part of an elastic surface wave device according to still another modification of the first embodiment of the present invention. Fig. 21 is a structural diagram of a main part of a surface acoustic wave device according to still another modification of the first embodiment of the present invention. Fig. 22 is a structural diagram of a main part of an elastic surface wave device according to still another modification of the first embodiment of the present invention. Fig. 23 is a structural diagram of a main part of an elastic surface wave device according to still another modification of the first embodiment of the present invention. Fig. 24 is a structural diagram of a main part of a surface acoustic wave device according to a second embodiment of the present invention. Fig. 25 is a graph showing the amplitude balance (amplitude balance) of the aforementioned surface acoustic wave device. 17 X. Paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) -------------------- Order -------- -Line (please read the precautions on the back before filling this page) 543288 A7 _______B7____ 5. Description of the invention (ft) Figure 26 is a graph showing the phase balance (phase balance) of the aforementioned surface acoustic wave device. Fig. 27 is a graph showing the transmission characteristics of the surface acoustic wave device of the first embodiment. Fig. 28 is a graph showing the transmission characteristics of the surface acoustic wave device of the second embodiment. Fig. 29 is a structural diagram of a main part of a surface acoustic wave device according to a third embodiment of the present invention. Fig. 30 is a graph showing the amplitude balance (amplitude balance) of the elastic surface wave device according to the third embodiment and the second comparative example. Fig. 31 is a graph showing the phase balance (phase balance) of the surface acoustic wave device of the third embodiment and the second comparative example. Fig. 32 is a structural diagram of a main part of a surface acoustic wave device according to a second comparative example of the present invention. Fig. 33 is a structural diagram of a main part of a surface acoustic wave device according to a fourth embodiment of the present invention. Fig. 34 is a graph showing the amplitude balance (amplitude balance) of the surface acoustic wave device according to the fourth embodiment and the second comparative example. Fig. 35 is a structural diagram showing the main part of the deterioration of balance in the second conventional example. Fig. 36 is a diagram showing the configuration of main parts for improving the balance in the fourth embodiment. Fig. 37 is a structural diagram of a main part of a surface acoustic wave device according to a modification of the fourth embodiment of the present invention. 18 _ Applicable to paper size of China National Standard (CNS) A4 (210 x 297 ^ 11 • -------------------- Order ------- -Line Γ Qing first read the no sound on the back of tt? Matters then fill out this page} 543288 A7 ---- -B7 ___ V. Description of Invention

I Fig. 38 'is a configuration diagram of main parts for showing improvement of balance in a modification of the fourth embodiment. Fig. 39 'is a structural diagram of a main part of an elastic surface wave device according to another modification of the fourth embodiment of the present invention. Fig. 40 'is a configuration diagram of main parts for showing improvement of balance in another modification of the fourth embodiment. Fig. 41 'is a structural diagram of a main part of a surface acoustic wave device according to still another modification of the fourth embodiment of the present invention. I 42 'is a structural diagram of a main part of a surface acoustic wave device according to a fifth embodiment of the present invention. Fig. 43 'is a graph showing the amplitude balance (amplitude balance) of the elastic surface wave device according to the fifth embodiment and the third comparative example. Fig. 44 'is a structural diagram of a main part of a surface acoustic wave device according to the third comparative example. Fig. 45 is a diagram showing the configuration of the main part of the deterioration of balance in the third comparative example. Fig. 46 is a diagram showing the configuration of main parts for improving the balance in the fifth embodiment. Fig. 47 is a structural diagram of a main part of a surface acoustic wave device according to a sixth embodiment of the present invention. Fig. 48 is an enlarged structural view of a main part of a surface acoustic wave device according to a sixth embodiment of the present invention. Fig. 4 is a graph showing the amplitude balance (amplitude balance) of the elastic surface wave device according to the sixth embodiment and the fourth comparative example. 19 (Please read the notes on the back before filling this page) Feng ----- Order --------- Line. Applicable to China National Standard (CNS) A4 (210 X 297 mm) ) 543288 A7 _______B7____ 5. Description of the invention (/ (^) Fig. 50 'is a structural diagram of the main part of the surface acoustic wave device of the fourth comparative example. Fig. 51' is a diagram showing the surface acoustic wave device of the sixth embodiment. A rhyme diagram showing a change in the amplitude balance degree (amplitude balance) with a change in the crossing width. Fig. 52 'is a diagram showing a main part of a surface acoustic wave device according to a modification of the sixth embodiment of the present invention. Fig. 53' Fig. 54 'is a structural diagram of a main part of a surface acoustic wave device according to another modification of the sixth embodiment of the present invention. Fig. 55 'It is a configuration diagram of a main part of a surface acoustic wave device according to a modification of the seventh embodiment of the present invention. FIG. 56 shows the amplitude balance (amplitude balance) of the surface acoustic wave device of the seventh embodiment and the second comparative example. ) Graph. FIG. 57 is a graph showing phase balance of the surface acoustic wave device of the seventh embodiment and the second comparative example. FIG. 58 is a diagram of a surface acoustic wave device according to a modification of the seventh embodiment of the present invention. Fig. 59 is a structural diagram of a main part of a surface acoustic wave device according to another modification of the seventh embodiment of the present invention. Fig. 60 is a diagram showing another modification and the first embodiment of the fourth embodiment. A graph of the amplitude balance (amplitude balance) of the surface acoustic wave device of the two comparative examples. 20 Private paper standards are applicable to China National Standard (CNS) A4 (21〇X 297 mm) " '------ -------------- Order --------- Line · (Please read the notes on the back before filling this page) 543288 A7 ________B7 ___ V. Description of the invention (7) Fig. 61 is a graph showing the phase balance of a surface acoustic wave device according to another modification of the fourth embodiment and the second comparative example. Fig. 62 is a view showing the main characteristics of the surface acoustic wave device according to the eighth embodiment of the present invention. Fig. 63 shows the eighth embodiment and the second comparison. A graph showing the amplitude balance (amplitude balance) of the surface acoustic wave device of FIG. 64 is a graph showing the phase balance of the surface acoustic wave device according to the eighth embodiment and the second comparative example. Fig. 66 is a block diagram of a main part of a communication device of the present invention. Fig. 67 is a diagram of a main part of a surface acoustic wave device of the first conventional example. 68 is a configuration diagram of a main part of a surface acoustic wave device according to a second conventional example. FIG. 69 is a graph showing differences in insertion loss between conventional balanced signal terminals. Fig. 70 is a graph showing a surface acoustic wave device having a different insertion loss between the aforementioned conventional balanced signal terminals. Fig. 71 is a graph showing the other surface acoustic wave device showing the difference in insertion loss between the conventional balanced signal terminals. Figures 72 (a) and (b) are diagrams illustrating the resonance mode in a surface acoustic wave device. (A) is a graph showing the frequency relationship of the resonance mode, and (b) is a summary of the effective current distribution in the resonance mode. Composition chart and its corresponding current 21 Wood paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) -------- ^ --------- ^ (please first (Please read the notes on the back and fill in this page) 543288 A7 B7 5. The distribution curve of the invention description. Structure 73 is the main part of the surface acoustic wave device of the third conventional example (please read the precautions on the back before filling this page). [Description of symbols] 1 to 3, 25, 40, 41, 133 to 135, 203a, 204 to 206, 1303, 1304, 1307, 1308, 1503, 1504, 1901 to 1903, 2001 to 2006 10 D (comb-shaped electrode section) 4,202b, 202c, 203b, 203c, 207,208 Reflectors 5,209 to 211, 801, 802, 1101, 1102 Input terminals for unbalance 6, 7,209,803, 1003, 1905 Output terminals for balance 8 Piezo substrate 9 No electric field section 1 l, 22, 32, 204a, 205a, 206a Signal electrode fingers 12, 21, 31, 31b, 204b, 205b, 206b Ground electrode fingers 13, 23, 33 Bus bar 14, 34 Bus bar 21a, 25a, 31a, 1901b Dummy electrode 22a cross Weighted electrode fingers 201, 118, 127, 1918, 1920, 2007, 2008 SAW filters 202,203 SAW resonators 213, 214 Narrow pitch electrode fingers 1301, 1302, 1501, 1502 Transmission signal lines 3100 Communicator 22 Wood paper scale Applicable to China National Standard (CNS) A4 specification (210 X 297 mm) 543288 A7 B7 V. Description of invention (y) 3101 Antenna 3102 Antenna common part / RFTop filter 3103 Amplifier 3104 Rx Interstage filter 3105, 3170 Mixer 3106 IstIF filter 3108 2ndIF filter 3111 lst + 2nd Synthesizer 3112 Temperature compensated quartz oscillator 3113 Frequency divider 3114 Local filter 3121 TxIF filter 3122 Mixer 3123 Tx interstage filter 3124 Amplifier 3125 Coupler 3126 Insulator 3127 Automatic output control ------ -------------- Order --------- Line (Please read the precautions on the back before filling this page) [Implementation Mode of the Invention] The following is based on Figure 1 to Figure 65 to describe various embodiments of the present invention. (First Embodiment) As shown in FIG. 1, the surface acoustic wave device according to the first embodiment of the present invention is applicable to Chinese papers (CNS) A4 (210 X 297 mm). 543288 A7 __ B7_____ 5. DESCRIPTION OF THE INVENTION (1) It has an unbalanced-balanced conversion function and a filter function. The piezoelectric substrate 8 has an input IDT1 and outputs arranged on both sides (along the surface acoustic wave transmission direction) of the output. Use IDT2, 3, followed by reflectors 4 arranged on their outer sides. Moreover, the aforementioned input and output can be converted to each other. That is, the output IDT2, 3 is arranged so as to sandwich the input IDT1 therebetween. Further, each reflector 4 is configured to reflect the transmitted surface acoustic wave with IDT2, IDT1, and IDT3 sandwiched between them. The aforementioned piezoelectric substrate 8 is, for example, 40 ± 5. YcutX transmits LiTa03 composition. IDT1, 2, and 3 have two electrode fingers including a band-shaped base end portion (bus bar) and a plurality of mutually extending parallel to each other from one side portion of the base end portion in an orthogonal direction. The spaced-apart electrode fingers are provided in a state of being interleaved with each other, so that the side portions of the electrode fingers of the electrode fingers face each other. In these IDTs 1, 2, and 3, a signal can be inputted by setting the parent fork width of the length and width of each electrode finger, the distance between adjacent electrode fingers, and the relative length indicating the interleaved state of the mutual electrode fingers. Conversion characteristics and passband settings. In the first embodiment, the number of electrode fingers of IDT 1 is set to 39, and the number of electrode fingers of IDT 2 and 3 is set to 23. The aforementioned electrode fingers, bus bars, and reflectors 4 are formed by, for example, an aluminum (A1) electrode (foil) formed on the piezoelectric substrate 8 by a photolithography method or the like. Furthermore, the first embodiment is to input unbalanced signals and output balanced signals. In the input IDT1, each signal electrode finger 11 connected to the unbalanced input terminal 5 and each ground electrode finger 12 connected to the ground are connected. , 24 I-scale is applicable to China National Standard (CNS) A4 specification (210 X 297 male H ^ a '" -------------------- Order --- ------ ^ (Please read the precautions on the back before filling in this page) A7 543288 5. The invention description (yj) is set up in a staggered state as described above. Moreover, the IDT1 mentioned above is based on an elastic surface. The outermost electrode fingers at both ends of the wave transmission direction are respectively set as ground electrode fingers. The above-mentioned outermost electrode fingers are located at positions opposite to one of the outermost electrode fingers of IDT 2 and 3, respectively. On the other hand, in the IDT 2, the “each ground electrode finger 21” and the signal electrode finger 22 ”on the output terminal 6 for balancing are provided in a state staggered with each other as described above. Further,“ the ground electrode fingers 21 are connected to The bus bar 23 is arranged with respect to each signal electrode finger of the input IDT1. The 11-connected bus bars 13 are substantially linear. In IDT2, the outermost electrode fingers of the electrode fingers at both ends in the transmission direction of the surface acoustic wave are ground electrode fingers 21 ° In IDT3 The ground electrode fingers 31 and the signal electrode fingers 32 ′ connected to the output terminal 7 for balancing are arranged in a staggered state as described above. The bus bars 33 connected to the ground electrode fingers 31 are arranged so The bus bar 13 connected to each of the signal electrode fingers 11 of the IDT1 for input is substantially linear. The bus bar 14 of each ground electrode finger 12 of the IDT1 is set to the bus of each signal electrode finger 22 of the IDT2. The bars 24 and the bus bars 34 of the signal electrode fingers 32 of IDT3 are respectively linear. Also, in the first embodiment, the output IDTs 2 and 3 are arranged to be mutually reversed in structure. That is, in IDT2, From the side close to IDT1, starting from the ground electrode finger, the signal electrode finger and the ground electrode finger are alternately set. On the other hand, in IDT3, from the side close to IDT1, from the signal electrode 25. The paper standard applies to Chinese national standards. CNS) A4 size (210 X 297 mm) -------------------- Order --------- line (Please read the precautions on the back first (Fill in this page again) 543288 A7 ____B7__ 5. Description of the invention (W ") Fingers are alternately provided with ground electrode fingers and signal electrode fingers. According to this, in this first embodiment, since the system is set between IDT2, 3 The amplitude difference is 0 and the phase difference is 180 °. Therefore, a balanced-unbalanced conversion function can be exhibited. In addition, in the first embodiment, the outermost electrode fingers of IDT3 are thinned out at a position adjacent to IDT1 and IDT3. A grounded dummy electrode 31a is formed at the position where the thinned weighted electrode fingers are applied. As a result, in IDT3 near IDT1 and IDT3, the ground electrode is in a state of two consecutive arrays like the dummy electrode 31a and the ground electrode finger 31b. In addition, in the first embodiment, among the signal electrode fingers 22 in the output IDT2, the signal electrode fingers 22 next to the ground electrode fingers 21 that are near the input IDT1 (outermost electrode fingers) are located next to each other. , Set the cross-weighted electrode finger 22a. In the aforementioned cross-weighted electrode finger 22a, the length of the cross-weighted electrode finger 22a is about one-half of the length of the other signal electrode fingers 22, that is, the cross-weighting is adjusted to adjust the cross width. In addition, in order to fill the space created by the short cross-weighted electrode fingers 22a, a band-shaped dummy electrode (first balanced electrode finger) is formed as a bias electrode finger extending from the grounded bus bar 23. 21a. The imaginary electrode 21a extends toward the top end portion of the cross-weighted electrode finger 22a at substantially equal intervals with respect to the ground electrode fingers 21 adjacent to each other at equal intervals. The operation and effect of the first embodiment will be described below. First, as a comparison, FIG. 2 shows a schematic configuration diagram of each IDT of a surface acoustic wave device having a balanced-unbalanced conversion function of the first comparative example in which the aforementioned thinning weighting and cross-weighting are not implemented. Composition of the first comparative example '26 Wood paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) -------------------- Order- ------- Line · (Please read the precautions on the back before filling out this page) 543288 A7 __B7___ V. Description of the invention (/) The ground electrodes are adjacent to each other adjacent to IDT1 and IDT40. Between IDT1 and IDT41, the signal electrode and the ground electrode are side by side. As described above, between IDT1 and IDT40, there is an electric field-free portion 9 that has not been converted between electrical and surface acoustic waves. In contrast, between IDT1 and IDT41, electrical signals (signals) and surface acoustic waves are converted. . Therefore, the frequencies and amplitude levels of the signals output from the balanced output terminals 6 and 7 are different, and the phase is not reversed by 180 degrees at all. As a result, the balance between the balanced signal terminals is deteriorated. In the first embodiment, first, as shown in FIG. 3, the electrode fingers adjacent to IDT1 and IDT41 of the signal electrode and the ground electrode shown in the first comparative example are thinned and weighted. Dummy electrodes 31a are formed at the positions of the weighted electrode fingers. That is, in IDT3 near IDT1 and IDT3, two ground electrode fingers are placed side by side. As a result, the difference in conversion efficiency between the electrical signals between the IDT1 and IDT3 and between the IDT1 and IDT40 and the surface acoustic wave is corrected, and an elastic surface with an improved balance between the balanced signal terminals 6, 7 is obtained.波 装置。 Wave device. Further, by forming the dummy electrode 31a, an increase in the loss caused by the surface acoustic wave being converted into a large wave is prevented, and a surface acoustic wave device having a good insertion loss in the frequency band is obtained. Further, the dummy electrode 31a may be used as a floating electrode without being grounded, but the floating electrode becomes a cause of deterioration in the balance between the balanced signal terminals 6, 7, so it is better to be grounded. However, in the configuration of FIG. 3, by performing the thinning weighting, the IDT1 and IDT3 side-by-side sides of the non-electric field portion 9 are larger than the IDT1 and IDT40 side-by-side. As a result, a sufficient degree of balance between the balanced signal terminals 6, 7 has not been obtained. Due to the 27 wood paper size, the Chinese National Standard (CNS) A4 specification (210 X 297 mm) is applicable -------------------- Order -------- -Line (please read the notes on the back before filling this page) A7 543288 _ B7_______ V. Description of the invention (τΐ) As shown in Figure 4, set the IDT1 and IDT2 side-by-side signal electrode fingers 22 to implement The cross-width-weighted cross-weighted electrode finger 22a 'is provided with a dummy electrode 21a. As a result, the sizes of the electric field-free portions 9, 9 in the boundary portion XI between IDT1 and IDT1 and the boundary portion X2 between IDT1 and IDT3 are substantially the same as each other, thereby further improving the balance between the balanced signal terminals. Surface acoustic wave device. Further, by forming the dummy electrode 21a, an increase in the loss caused by the surface acoustic wave being converted into a large wave is prevented, and a surface acoustic wave device having a good insertion loss in the frequency band is obtained. Such grounded virtual electrodes 21a, 31a form an electric field-free portion 9 between the ground electrode fingers 21, 31 adjacent to each other, and can control the formation area (capacitance of each of the electric field-free portions 9) as described later. The size of the formation area) The cross-weighting described above is effective because the electric field-free portion can be adjusted by applying less weight to the signal electrode, but it is of course possible to weight the ground electrode. In the first embodiment, the weighting is implemented by the electrode fingers adjacent to the input IDT1 and the output IDT2, 3, and the second electrode finger from the electrode finger. However, it can also be used with IDT. Any part of it. However, due to the difference in polarities between the adjacent electrode fingers of the IDT, the resonance mode (resonance mode of C in FIG. 72) located at the highest frequency side of the pass band has a greater influence. As shown in FIG. 72 (b), Adjacent to IDT, the current distribution is relatively large. Therefore, as shown in FIG. 4, it is 28 to implement from the neighborhood of IDT1 and 2 to 1/2 of the length a of the surface acoustic wave in the transmission direction of IDT2. The paper size applies to the Chinese National Standard (CNS) A4 specification (21G X 297 public love) ^ '-------------------- Order · ------ --Line (please read the precautions on the back before filling this page) 543288 A7 _____B7__ V. Description of Invention (/)) Valid. In the first embodiment, the cross-width weighting is performed by setting the cross-weighted electrode fingers 22a that make the signal electrode fingers 22 short to approximately the center. However, the amount of cross-width weighting can be adjusted as necessary. For example, weighting the cross width of the signal electrode finger 22 on the IDT1 side by about 1/4, and even weighting the cross width of the signal signal finger 22 on the next side by about 1/4, the same effect can be obtained.

FIG. 5 shows the amplitude balance between the balanced signal terminals 6, 7 corresponding to the frequencies in the configuration of the first embodiment, and FIG. 6 shows the phase balance. For comparison, FIG. 7 shows the amplitude balance between the balanced signal terminals corresponding to the frequencies in the configuration of the first comparative example shown in FIG. 2, and FIG. 8 shows the phase balance. The frequency range of the pass band of the filter for EGSM transmission is 880MHz ~ 915MHz. The amplitude balance between the balanced signal terminals 6, 7 in this range corresponding to the frequency is 1.6dB ~ + in the first comparative example. 1.5dB (deviation 3.ldB, if the deviation is small, the amplitude balance is good), in contrast, in the first embodiment, it is -0.7dB to + 1.2dB (deviation 1.9dB), which is improved by about 1.2 dB. In the first comparative example, the phase balance between the balanced signal terminals 6, 7 is 172 degrees to 189 (a deviation of 17 degrees, and if the deviation is small, the phase balance is good). In contrast, in this first implementation, In the example, 178 degrees to 184 degrees (a deviation of 6 degrees) improved by about 1.1 degrees. In the first embodiment described above, a longitudinally coupled resonator-type surface acoustic wave filter is used to adapt the 29-M gas-tap scale with balanced-unbalanced conversion work to the national standard (Cns) a4 specification. (210 X 297 mm) -------------------- Order --------- line (Please read the precautions on the back before filling this page ) Α7 Β7 5. Compared with the surface acoustic wave device of the invention, the surface acoustic wave device of the invention can obtain the & right, according to this, and the conventional elastic surface with improved elasticity _ ^ between the signal terminals 6, 7 Balance Degree In the first embodiment, although the structure of the resonator-type elastic diaphragm with three IDT oscillators is called vertically, the parallel surface wave of the present invention uses balanced signal terminals 6,7. The elastic surface of the bombardment surface wave furnace has the same effect. Regardless of the configuration of the surface H, it is possible to use a longitudinally-coupled resonator type with 5 idt elastic surface-to-unbalance type conversion function (surface-level terminal, guard, unbalanced signal terminal 403) ) 'Using this type of vocational-resonance flip-flop surface acoustic wave filter with three or more IDTs, or using a closed-resonance resonator-type elastic surface with two self-resonators, Lai Long_cheng, green ㈣ this effect_. Of course, 'not only the acid 1 «combination II, 性, and the wave device, but even the SAW device using the transverse elasticity of the wave _ wave according to the concept and the type of surface acoustic wave filter, can also get the same Effect. In the first embodiment, although a surface acoustic wave device having a balanced-unbalanced conversion function has been described, even if, for example, FIG. 10 (the balanced signal terminal 501 and the balanced signal terminal 502 are paired and balanced, The signal terminal 503 is paired with the balanced signal terminal 504) and the balanced signal input-balanced signal shown in the figure (the balanced signal terminal 601 is paired with the balanced signal terminal 602, the balanced signal terminal 603 is paired with the balanced signal terminal 604) The same effect can be obtained in the output surface acoustic wave device. 30 (Please read the precautions on the back before filling in this page) -------- Order * -------- Applicable for paper size " ^ Home Standard (CNS) A4 Specification (210 X 297 mm) 543288 A7 B7 V. Explanation of the invention (/) In the first embodiment, although a longitudinally coupled resonator-type surface acoustic wave filter is used, a balanced-unbalanced type is constructed. The surface acoustic wave device with a conversion function is described as an example, but the present invention is not limited to this configuration. All surface acoustic wave devices with a balanced-unbalanced conversion function can obtain an effect. For example, as shown in FIG. 12, balanced signal terminals 701 and 702 (703 are unbalanced signal terminals) are connected to comb-shaped electrodes of two poles of an IDT in a longitudinally coupled resonator-type surface acoustic wave filter, respectively. The configuration of the grounded electrical neutral point; and, as shown in FIG. 13, any IDT is divided in the cross width direction to change the impedance (801, 802 are balanced signal terminals, and 803 are unbalanced signal terminals). ; And, as shown in FIG. 14, the structure is divided in the transmission direction of the surface acoustic wave, and balanced signal terminals 901 and 902 are connected to each of the divided comb-shaped electrodes (903 is an unbalanced signal terminal). To the effect of the present invention. At this time, as shown in FIG. 15, by connecting the unbalanced signal terminals 1003 to the comb-shaped electrodes in other directions in the left and right IDTs, it is possible to obtain an elastic surface that further improves the attenuation outside the passband. Wave device (1001, 1002 are balanced signal terminals). In addition, even if a plurality of longitudinally coupled resonator-type surface acoustic wave filters are combined, the structure of a surface acoustic wave device having a balanced-unbalanced conversion function can obtain the effects of the present invention. For example, as shown in FIG. 16, the phase of the input signal and the output signal of the longitudinally coupled resonator-type surface acoustic wave filter 1105 is about 180 degrees relative to the longitudinally coupled resonator-type surface acoustic wave filter Π04. And, will connect -------- Order --------- IAW. (Please read the notes on the back before filling this page)

543288 A7 B7 ------------ ^ " ------ V. Description of the invention (> G) IDT connected to balanced signal terminals 1101 and 1102 will be connected in series and will be connected In the configuration of a surface acoustic wave device having IDTs connected in parallel to an unbalanced signal terminal 1103 and having a balanced-unbalanced conversion function; and, as shown in FIG. 17, in the configuration of FIG. 16, a vertical The structure of a coupled resonator-type surface acoustic wave filter; as shown in FIG. 18, the effect of the present invention can be obtained by weighting the structure of FIG. 68. As mentioned earlier, in the structure of the stepwise cascaded longitudinal resonant resonant type early surface wave filter, not only the balance between the balanced signal terminals is improved, but also the amount of attenuation outside the passband is obtained. Large surface acoustic wave device. At this time, as shown in FIG. 19, the respective 1DTs 1303 and 130 are reversed to each other so that the electrical signals of the transmission signal lines 1301 and 1302 of the two longitudinally coupled resonator-type surface acoustic wave filters are connected in cascade, respectively. The phase difference is about 180 degrees. Similarly, the IDTs 1307 and 1308 are reversed to each other so that the phases of the electrical signals of the signal lines 1305 and 1306 are about 180 degrees. Based on this, the balance between the signal terminals is further improved. The surface acoustic wave device of the balance. Further, as shown in FIG. 20, even if a configuration of a longitudinally coupled resonator-type surface acoustic wave filter 1401 is further cascaded to the surface acoustic wave device of FIG. 12, the effect of the present invention can be obtained. In this configuration, not only the balance between the balanced signal terminals is improved, but also a surface acoustic wave device having a large attenuation outside the pass band is obtained. At this time, as shown in FIG. 21, the IDTs 1503 and 1504 are reversed to each other so that the phases of the electrical signals transmitted to the respective signal lines 1501 and 1502 are about 180 degrees from each other. Improved the elasticity of the balance between the balanced signal terminals. 32 Wood paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm)------------------- --- Order .-------- f Please read the notes on the back before filling in this page} 543288 A7 V. Description of the invention (> /) Surface wave device. In addition, in the case of cascading two or more longitudinally coupled resonator-type surface acoustic wave filters, it is not necessary to use a longitudinally coupled resonator-type elastic surface wave filter of the same configuration in particular. Adjust the cross width when impedance, or if you want to increase the attenuation outside the band, make the logarithm of IDT and the center distance between adjacent idt, the center distance between IDT and reflector different, etc. The design of the surface wave filter may be different. Moreover, in the first embodiment, any longitudinally coupled resonator-type elastic surface gastric wave filter makes the total number of electrode fingers of each IDT be an odd number, but it may also be made an even number, in particular, As shown in FIG. 22, even if the total number of electrode fingers of the IDT further located at the center of the three IDTs and further connected to the balanced signal terminals is an even number, the effect of the present invention can also be obtained. In this case, Compared with the center of the longitudinally coupled resonator-type surface acoustic wave filter, the left-right symmetry is improved, and the number of electrode fingers connected to the balanced signal terminals becomes equal. Therefore, the balance between the balanced signal terminals is further improved. Balanced surface acoustic wave device. Further, as shown in FIG. 23, the present invention can be obtained by a configuration in which the surface acoustic wave resonators 1601 and 1602 are connected in series with a configuration in which a surface acoustic wave resonator is not connected in parallel or a configuration in which both are connected. Effect. With this configuration, not only the balance between the balanced signal terminals is improved ', but also a surface acoustic wave device having a large amount of attenuation near the pass band is obtained. 33 National Standard for Paper and Paper Sizes (cns) a4 (210 X 297 mm) " ^ 一 -------- Order --------- ^ ^ __ w— (Please read the first Please fill in this page again for attention) 543288 A7 _ B7__ V. Description of Invention (jl) (Second Embodiment) The second embodiment will be described with reference to FIGS. 24 to 28. Also, in this second embodiment, for Components having the same functions as those of the surface acoustic wave device shown in FIG. 1 are denoted by the same component numbers, and descriptions thereof are omitted. In the surface acoustic wave device of the second embodiment, as a weighting method, as shown in FIG. 24 In this case, tandem weighting is used to replace the thinning weight and cross weighting on the cross width in the first embodiment. That is, IDT25 is set to replace IDT2 described in the first embodiment. In IDT25, a cross-weighting electrode is provided. Finger 22a also shortens the cross-weighted electrode finger 21a (next) ground electrode finger 21 on the inside of the cross-weighted electrode finger 22a to replace the aforementioned dummy electrode 21a of IDT2. For further steps, set it apart from the aforementioned two (Ie suspended state) virtual electrode (second 2 [S scale power (Finger) 25a. The aforementioned dummy electrode 25a has the same width as the cross-weighted electrode finger 22a, and extends approximately parallel to the cross-weighted electrode finger 22a and the next signal electrode finger 22, and then passes through the cross-weighted electrode finger 22a. The top end portion and the top end portion of the cross-weighted electrode finger 21b are bent between the cross-weighted electrode finger 21b and the outermost ground electrode finger 21 to form electrode fingers that extend substantially parallel to them. With regard to the elasticity of such IDT25 The surface wave device measures the amplitude balance and phase balance in the vicinity of the pass band. The results are shown in Fig. 25 and Fig. 26. From these results, the frequencies in the frequency range of the pass band of the EGSM transmission filter are known. A balanced signal terminal between the 34 --------------------- order --------- line (Please read the precautions on the back before filling (This page) Applicable to China National Standard (CNS) A4 size (210 x 297 mm) 543288. 5. Description of the invention The amplitude balance is 10.7dB ~ + 1.2dB (deviation 1.9dB), which is the same as the first implementation. The example is the same, but the phase between the balanced signal terminals is flat. The degree is 177 degrees to 182 degrees (deviation of 5 degrees), which is an improvement of 1 degree from the first embodiment. Fig. 27 shows the transmission characteristics in the pass band with respect to frequency in the first embodiment. The transmission characteristics in the passband with respect to frequency in the second embodiment are shown in 28. If the two are compared, in the first embodiment, ripple A occurs in the passband (see FIG. 27), but the second In the embodiment, the aforementioned ripple A (see FIG. 28) does not occur, and a surface acoustic wave device having a deviation in the pass band smaller than that in the first embodiment is obtained. As described above, by implementing the tandem weighting of the cross-width weighting, the surface acoustic wave device that further improves the balance between the balanced signal terminals and the deviation in the frequency band is obtained. In addition, in the second embodiment, compared with the first embodiment described above, the occurrence of ripples is suppressed in transmission characteristics, and the transmission characteristics are more excellent. (Third Embodiment) A third embodiment of the present invention will be described with reference to Figs. 29 to 32. The structure of the first embodiment of the present invention is shown in FIG. 29. In the third embodiment, a PCS reception filter will be described as an example. In the surface acoustic wave device according to the third embodiment, on the piezoelectric substrate 200, a 3IDT longitudinally coupled resonator-type surface acoustic wave filter 201 and each elastic body connected in series with the surface acoustic wave filter 201 The surface wave resonators 202 and 203 are formed of an aluminum (A1) electrode (foil) formed by a photolithography method or the like. Examples of the material of the piezoelectric substrate 200 include 40 ± 5. 35 The paper size is applicable to China National Standard (CNS) A4 (210 X 297 public love) " " " " --- ------------.------- Order * -------- (Please read the precautions on the back before filling this page) 543288 A7 _______B7_______ V. Description of the invention

YcutX transmits UTa03. Such a surface acoustic wave filter 201 is substantially the same as that shown in FIG. 10 described above. In the surface acoustic wave filter 201, each IDT 204, 206 is formed as a center, so that the IDT 205 (in the direction of surface acoustic wave transmission) is sandwiched from the left and right to become a balanced signal terminal side. Further, on the two outer sides of each of the IDTs 204 and 206 (along the surface acoustic wave transmission direction), respective reflectors 207 and 208 reflecting the surface acoustic waves from the aforementioned IDTs 204 to 206 are formed. That is, each IDT and reflector are provided on the surface acoustic wave transmission path so that the width direction of each electrode finger is along the surface acoustic wave transmission direction. Furthermore, in the surface acoustic wave filter 201, it can be seen from FIG. 29 that, as in the foregoing, IDT204 and IDT205 are adjacent to each other and the vicinity thereof, and IDT205 and IDT206 are adjacent to each other and the vicinity thereof. The electrode fingers (narrow-pitch electrode fingers) are set smaller than the other parts of the aforementioned IDTs (at 213 and 214 in FIG. 29). In the above surface acoustic wave device, each of the terminals 210 and 211 is a balanced signal terminal, and the terminal 209 is an unbalanced signal terminal. Accordingly, IDT204 and IDT206 become unbalanced signal sides, and each has signal electrode finger 204a and ground electrode finger 204b, signal electrode finger 206a and ground electrode finger 206b. On the other hand, the IDT 205 is on the balanced signal terminal side and has respective signal electrode fingers 205a and 205b. Accordingly, the third embodiment is an example in which the configuration of the electrically neutral point without ground is weighted. Each surface acoustic wave resonator 202, 203 is connected in series through a signal line 212 between the unbalanced signal terminal 209 and each IDT 204, 206. Fortunately, the paper size applies the Chinese National Standard (CNS) A4 (210 X 297 mm) -------------------- Order ------- --Line (please read the precautions on the back before filling this page) 543288 A7 ____B7_ 5. Description of the Invention (歹 f) The sexual surface wave resonator 202 has IDT202a and each reflection sandwiching it along the transmission direction of the surface acoustic wave器 202b, 202c. The surface acoustic wave resonator 203 includes an IDT 203a and respective reflectors 203b and 203c sandwiching the surface acoustic wave in the propagation direction of the surface acoustic wave. A characteristic point of the third embodiment is that IDT205 is adjacent to IDT206, and weighting is performed on electrode fingers 219 of IDT206 at opposite sides in the transmission direction of the surface acoustic wave. In the third embodiment, as the thinning weight described above, thinning weights are applied to the electrode fingers of IDT 206 adjacent to (closest to) IDT 205 in the signal electrode fingers 206 a of IDT 206. In addition, in the third embodiment, in order to ensure the distance between the electrode fingers and maintain the adjacent IDTs, that is, the distance between the IDTs 205 and 206, the ground electrode fingers 206b are grounded with the ground electrode fingers on the narrower pitch side 206b sets electrode fingers 219 with the same cross width, the same pitch, the same duyt, and the same line width. Accordingly, in the IDT 1206, there are a plurality of, for example, two adjacent ground electrode fingers 206b adjacent to the IDT 205. For the detailed design of the surface acoustic wave filter 201, when the wavelength determined by the pitch of the narrow-pitch electrode fingers is λ Π (at 213 and 214 in FIG. 29), the wavelength determined by the pitch of the other electrode fingers is λ Π When, as follows:

Crossing width W: 60.6 λ II! DT number (in the order of 204, 205, 206): 29 (4) / (4) 44 (4) / (4) 2 9 (the numbers in parentheses are reduced Number of pitched electrode fingers) IDT wavelength in II: 2 · 〇6μηι, λ 12: 1.88μΐϋ Reflector wavelength AR: 2.07μτη 37 Ϊ Paper size applies Zhongguan specifications ⑽ public love) ~ '------ --------------- Order --------- line (please read the >!-Intentions on the back before filling in this page) 543288 A7 _B7___ V. Description of the invention l) Number of reflectors: 100 IDT-IDT interval: 0.50 and 12 The interval between the electrode fingers of the wavelength λ II and wavelength λ 12 (215, 216, 217, 218 in Figure 29): 0 · 25 λ 11 + 0.25 λ 12 IDT—reflector interval: 0.47AR duty cycle (duty): 0.60 (the same for IDT and reflector)

Electrode film thickness: 0.080 λ II The following shows the detailed design of the surface acoustic wave resonator 202: Cross width W: 40.6 into the number of IDT: 241 wavelengths λ (the same for IDT and reflectors): 1. 97 μm number of reflectors · _ 30 IDT-reflector intervals: 0.50λ Duty ratio (duty): 0.60 (Same for IDT and reflector) Electrode film thickness: 0.084 λ The detailed design of SAW resonator 203 is shown below: Cross width W: 49.1 λ Number of IDTs: 401 wavelengths λ (both IDT and reflectors): 2 · 04μηι Number of reflectors: 30 IDT—Reflector interval: 0.50λ Duty ratio: 0.60 (both IDT and reflectors) Same) Electrode film thickness: 0.080 λ The above "interval" represents the center of two adjacent electrode fingers (the paper size of the wide coat applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ----- --------------- Order --------- line (please read the notes on the back before filling out this page) 543288 A7 ______ B7 __ 5. Description of the invention (I 》 (Center of the direction). Next, each characteristic of the third embodiment is measured, and the results are shown in FIG. 30 and FIG. 31. FIG. 30 A graph showing the measurement results of the amplitude balance between the balanced signal terminals corresponding to the frequencies in the configuration of the third embodiment is shown in FIG. 31. As a comparison, FIG. 30 and FIG. Fig. 31-The same shows the amplitude balance and phase balance of the configuration of the second comparative example in which the IDT206C shown in Fig. 32 is not subjected to thinning weighting adjacent to the IDT206, instead of the IDT206C. The configuration of the comparative example is completely the same as the third example except that IDT206C is replaced with IDT206C without thinning. The frequency range of the passband in the PCS reception filter is 1930MHz ~ 1990MHz. In the second comparative example, the maximum amplitude balance is -1.6dB ~ + 0.7dB (deviation of 2.3dB). In contrast, in the third embodiment, it is -1.5dB ~ + 0.7dB (deviation of 2.2dB). ), The amplitude balance is improved O.ldB. Second, the phase balance is 162 degrees to 182 degrees (deviation of 20 degrees) in the second comparative example, and in contrast, it is 162 degrees to 181 degrees in the third embodiment. (Deviation of 19 degrees), the phase balance is improved By the implementation of thinning weighting, the polarity of the electrode fingers adjacent to IDT205 and IDT206 are in the second embodiment, and + and + are both signal electrode fingers. In the third embodiment, IDT204 and IDT204 and The polarities adjacent to IDT205 are the same as one and +, which has the effect of improving left-right asymmetry. As explained above, in the third embodiment, a surface acoustic wave filter having a balanced-unbalanced transform function is adapted to the Chinese National Standard (CNS) A4 specification for 39 wood paper sizes adjacent to two IDTs ( 210 X 297 mm) -------- ^ --------- Clear 2 Read the precautions on the back before filling this page) 543288 A7 _____B7_____ V. The electrode fingers of the invention description Compared with the conventional surface acoustic wave filter, the weighting can obtain a surface acoustic wave filter with improved balance between the balanced signal terminals. Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIGS. 33 to 41. In the fourth embodiment, the EGSM reception filter will be described as an example. The surface acoustic wave device of the fourth embodiment is a series of two longitudinally-coupled resonator-type surface acoustic wave filters 1918 and 1920 in which the phase of an input signal and an output signal shown in FIG. 18 differs by about 180 degrees. 1906, 1907 side, connected in parallel on the unbalanced signal terminal 1905 side, with balanced-unbalanced conversion function, and two longitudinally coupled resonator-type surface acoustic wave filters 1918, 1920 The longitudinally coupled resonator-type surface acoustic wave filters 1918, 1918 are thinned and weighted on the aforementioned longitudinally coupled resonator-type surface acoustic wave filter 1920, and have virtual electrodes 1901b. In the fourth embodiment, four longitudinally-coupled resonator-type surface acoustic wave filters 1918 and 1920 are formed on the piezoelectric substrate 8 through the A1 electrode. All of them have the same design except that the phase of the signal and the output signal differ by about 180 degrees and that they are weighted. In the fourth embodiment, similar to the third embodiment, a plurality of narrow-pitch electrode fingers are provided between two IDTs adjacent to each other. The structure of the fourth embodiment is basically the same as that of the second embodiment shown in Fig. 68 except for the point of weighting. Longitudinal Coupled Resonator Surface Acoustic Wave Filter 丨 Detailed Design of 918 40 Paper Size Applicable to Chinese National Standard (CNS) A4 (210 X 297 mm) --------------- ------ Order --------- Line C, please read the notes on the back before filling in this page) 543288 A7 ____________._ B7____ 5. Description of the invention When the determined wavelength is λ 12, and the wavelength determined by the pitch of other electrode fingers is λ, it is as follows:

Crossing width W: 25.2 several II IDT (in the order of 1902, 1901, 1903): 23 (4) / (4) 26 (4) / 23 (4) Number of IDT wavelengths λ II: 4 · 204μιη, and 12: 3 · 854μηι Reflector wavelengths λ R: 4.279μτη Number of reflectors: 90 IDT-IDT interval: by the wavelength λ II and the wavelength; 112 electrode fingers Between: 0.25 λ 11 + 0.25 λ 12

Interposed between electrode fingers of wavelength λ 12: 0.50 to Ι2 IDT-reflector interval: 0.470 AR IDT duty cycle (duty): 0.720 reflector duty cycle (duty): 0.55 electrode film thickness: 0.08 λ II fourth This embodiment is characterized in that, with respect to the longitudinally coupled resonator-type surface acoustic wave filter 1918, the phase of the input signal to the output signal of the longitudinally coupled resonator-type surface acoustic wave filter 1920 is reversed by about 180 degrees and is inverted On both ends of IDT1901a, one of the electrode fingers connected to the unbalanced signal terminal 1905 is provided, and the dummy electrode 1901b is grounded on this part. Next, operations and effects of the fourth embodiment will be described. Fig. 34 shows the 41 wood paper size between the balanced signal terminals with respect to frequency in the configuration of the fourth embodiment, which is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -------- Order --------- line (please read the notes on the back before filling this page) 543288 A7 ___B7____ 5. Description of the invention (% C) Amplitude balance. For comparison, in FIG. 34, the degree of amplitude balance between the balanced signal terminals with respect to the frequency in the second conventional example of FIG. 68 is shown. The configuration of the second conventional example shown in FIG. 68 has the same configuration as that of the fourth embodiment except that thinning weighting is not performed. The frequency range of the passband in the EGSM reception filter is 925MHz ~ 960MHz. The amplitude balance between the balanced signal terminals in this range is -0.2dB to + 1.3dB (deviation 1.5dB) in the second conventional example, and in contrast to this, it is -0.7dB in the fourth embodiment. ~ 0.2dB (deviation 0.9dB), the amplitude balance is improved by about 0.6dB. The reason why the effect of the fourth embodiment is obtained will be described below. In the case of surface acoustic wave excitation, when electrode fingers of different polarities are adjacent, the excitation is performed between the electrode fingers. Fig. 35 shows the state of excitation of the surface acoustic wave at the periphery (the part enclosed by ◦ in Fig. 68) adjacent to the IDT in each of the surface acoustic wave filters 118 and 127 shown in Fig. 68. In Fig. 35, only three electrode fingers from the end of the adjacent portion of the IDT are shown, and other portions are omitted. The longitudinally-coupled resonator-type surface acoustic wave filters 118 and 127 of FIG. 68 correspond to the longitudinally-coupled resonator-type surface acoustic wave filter 2007, 2008, and IDT 113, 114, and 115 of FIG. 68, respectively. It corresponds to IDT2001, 2002, 2003, and IDT133, 134, and 135 of Fig. 68 correspond to IDT2004, 2005, and 2006 of Fig. 35, respectively. The part with 0 in the figure indicates that the surface acoustic wave is excited, and the part with X 'indicates that the surface acoustic wave is not excited. In the case of the second conventional example, in the longitudinally coupled resonator-type surface acoustic wave filter 2007, since the outermost power of each of IDT 2001, 2002, 2003 is 42, the paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) --------------------- Order --------- line (Please read the precautions on the back before filling this page) 543288 A7 ______ Β7 ____ 5. Description of the Invention (φΙ) A pole refers to a ground electrode, and there is no surface acoustic wave excitation between adjacent electrode fingers. On the other hand, in the longitudinally-coupled resonator-type surface acoustic wave filter 2008, the IDT2001 of the longitudinally-coupled resonator-type surface acoustic wave filter 2007 and the IDT2004 whose direction is reversed are used to make the longitudinally-coupled resonator-type surface acoustic wave filter The phase difference between the input signal and the output signal of the filter 2007 is about 180 degrees. Therefore, the outermost electrode of IDT2004 is the signal electrode, and the outermost electrode of IDT2005 and IDT2006 is the ground electrode. Therefore, in the longitudinally coupled resonator-type surface acoustic wave filter 2008, unlike the case of the longitudinally coupled resonator-type surface acoustic wave filter 2007, the surface acoustic wave excitation is performed even between the adjacent electrode fingers. When compared as a whole, compared with the longitudinally coupled resonator-type surface acoustic wave filter 2007, in the longitudinally coupled resonator-type surface acoustic wave filter 2008, the number of positions where the surface acoustic wave is excited is increased, and there are two Office. Accordingly, in the second conventional example, in the longitudinally-coupled resonator-type surface acoustic wave filter 2007 and the longitudinally-coupled resonator-type surface acoustic wave filter 2008, the effective current of the surface acoustic wave in the space between adjacent electrode fingers As a result, the intensity distributions are different. As a result, among the three resonance modes shown in FIG. 72, the interval between the resonance mode located at the center and the resonance mode located at the highest band side is different. The balance between the balanced signal terminals deteriorates. Next, FIG. 36 shows the excitation of the surface acoustic wave of the IDT adjacent periphery (the part enclosed by 0 in the figure) of the longitudinally coupled resonator-type surface acoustic wave filters 1918 and 1920 shown in FIG. 33. Vibration status. In Fig. 36, the same as Fig. 35, showing only the 3 43 paper size from the end of the part adjacent to the IDT is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ------ -------------- Order --------- line (please read the notes on the back before filling this page) 543288 B7 V. Description of the invention Electrode finger, others It is omitted. The longitudinally-coupled resonator-type surface acoustic wave filters 191δ and 1920 in FIG. 33 correspond to the longitudinally-coupled resonator-type surface acoustic wave filters 2107 and 2108 in FIG. 36, and the longitudinally-coupled resonator-type surface acoustic wave filters in FIG. 33, respectively. The IDT1902, 1901, and 1903 of the wave filter 1918 correspond to IDT2102, 2101, 2103 of FIG. 36, and the IDT1901a, 1902, and 1903 of the longitudinally coupled resonator-type surface acoustic wave filter 1920 of FIG. 33 respectively correspond to FIG. 36. IDT 2104, 2105, 2106. In the case of the fourth embodiment, by inverting the direction of the IDT connected to the input side, the longitudinally coupled resonator-type surface acoustic wave filter 2107 and the ordinate that makes the phase of the input signal and the output signal differ by about 180 degrees In the resonator-type surface acoustic wave filter 2108, the outermost electrode fingers of the IDT 2104 are thinned and weighted, and a dummy electrode 2109 (the dummy electrode 1901b in FIG. 33) is provided and grounded. Therefore, in the longitudinally coupled resonator-type surface acoustic wave filter 2108, in the portion 2110 adjacent to two IDTs on one side, the signal electrode fingers and the ground electrode fingers are alternately arranged, and the surface acoustic wave is excited, and In contrast, in the two IDT adjacent parts 2111 on the other side, because the three ground electrode fingers are side by side, the part of the surface acoustic wave that is not excited generates two toe effects, and the longitudinal coupling g is vibrator-type elastic.袠 Surface wave filter 2107 and 纮: Coupling resonator type elastic table echo filter 2108, the total number of places where the surface acoustic wave is not excited between the electrode fingers, that is, The total number of excitations becomes equal, so compared with the ^ _ mesh, harmonious _ -------------------- order --------- IAW. (Please read the precautions on the back before filling out this page) 44 543288 A7 _____B7______ 5. The gap between the invention's explanatory formula becomes smaller, and the amplitude balance between the balanced signal terminals is improved. For example, by connecting two sections in series as shown in Figure 37 The first longitudinally coupled resonator-type surface acoustic wave filter 2201 of the longitudinally coupled resonator-type surface acoustic wave filter 2201 is shown, and For the first longitudinally coupled resonator-type surface acoustic wave filter 2202, the direction of the IDT 2203 of the longitudinally coupled resonator-type surface acoustic wave filter 2201a connected on the output side of the second segment is reversed, and has the first longitudinally coupled resonance The device-type surface acoustic wave filter 2202 and the second longitudinally-coupled resonator-type surface acoustic wave filter 2204 that make the input signal to the output signal phase approximately 180 degrees apart are connected in parallel to each longitudinally-coupled resonator-type elastic surface of the first stage. The center IDT of the wave filter 2201 constitutes an unbalanced signal terminal 2205, and the longitudinally coupled resonator-type surface acoustic wave filters 2201 and 2201a of the second stage are connected in series to form a balanced signal terminal 2206. In the above case, Next, the outermost electrode fingers of IDT 2203 are thinned and weighted. A dummy electrode 2207 is provided in this part and grounded. Based on this, two IDTs in the longitudinally coupled resonator-type surface acoustic wave filter on the output side are adjacent to each other. The excited state of the surface acoustic wave (the part enclosed by 0 in FIG. 37) is as shown in FIG. 38, and the first longitudinally coupled resonator-type surface acoustic wave filter 2202 and the second In the longitudinally coupled resonator-type surface acoustic wave filter 2204, the total number of places where the surface acoustic wave is not excited between the electrode fingers, that is, the total number of places where the surface acoustic wave is excited between the electrode fingers becomes equal, so the signal is balanced. The amplitude balance between the terminals is improved. Also, as shown in FIG. 39, the longitudinally coupled resonator-type elastic 45 wood paper not in the second stage applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ----------- --------- Order --------- ^ (Please read the precautions on the back before filling out this page) 543288 A7 _ B7___ V. Description of the invention The central IDT of the surface wave filter, and The direction of the outer IDT is reversed, so that the phase of the input signal to the output signal differs by about 180 degrees. Even in the foregoing case, the outermost electrode finger of the IDT2301 whose ID is reversed is implemented. The thinning weight is set, and a dummy electrode finger 2302 is set in this part and grounded. Accordingly, two IDTs in the longitudinally coupled resonator-type surface acoustic wave filter on the output side are adjacent to each other (surrounded by 0 in FIG. 39). Part) of the SAW excitation state, as shown in the figure, in the first longitudinally coupled resonator-type surface acoustic wave filter 2303 and the second longitudinally coupled resonator-type surface acoustic wave filter 2304, in the electrode finger The total number of places where surface acoustic waves are not excited, that is, the total number of places where surface acoustic waves between electrodes are excited It becomes equal, so the amplitude balance between the balanced signal terminals is improved. Also, as shown in FIG. 41, even if a 5IDT type longitudinally coupled resonator type surface acoustic wave filter is used instead of the 3IDT type in FIG. 33, In the case of a longitudinally coupled resonator-type surface acoustic wave filter, the outermost electrode finger on the IDT side of the IDT2401 whose direction is reversed is thinned and weighted. A dummy electrode finger 2402 is provided in this part and grounded. Therefore, in the first longitudinally coupled resonator-type surface acoustic wave filter 2403 and the second longitudinally coupled resonator-type surface acoustic wave filter 2404, the total number of places where the surface acoustic wave is not excited between the electrode fingers, that is, at the electrode The total number of places where the inter-finger surface acoustic waves are excited becomes equal, so the amplitude balance between the balanced signal terminals is improved. As in the fourth embodiment described above, two SAW filters in which the phase of the input signal and the output signal differ by about 180 degrees are connected in series at 46. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) '· -------------------- Order · ------- «(Please read the back of the page; I will fill in this page before filling in this page ) 543288 A7 ____B7__ 5. Description of the Invention (夂 f) The balanced signal terminal side is connected in parallel to the unbalanced signal terminal side, and has a balanced-unbalanced conversion function. It is then cascaded on two SAW filters one by one. The surface acoustic wave filter implements thinning weighting on the structure, and thus, a surface acoustic wave device having an improved balance between the balanced signal terminals can be obtained compared with a conventional surface acoustic wave device. Fifth Embodiment A fifth embodiment of the present invention will be described with reference to FIGS. 42 to 46. In the fifth embodiment, a description will be given by taking a DCS reception filter as an example. The fifth embodiment is that two longitudinally coupled resonator-type surface acoustic wave filters having an input signal and an output signal phase difference of about 180 degrees as shown in FIG. 16 are connected in series on a balanced signal terminal side and connected in parallel on an unbalanced side An example in which a signal terminal side has a balanced-unbalanced conversion function is weighted. In the fifth embodiment, a longitudinally coupled resonator type surface acoustic wave filter 2501 and a surface acoustic wave resonator 2502 connected in series with the longitudinally coupled resonator type surface acoustic wave filter 2501 are formed by the A1 electrode on the aforementioned piezoelectric substrate 8. And 2503. The two longitudinally coupled resonator-type surface acoustic wave filters are all of the same design except that the phase of the input signal to the output signal is about 180 degrees apart. In the fifth embodiment, similar to the third embodiment, a plurality of narrow-pitch electrode fingers are provided between two adjacent IDTs. The detailed purpose of the longitudinally coupled resonator-type surface acoustic wave filter is determined by setting the wavelength determined by the pitch of the narrow-pitch electrode fingers to be I 12. When the wavelength determined by the pitch of other electrode fingers is λ II, as follows··

Cross width: 37.12 λ II 47 Wood paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) ~--------------------- Order · -------- line (please read the notes on the back before filling this page) 543288 A7 _B7___ V. Description of invention (屮 L) Number of IDT (in the order of 2504, 2505, 2506): (4) 19 / (4) 3 1 (4) / 19 (4) (The number of electrode fingers with reduced spacing is shown in parentheses) IDT wavelength λ II ·· 2 · 156μηι, λ 12: 1 · 926μπι Reflector wavelength AR · \ 2.177μιη Number of reflectors: 150 IDT-IDT interval: sandwiched by each electrode finger of wavelength λΐΐ and wavelength λΙ2: 0.25 λ 11 + 0.25 λ 12, sandwiched by electrode fingers of wavelength λ 12: 0.50 λ 12 IDT-reflector interval: 0.50Α R IDT duty cycle (duty) · 0.63 reflector duty cycle (duty): 0.60 electrode film thickness: 0.09 to 11 The following shows the surface acoustic wave resonator 2502 Detailed design:

Crossing width: 14.3 λ I IDT number: 241 IDT wavelength and reflector wavelength: 2.102 μηι Reflector number: 30

IDT-reflector interval: 0.50AR The detailed design of the surface acoustic wave resonator 2503 is shown below:

Crossing width: 37.1 λ I IDT number: 241 IDT wavelength and reflector wavelength: 2.023μπι Reflector number: 30

IDT—Reflex Inch Spacer: 0.50AR Wood paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) --------------------- Order --------- Line (please read the notes on the back before filling this page) 543288 A7 _________B7 V. Description of the invention if) The fifth embodiment is characterized in that it is relative to the surface acoustic wave filter 2507, The phase difference between the input signal and the output signal of the surface acoustic wave filter 2508 is about 180 degrees, and one of the inverted signal electrode fingers at the end of the IDT 2509 is removed, and a grounded virtual electrode 2510 is provided in this part. The ground electrodes of the three IDTs are made common through the virtual electrode 2510 and the street view is described, and the function and effect of the fifth embodiment will be described. First, FIG. 43 shows the amplitude balance between the balanced signal terminals with respect to frequency in the configuration of the fifth embodiment. For comparison, FIG. 44 and FIG. 43 show the degree of amplitude balance between the balanced signal terminals with respect to frequency in the third comparative example. The configuration of the third comparative example of Fig. 44 has the same configuration as that of the fifth embodiment except that the thinning weight is not applied. The frequency range of the pass band in the DCS reception filter is 1805MHz ~ 1880MHz. The degree of amplitude balance between the balanced signal terminals in this range is -1.0 dB to + 3.2 dB (deviation of 4.2 dB) in the third comparative example, while in the fifth embodiment it is -0.5 dB to + 1.5dB (2.0dB deviation), the amplitude balance is improved by about 2.2dB. The reason why the effect of the fifth embodiment is obtained will be described below. In the third comparative example shown in FIG. 44, as shown in FIG. 45, the surface acoustic wave adjacent to the IDT (the portion enclosed by ◦ in FIG. 44) is a surface acoustic wave. The number of excited locations is different between the first surface acoustic wave filter 2601 and the second surface acoustic wave filter 2602. In contrast, in the case of the fifth embodiment, as shown in FIG. 46, the IDT phase The number of places where the surface acoustic wave adjacent to the neighboring area (surrounded by ◦ in Figure 42) is excited is at the first longitudinally-coupled resonator-type surface acoustic wave filter. 49 The paper size applies the Chinese National Standard (CNS) A4 specification. (210 X 297 mm) -------------------- Order --------- (Please read the notes on the back before filling this page) 543288 A7 ________B7_____ 5. Description of the invention (@) 2511 and the second longitudinally coupled resonator-type surface acoustic wave filter 2512 are the same. Therefore, the interval between the resonance mode seen at the center of the frequency band and the resonance mode seen at the high frequency side of the three resonance modes shown in FIG. 72 is between the signals output from the two balanced signal terminals. It is consistent with the third comparative example. As described above, in the fifth embodiment, two longitudinally coupled resonator-type surface acoustic wave filters in which the phase of the input signal and the output signal differ by about 180 degrees are connected in series on the balanced signal terminal side and in parallel on the unbalanced signal terminal. On the other hand, it has a balanced-unbalanced conversion function and weights the structure. As a result, compared with the conventional surface acoustic wave device, a surface acoustic wave device having improved balance between the balanced signal terminals is obtained. In addition, the grounding of the three IDTs is made common by including the dummy electrode 2510 provided at the removed position, so that the grounding of the surface acoustic wave device is strengthened, and the insertion loss in the pass band and the attenuation outside the pass band are obtained. improve. In addition, the ground terminal of the IDT in the center can also be omitted. Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIGS. 47 to 54. In the sixth embodiment, the description is made by taking a DCS reception filter as an example. The sixth embodiment is the same as the third embodiment, and balanced signal terminals 2711 and 2712 are connected to two comb-shaped electrodes of two IDT2704s in a longitudinally coupled resonator-type surface acoustic wave filter 2701, respectively. In the balanced signal terminals 2711 and 2712, weighting is applied to the configuration of the electrical neutral point that is not grounded. In the sixth embodiment, the longitudinal 50-coat paper size formed by the A1 electrode on the aforementioned piezoelectric substrate 8 is applicable to the Chinese National Standard (CNS) A4 specification (210 x 297 mm) ~ ---------- ---------- Order --------- ^ (Please read the notes on the back before filling out this page) A7 543288 ___B7___ 5. Description of the invention (¥ j) Coupling resonator type elasticity The surface wave filter 2701 'and the surface acoustic wave resonators 2702 and 2703 connected in series with the longitudinally coupled resonator type surface acoustic wave filter 2701. The structure of the longitudinally coupled resonator-type surface acoustic wave filter 2701 is that IDT 2705 and 2706 are arranged on the left and right sides of the IDT 2704, and reflectors 2707 and 2708 are formed so as to sandwich these IDTs. In the sixth embodiment, similar to the third embodiment, a plurality of narrow-pitch electrode fingers are provided between two IDTs adjacent to each other (at 2709 and 2710 in Fig. 47). Terminals 2711 and 2712 are balanced signal terminals, and 2713 are unbalanced signal terminals. In Fig. 48, an enlarged view between IDT 2704 and 2705 of Fig. 47 is shown. The outermost electrode finger 2704a of the IDT 2704 connected to the balanced signal terminal 2711 is weighted by the cross width, and a dummy electrode 2705a is provided at the position where the weighting and elimination are performed to ground. The detailed design of the longitudinally coupled resonator-type surface acoustic wave filter 2701. When the wavelength determined by the pitch of the narrow-pitch electrode fingers is λ 12 and the wavelength determined by the pitch of other electrode fingers is λ II, it is as follows:

Cross width: The portion where cross width weighting is not applied (2805 in Figure 48): 71.2 λ II

Cross-weighted part (2806 in Figure 48): 35 · 6 λ II 1DT (in the order of 2705, 2704, 2706): 21 (4) / (4) 35 (4) / (4) 21 (The number in the brackets indicates the number of electrode fingers with reduced spacing) IDT wavelength λ II: 2 · 18μιη, λ12: 1.96μηι 51 i Paper size applies Chinese National Standard (CNS) A4 (210 χ 297 mm) ^ I -------------------- Order · ------- I —Awi (Please read the notes on the back before filling in this page) 543288 A7 _B7___ V. Description of the invention (dagger) Reflector wavelength λ R: 2.18μηι Number of reflectors: 150 IDT-IDT interval: sandwiched by the electrode fingers of the wavelength λ II and the wavelength λ 12 (2714 in Figure 47): 0.25 λ 11 + 0.25 λ 12

Interposed between electrode fingers with a wavelength of λ 12 (2715 in Fig. 47): 0.50 λ 12 IDT-reflector interval: 0.460 λ R IDT duty cycle (duty): part without narrowing pitch: 0.63, narrowing pitch Part of: 0.60

Reflector duty (duty): 0.57 Electrode film thickness: 0.09 λ II The following shows the detailed design of the SAW resonator 2702:

Crossing width: 23.6λ I Number of IDT: 241 IDT wavelength and reflector wavelength: 2.12μιη Number of reflectors: 30

IDT-reflector spacing: 0.50AR The detailed design of the SAW resonator 2703 is shown below:

Crossing width: 58.5 λ I Number of IDTs: 241 IDT wavelength and reflector wavelength: 2.04μιη Number of reflectors: 30

IDT-reflector interval: 0.50AR The sixth embodiment is characterized in that it is adjacent to the ground electrode finger and forms a pair of electrical clothes on both ends of IDT2704 connected to the center of the balanced signal terminal. ) A4 size (210 X 297 mm) -------------------- Order · -------- * 5 ^ IAV. (Please read the back first (Please note this page before filling out this page) 543288 A7 _B7 _ V. Description of the invention)

1 I pole fingers are cross-weighted electrode fingers 2704a with cross-width weighting. Next, dummy electrodes 2705a and 2706a are provided at the positions where cross-width weighting is performed, and grounded. Next, operations and effects of the sixth embodiment will be described. In Fig. 49, the amplitude balance between the balanced signal terminals with respect to frequency in the configuration of the sixth embodiment is not shown. For comparison, FIG. 50 and FIG. 49 show the amplitude balance between the balanced signal terminals with respect to frequency in the fourth comparative example. The configuration of the fourth comparative example in FIG. 50 has the same configuration as that of the sixth embodiment, except that the longitudinally coupled resonator-type surface acoustic wave filter 2701a of which the electrode fingers of the rain end of the central IDT are not weighted crosswise is used. . The frequency range of the pass band in the DCS receiver furnace is from 1805MHz to 1880MHz. The amplitude balance between the balanced signal terminals in this range is -1.3dB to + 3.3dB (deviation 4.6dB) in the fourth comparative example. In contrast, in the sixth embodiment, it is -2.0 dB to + 1.9 dB (deviation 3.9 dB), and the amplitude balance is improved by about 0.7 dB. In the fourth embodiment, the amplitude balance between the balanced signal terminals is largely biased toward the + side. However, in the sixth embodiment, the deviation between the + direction and one direction is approximately equal. As in the sixth embodiment, the solution in which the deviation between the + direction and the one direction is substantially equal, compared with a large deviation to either the + side or one side, has the advantage that the noise level of the in-phase signal becomes smaller. The plan is superior in this regard. The reason for obtaining the effect of the sixth embodiment is that by applying cross-width weighting to the electrode fingers at the two ends of the central IDT2704 adjacent to the ground electrode fingers, the wood paper size is applicable to the Chinese National Standard (CNS) A4 specification (21 × 297 mm). %) -------------------- Order * ------- IIAWI (Please read the notes on the back before filling this page) 543288 A7 ___B7 —__ V. Description of the invention (then the dummy electrode is 'grounded' at the point where the cross-width weighting is performed. According to this, the electrode fingers at both ends of the IDT connected to the balanced signal terminal 2711 and the IDT connected to the balanced terminal 2712 are ground electrodes. "Adjacent" therefore has the same relationship with the polarity of the adjacent electrode fingers. The results of investigating the optimal cross-weighted optimal 値 are described below. The survey method is as follows: In the configuration of Figs. 47 and 48, The ratio of the cross width 2805 of the cross-weighted portion to the cross width 2806 of the weighted portion (hereinafter referred to as the cross-width weighted ratio) was changed, and the amplitudes of the signal terminals were balanced within the passing band. Changes in balance The cross-width weighting ratio is 1 in the case of FIG. 50 without weighting, and in the case of FIG. 47, it is 1/2, and for the cross-width weighting ratios of 1/4, 1/2, and 3/4. Analyze the amplitude balance between the balanced signal terminals. Figure 51 shows the result of the amplitude balance between the balanced signal terminals when the cross-width weighting ratio is changed. Figure 51 shows the amplitude between the balanced signal terminals. The degree of balance depicts the deviation on the + side. According to FIG. 51, when the weighting ratio of the cross width is about 0.5, that is, when weighting is performed at an approximately center position of the electrode finger, the balance in the frequency band is passed. The amplitude balance between the signal terminals is the smallest. This is to weight the electrode fingers at both ends of the central IDT at approximately the center position, ground the weighted electrode fingers, and accordingly, the IDT connected to the balanced signal terminal 2711 On the electrode fingers connected to both ends of the IDT connected to the balanced signal terminal 2712, since the ground electrode fingers are adjacent to each other at about a half of the overall cross width, the relationship with the polarity of the adjacent electrode fingers becomes 54 Applicable paper size for China National Standard (CNS) A4 (210 X 297 mm) -------------------- Order --------- ^ «AWI (please read the notes on the back before filling this page) 543288 B7 V. Description of the Invention (P) Same effect. As explained above, in the sixth embodiment, a longitudinally coupled resonator-type surface acoustic wave One IDT (preferably the central IDT) of the filter is connected with balanced signal terminals on the comb-shaped electrodes of the two poles, and the electric neutral point is not grounded. In this configuration, the central IDT is positioned at a substantially central position. The electrode fingers at both ends are weighted crosswise, and the virtual electrode provided at the position cut off by weighting is grounded. As a result, compared with the conventional surface acoustic wave device, the amplitude balance between the balanced signal terminals can be improved. Surface acoustic wave device. Although the sixth embodiment has been described with a configuration in which electrode fingers connected to both ends of an IDT connected to a balanced signal terminal are adjacent to ground electrode fingers on both sides, even a ground electrode such as that shown in FIG. 52 is described. In the configuration in which the finger and the signal electrode finger are adjacent on one side, only the signal electrode finger on the side adjacent to the ground electrode finger is cross-weighted, and the virtual electrode provided at the position removed by weighting is obtained through IDT. By grounding, a surface acoustic wave device with improved amplitude balance between the balanced signal terminals can be obtained. As shown in FIG. 53, even in a configuration in which balanced signals are taken out from the two poles of two or more IDTs, the outermost electrode fingers of the two IDTs are cross-weighted, and the weighted electrode fingers are passed through the IDT and The reflector is grounded, thereby improving the amplitude balance between the balanced signal terminals. Although the sixth embodiment has been described with a configuration in which the longitudinally coupled resonator-type surface acoustic wave filter is a 3IDT type, even for example, the In this case, as shown in Fig. 54, for the electrodes on both ends of the IDT where the balanced signal is taken out, the paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm) ---------- ---------- Order --------- line (please read the precautions on the back before filling this page) 543288 A7 ____B7 ____ 5. Description of the invention (⑼) Refers to the implementation of cross-width weighting The ID electrode is used to ground the dummy electrode provided at the position cut out by weighting, thereby improving the amplitude balance between the balanced signal terminals. Seventh Embodiment A seventh embodiment of the present invention will be described with reference to FIGS. 55 to 61. In the seventh embodiment, a PCS reception filter will be described as an example. The seventh embodiment is the same as the third embodiment, and balanced signal terminals are connected to comb-shaped electrodes of two IDTs of an IDT in a longitudinally coupled resonator-type surface acoustic wave furnace, respectively. An example of the weighting of the constitution of the sexual points. In the seventh embodiment, a longitudinally coupled resonator-type surface acoustic wave filter 2901 and each surface acoustic wave resonator connected in series with the longitudinally coupled resonator-type surface acoustic wave filter 2901 are formed by the A1 electrode on the aforementioned piezoelectric substrate 8. 2902 and 2903. The configuration of the seventh embodiment is basically the same as that of Fig. 29 of the third embodiment. The seventh embodiment is characterized in that the duty ratios of the electrode fingers 2919 and 2920 are 0.40. In the seventh embodiment, a grounded shielded wire 2921 is inserted between the signal wire 2912 and the balanced signal terminal 2910. In this way, a grounded shielded wire is inserted adjacent to the signal electrodes, whereby the bridge capacitance between the signal electrodes is reduced, and a surface acoustic wave device capable of further improving the balance between the signal terminals can be obtained. The operation and effect of the seventh embodiment will be described below. Fig. 56 shows the amplitude balance between the balanced signal terminals with respect to frequency in the configuration of the seventh embodiment. In Fig. 57, the degree of phase balance is shown. For comparison, the paper size of Fig. 56 applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) -------------------- Order ----- --- * line (please read the precautions on the back before filling this page) 543288 A7 __B7_______ 5. The description of the invention 56 and Figure 57 also show the amplitude balance between the balanced signal terminals in the second comparative example in Figure 32 Degree, phase balance. The configuration of the second comparative example in FIG. 32 is completely the same as that of the seventh embodiment except that the duty ratio of the electrode fingers adjacent to IDT 2904 and 2906 of IDT 2905 is not changed. The frequency range of the passband in the PCS reception filter is 1930MHz to 1990MHz. The deviation of the phase balance between the balanced signal terminals in this range is almost unchanged in the seventh embodiment and the second comparative example, but the amplitude balance between the balanced signal terminals is -0.5 dB in the second comparative example. ~ 2.3dB (deviation 2.8dB), in contrast, in the seventh embodiment, it is -0.6dB to + 2.0dB (deviation 2.6dB), and the amplitude balance is improved by about 0.2dB. Furthermore, in the second comparative example, the amplitude balance and phase balance between the balanced signal terminals are largely biased to either the + side or the-side. However, in the seventh embodiment, the difference between the deviation of the + direction and the-direction changes. small. As in the seventh embodiment, a solution in which the difference between the + direction and the-direction is small is smaller than that of the + side or the-side, and the noise level of the in-phase signal is smaller. The example scheme is superior in this regard. The reason for obtaining the effect of the seventh embodiment is that the duty ratio (duty) of the electrode fingers of IDT2905 adjacent to each IDT2904, 2906 is smaller than the duty ratio (duty) of other electrode fingers. Conversion efficiency between the total capacitance m31 electrical signal of the electrode fingers connected between the balanced signal terminals 2910 and 2911 and the surface acoustic wave. The total capacitance of the electrode fingers is different, especially in the vicinity of the two IDTs. Therefore, as in the seventh embodiment, by adjusting the electrode of this part, the paper size of the paper is applicable to the Chinese National Standard (CNS) A4. Specifications (210 X 297 mm) -------------------- Order --------- ^ (Please read the notes on the back before filling in this (Page) A7 543288 5. The duty ratio (duty) of the description of the invention can get the maximum effect. To further obtain the effect, as shown in Fig. 58, the duty ratios of several electrode fingers close to two IDTs adjacent to each other can be adjusted. Next, as another structure of the seventh embodiment, FIG. 60 shows that the duty ratios of the electrode fingers (3001 and 3002 in FIG. 59) adjacent to IDT2905b of IDT2904a and IDT2906a are smaller than those of other components as shown in FIG. 59. The phase balance is shown in Fig. 61 for the amplitude balance between the terminals of the balanced signal terminals with respect to the frequency of the duty cycle of the electrode fingers. At this time, the duty ratio of the electrode fingers 3001 and 3002 is 0.40. For comparison, FIG. 60 and FIG. 61 show the amplitude balance and phase balance between the balanced signal terminals in the configuration of the second comparative example of FIG. 32 at a glance. The deviation of the phase balance between the balanced signal terminals in this range is almost unchanged in the modification of the seventh embodiment and the second comparative example, but the amplitude balance degree between the balanced signal terminals is-in the second comparative example. 0.5dB to + 2.3dB (deviation 2-8dB). In contrast, in the modification of the seventh embodiment, it is -0.5dB to + 2.0dB (deviation 2.5dB). The amplitude balance is improved by about 0.3dB. As shown in FIG. 59, the effect of the present invention can be obtained by adjusting the duty of the electrode fingers of the IDT connected to the unbalanced signal terminal. Of course, in addition to this, adjusting the duty ratio (duty) of the IDT2905b can also obtain the effect of the present invention. As described above, in the seventh embodiment, balanced signal terminals are connected to comb-shaped electrodes of two IDTs of an IDT in a longitudinally coupled resonator-type surface acoustic wave filter without an electrically neutral point to ground. At this 58 wood paper scale, the Chinese National Standard (CNS) A4 specification (210 X 297 metric degrees) is used. &Quot; " " -------------------- ^ -------- 1 l ^ wl (please read the back of the page; I will fill in this page) 543288 A7 ____ B7_ V. Description of the Invention (Γ)) In the constitution, a part of the IDT, special It is a surface acoustic wave device that performs duty weighting on two adjacent IDTs, and can improve the amplitude balance between the balanced signal terminals compared with the conventional surface acoustic wave device. Example) An eighth embodiment of the present invention will be described with reference to Figs. 62 to 64. The eighth embodiment is different from the seventh embodiment in that only the duty ratio of the electrode fingers of IDT2905 adjacent to IDT2904 and IDT2906 ( duty) is 0.4. In the eighth embodiment, the duty ratio of the electrode fingers of the IDT 2905 connected to the balanced signal terminal 2910 (dut y) Together with other electrode fingers, it becomes smaller, for example, to 0.40. The other configurations are the same as those of the seventh embodiment. The operation and effect of the eighth embodiment will be described below. FIG. 63 shows In the configuration of the eighth embodiment, the degree of amplitude balance between the balanced signal terminals with respect to frequency is shown in FIG. 64. The degree of phase balance is shown in FIG. 64. For comparison, FIG. 63 and FIG. The amplitude balance and phase balance between the balanced signal terminals in the second comparative example. The phase balance between the balanced signal terminals is slightly worse than the second comparative example in the frequency range of the passband in the PCS reception filter, but The amplitude balance between the balanced signal terminals is improved by about 0.5 dB compared with the second comparative example. Furthermore, in the second comparative example, the amplitude balance and phase balance between the balanced signal terminals are greatly biased toward either the + side or one side. On the one hand, however, in the eighth embodiment, the difference between the + direction and the-direction becomes smaller. As in the eighth embodiment, a scheme in which the difference between the + direction and the-direction is small and greatly deviates from 59 ruler Applicable to China National Standard (CNS) A4 (210x 297 mm) '" -------------------- Order --------- ^ IAWI (Please read the precautions on the back before filling out this page) 543288 A7 I-------------_______ V. Description of Invention Compared with either + side or-side, there is noise level of in-phase signals The advantage of the smaller embodiment is that the solution of the eighth embodiment is superior in this point. As explained above, in the eighth embodiment, in the longitudinally coupled resonator-type surface acoustic wave filter, there are ~ 2 poles of IDT combs. Toothed electrodes are connected to balanced signal terminals, respectively, without an electrically neutral point to ground. In this configuration, all electrode fingers connected to one side of the balanced signal terminals are incorrectly weighted by duty, and Compared with the conventional surface acoustic wave device, a surface acoustic wave device with improved amplitude balance between the balanced signal terminals can be obtained. As shown in FIG. 62, when all the duty ratios of the electrode fingers of the IDT2905C connected to the balanced signal terminal 2910 are adjusted, the balance can be further improved. Instead, the phase balance deteriorates. However, as shown in FIG. 55 and FIG. 58, it is not necessary to adjust all the electrode fingers. It is only necessary to adjust the necessary number or make the adjustment amount of the duty ratio on each electrode finger different, that is, it can not balance. The phase balance between the signal terminals deteriorates, and the amplitude balance improves. (Ninth Embodiment) A ninth embodiment of the present invention will be described with reference to Fig. 65. The ninth embodiment basically has the same configuration as the seventh embodiment, but the duty ratio (duty) of the electrode fingers 3003 of IDT2905d is reduced in the vicinity of IDT2904 and IDT2905d, and in addition, IDT2905d is adjacent to lDT2906b. , The outermost signal electrode finger of IDT2906b is removed, and the thinning weighting of the virtual electrode 3004 provided with a ground at the removed position is performed. Next, operations and effects of the ninth embodiment will be described. By applying the Chinese National Standard (CNS) A4 specification (210 X 297 mm) on a vertical 60-wood paper scale (please read the precautions on the back before filling this page) f Order --------- Line-543288 A7 ______B7 V. Description of the invention) The coupling resonator type surface acoustic wave filter mixes two weighting methods, or multiple weighting methods, which improves the freedom of adjustment of the balance between the balanced signal terminals, and has the A surface acoustic wave device having a balanced signal terminal, which requires a degree of balance between the balanced signal terminals. In each of the above embodiments, as the piezoelectric substrate, a 40 ° 5 ° YcutX substrate is used to transmit the LiTa03 substrate. However, according to the principle that the effect can be obtained, the present invention is not limited to this substrate. 64 ~ 72 ° YcutX is used to transmit LiNb03, 41. . YcutX can also transfer LiNb03 and other substrates to achieve the same effect. Furthermore, in a surface acoustic wave device having a balanced-unbalanced conversion function using two surface acoustic wave filters including three or more IDTs, it is preferable that the electrode fingers of the surface acoustic wave filter are on the surface Weighting is performed in the direction in which the excitation of the wave becomes stronger. This makes it possible to suppress the narrowing of the passband width and improve the amplitude balance in the passband. As an example of weighting the direction in which the surface acoustic wave becomes stronger in this way, one surface acoustic wave device (first surface acoustic wave device) is not weighted. For the other surface acoustic wave device (second surface acoustic wave device), In the center of the IDT, the outermost electrode fingers (preferably signal electrode fingers) are both thinned, cross-weighted (including the formation of virtual electrodes), or tandem weighted (preferably). In addition, in each of the above embodiments, various weightings have been clarified, but they have mutually independent effects and effects. Even if two or more of them are arbitrarily combined to use them, the effects of the present invention can be obtained. For the present invention loaded with the elastic surface described in each of the above embodiments __ 61 wood paper rule 1 ^ National National Standard (CNS) A4 specification (2iq X 297) ~ --- ---------- ---------- Order ---------- line (please read the notes on the back before filling this page) 543288 A7 ------ —_Β7 _____ V. Description of the invention ( g6) The communication device of the wave device will be described below with reference to FIG. 66. As shown in FIG. 66, the communicator 3100 equipped with the surface acoustic wave device of the first to ninth embodiments is used as a receiver side (Rx side) for receiving, and includes: an antenna 3101, an antenna common unit / RFTop filter 3102, and the like. , Amplifier 3103, Rx interstage oscillator 3104, mixer 3105, IstIF filter 3106, mixer 3107, 2ndIF filter 3108, 1st + 2nd local synthesizer 3111, TCX〇 (Temperature Compensated Crystal Oscillator (temperature Compensation type quartz oscillator) 3112, frequency divider 3113, local filter 3114. From the Rx interstage filter 3104 to the mixer 3105, as shown by double lines in Fig. 66 ', in order to ensure the balance between the balanced signal terminals, it is best to send each balanced signal. In addition, the communication device 3100, as a radio transceiver side (Tx side) for transmission, shares the antenna 3101 and the antenna common unit / RFTop filter 3102, and further includes a TxIF filter 3121 and a mixer. 3122, Tx interstage filter 3123, amplifier 3124, coupler 3125, insulator 3126, APC (Automatic Power Control) 3127. Further, in the above-mentioned Rx inter-stage filter 3104, the surface acoustic wave devices of the first to ninth embodiments described above can be used. As mentioned above, the communication device 3100 improves the transmission characteristics while reducing the size of the surface acoustic wave device used. Therefore, it is possible to achieve miniaturization, especially miniaturization above the GHz band, and to achieve excellent transmission. Characteristics (communication characteristics). 62 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) -------------------- Order -------- -^ i ^ w— (Please read the precautions on the back before filling this page) 543288 A7 __B7__ V. Description of the invention (t /) [Effects of the invention] As described above, the surface acoustic wave device of the present invention uses at least A surface acoustic wave filter having at least two IDTs formed on a piezoelectric substrate along a surface acoustic wave transmission direction; at least one of input and output signal terminals of the aforementioned surface acoustic wave device is connected On the balanced signal terminal, electrode fingers of at least a part of the aforementioned surface acoustic wave filter are weighted. Therefore, in the above configuration, by implementing weighting, there is an effect that the degree of balance between the balanced signal terminals can be improved. As described above, the surface acoustic wave device of the present invention is formed on a piezoelectric substrate and forms an input IDT having a plurality of electrode fingers and an output idt having a plurality of electrode fingers along a surface acoustic wave transmission direction. At least one of the input IDT and the output IDT has different outermost electrode fingers, and each inner electrode finger has a weighted electrode finger structure. Therefore, in the above configuration, a weighted electrode finger is provided. For example, the effect of improving the balance (balance) between each balanced terminal can be exerted. As described above, the communication device of the present invention is characterized by using the above-mentioned surface acoustic wave device. Therefore, the above-mentioned structure can achieve miniaturization, especially miniaturization above the GHz frequency band, and achieves excellent transmission characteristics (communication characteristics). 63 This paper size applies the Chinese National Standard (CNS) A4 standard (210 X 297 mm). ) --------------------- Order --------- line (Please read the precautions on the back before filling this page)

Claims (1)

543288 C8 D8 6. Scope of patent application1. A surface acoustic wave device is provided with at least one surface acoustic wave filter, which has at least two comb electrodes formed on a piezoelectric substrate along the transmission direction of the surface acoustic wave. The input signal terminal and the output signal terminal for the surface acoustic wave filter are characterized in that at least one of the input signal terminal and the output signal terminal is connected to the balanced signal terminal, and at least a part of the surface acoustic wave filter is connected to the balanced signal terminal. The electrode fingers are weighted. 2. The surface acoustic wave device according to item 1 of the patent application range, wherein 'a part of the aforementioned electrode fingers is weighted to improve at least one of amplitude balance and phase balance between the pair of balanced signal terminals. 3. The surface acoustic wave device according to item 1 of the scope of patent application, wherein the weighting is based on at least one of the comb electrode portions adjacent to each other in the surface acoustic wave filter, and the comb electrode portions are adjacent to each other. Several electrode fingers from the outermost electrode finger are implemented. 4 · The surface acoustic wave device according to item 1 of the scope of the patent application, wherein the aforementioned weighting is based on at least one of the comb-shaped electrode portions adjacent to each other of the surface-acoustic wave filter, located adjacent to each other. Several electrode fingers near the outermost electrode finger are implemented. 5. The surface acoustic wave device according to item 1 of the patent application, wherein the aforementioned weighting is based on at least one of the comb electrode portions adjacent to each other of the surface acoustic wave filter, from the position where the comb electrode portions are adjacent to each other. The electrode fingers of the outermost electrode fingers are within a range of 1/2 of the surface acoustic wave transmission direction of the comb-shaped electrode portion. 6 · For the surface acoustic wave device in the scope of patent application No. 1, among which ('Please read the precautions on the back before writing this page), speech! This paper size applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) 543288 A8 B8 C8 _. The scope of the patent application is that the aforementioned weighting refers to at least one of the comb-shaped electrode portions of the aforementioned surface acoustic wave filters adjacent to each other. The outermost electrode finger adjacent to the aforementioned comb-shaped electrode portion is implemented. 7 · The surface acoustic wave device according to item 丨 of the patent application, wherein the electrode fingers of the aforementioned surface acoustic wave filters adjacent to each other in the comb-shaped electrode portion are a ground electrode finger and a signal electrode finger, respectively. At least one of the ground electrode finger and the signal electrode finger performs the weighting. 8 · The surface acoustic wave device according to item i of the patent application, wherein the weighted electrode fingers are the signal electrode fingers of the surface acoustic wave filter described above. 9 · The surface acoustic wave device according to item 丨 of the patent application, wherein The weighting is performed on the electrode fingers of the comb-shaped electrode portion connected to the balanced signal terminal of the surface acoustic wave filter. 10 · The surface acoustic wave device according to item 1 of the application, wherein the aforementioned surface acoustic wave filter has at least one comb-shaped electrode portion that is phase-inverted relative to other comb-shaped electrode portions, and the weighting system inverts the phase. The electrode fingers of the comb-shaped electrode section are implemented. 11 · The surface acoustic wave device according to claim 1, wherein the aforementioned weighting is a thinning weight. 12 · The surface acoustic wave device according to item 11 of the scope of patent application, wherein a dummy electrode is provided on the opposite bus bar opposite to the bus bar to which the aforementioned thinning-weighted electrode fingers are connected. 13 · If the surface acoustic wave device in the scope of patent application No.1, where ------ 2_________ This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm) (Please read the precautions on the back first (Fill in this page again), 1T: Line J 543288 A8 B8 C8 D8 6. The scope of patent application is for each of at least one of the comb electrode part connected to the aforementioned input signal terminal and the comb electrode part connected to the output signal terminal. On the electrode fingers, two or more continuous ground electrode fingers including the outermost electrode fingers positioned opposite to each other of the comb-shaped electrode portion are formed as weights. _ 14 · The surface acoustic wave device according to item 1 of the patent application, wherein a ground connection portion is provided to connect the electrode fingers connected to the ground ends of the comb-shaped electrode portions adjacent to each other through the aforementioned virtual electrode. 15 · The surface acoustic wave device according to item 1 of the patent application, wherein the aforementioned weighting is to make the cross width of the electrode fingers different from the other | g cross widths of the electrode fingers. 16 · For the surface acoustic wave device of the first scope of the patent application, the aforementioned weighting means that the electrode fingers are set shorter than other electrode fingers to make a solid package. -Π · The surface acoustic wave device according to item 15 of the scope of patent application, wherein the aforementioned cross-width weighting is performed substantially at the center of the cross direction; ^. 18 · The surface acoustic wave device according to item 15 of the scope of patent application, wherein the electrode fingers adjacent to the aforementioned cross-weighted electrode fingers are also cross-weighted, and a virtual electrode formed by bending is provided to facilitate the stomach. The two cross-width-weighted electrode fingers face each other. 19 · As for the surface acoustic wave device of the scope of application for patent No. 15, in #, the aforementioned cross-weighted electrode fingers are the outermost electrode fingers on one side of the adjacent comb type, and the comb type on the other side The electrode part is provided with a dummy electrode so that the electrode fingers with the cross-width weights face each other. 2〇 If the surface acoustic wave device of scope I9 of the patent application, in g, the aforementioned virtual electrode is grounded. ________ 1_______ This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) " ^ _ (Please read the precautions on the back before writing this page) 、 One M line 543288 Cut C8 D8 VI 、 Scope of patent application (please read the notes on the back before writing this page) 21 · For the surface acoustic wave device of the scope of patent application, the weighting is to make the duty cycle of the electrode fingers different from other electrode fingers. The duty cycle is weighted. 22 · The surface acoustic wave device according to item 1 of the patent application, wherein the aforementioned surface acoustic wave filter has at least three comb-shaped electrode portions, and at least one of the comb-shaped electrode portions adjacent to each other is thinned separately. , And the aforementioned weightings are different, respectively. 23 · The surface acoustic wave device according to item 1 of the patent application, wherein the two surface acoustic wave filters are provided, and each of the surface acoustic wave filters is thinned separately, and the foregoing weights are different from each other. 24. The surface acoustic wave device according to claim 1, wherein the surface acoustic wave filter has at least three comb-shaped electrode portions adjacent to each other, and at least one of the comb-shaped electrode portions adjacent to each other, Cross-width weighting is applied to a plurality of electrode fingers that are different from the outermost electrode fingers in the outermost region where the comb-shaped electrode portions are adjacent to each other, and in at least one of the different comb-shaped electrode portions adjacent to each other, the aforementioned The outermost electrode fingers adjacent to each other of the comb-shaped electrode portions are thinned and weighted. At the same time, the thinned weights are provided with a dummy electrode connected to an opposite bus bar. The thinned weighted electrode fingers are connected to each other. 25 · The surface acoustic wave device according to item 1 of the scope of patent application, wherein the aforementioned surface acoustic wave filter has at least 3 comb-type electric cells adjacent to each other _____4____ This paper standard is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) A8B8C8D8 543288 6. For the patent application pole, at least one of the comb electrode portions adjacent to each other is provided with the duty ratio of the outermost electrode fingers adjacent to each other of the comb electrode portions and The other electrode fingers are weighted with different duty ratios, and at least one of different comb electrode portions adjacent to each other is thinned out to the outermost electrode fingers of the comb electrode portions adjacent to each other. The above-mentioned thinning weighting unit is provided with a virtual electrode connected to the opposite bus bar, and the opposite bus bar is opposite to the bus bar connected to the thinning-weighted electrode finger. 26. The surface acoustic wave device according to item 1 of the patent application, wherein 'the two surface acoustic wave filters are provided, and in at least one of the comb-shaped electrode portions of one surface acoustic wave filter adjacent to each other, In the outermost region where the comb-shaped electrode portions are adjacent to each other, a plurality of electrode fingers that are different from the outermost electrode fingers are cross-weighted, and at least at least the comb-shaped electrode portions of the other surface acoustic wave filters are adjacent to each other. On one side, thinning weighting is applied to the outermost electrode fingers adjacent to each other of the comb-shaped electrode portions, and at the same time, the thinning weight is provided with a dummy electrode connected to an opposite bus bar. The bars are opposed to the bus bars to which the thinned weighted electrode fingers are connected. 27. The surface acoustic wave device according to item 1 of the application, wherein the aforementioned surface acoustic wave filter is provided with a balanced signal input-balanced signal output filter function. 28 · If the surface acoustic wave device of the first scope of the patent application, ____S___ This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) " — — (Please read the precautions on the back before塡 Write this page), 1T ·· line 543288 A8 B8 C8 D8 VI. Patent application scope 'The aforementioned surface acoustic wave filter is set to have a balanced signal input, an unbalanced IS output filter function, or an unbalanced signal input A balanced signal output filter function. 29. If the surface acoustic wave device according to item 27 of the patent application, wherein at least one of the comb-shaped electrode 邰 is described, it is divided in the direction of the cross width [| is two. 30. If the surface acoustic wave device according to item 27 of the patent application, wherein '' said the pair of balanced signal terminals are comb-shaped electrodes connected to the two poles of a comb-shaped electrode portion, respectively. 31. The surface acoustic wave device according to item 27 of the application, wherein at least one of the comb-shaped electrode portions is divided into two in the direction of surface acoustic wave transmission. 32. The surface acoustic wave device according to item 27 of the patent application, wherein there is an electrical neutral point for grounding between the paired balanced signal terminals described above. 3 · The surface acoustic wave device according to item 1 of the patent application, Among them, there are two aforementioned surface acoustic wave filters, and they are set to have a balanced signal input-balanced signal output chirp function. 34. The surface acoustic wave device according to item 1 of the application, wherein the two surface acoustic wave filters are two, and the phase difference between the output signal and the input signal is about 180 degrees. The device is sewn to have balanced signal input ~ unbalanced g # output furnace wave benefit work gb or unbalanced signal input_balanced signal output filter and waver function. This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) # · 线! ·, 543288 Store C8 D8 VI. Patent Application Scope (please first (Please read the notes on the reverse side and rewrite this page) 35. For example, the surface acoustic wave device in the scope of patent application No. 34, in which the surface acoustic wave filter is further cascaded on the unbalanced signal terminal side. 36. The surface acoustic wave device according to item 1 of the application, wherein the aforementioned surface acoustic wave filter is a longitudinally coupled resonator-type surface acoustic wave filter. 37. The surface acoustic wave device according to claim 36, wherein the longitudinally coupled resonator-type surface acoustic wave filter has an odd number of comb-shaped electrode portions. 38. The surface acoustic wave device according to item 37 of the application, wherein the longitudinally coupled resonator-type surface acoustic wave filter has three comb-shaped electrode portions. 39. The surface acoustic wave device according to claim 36, wherein the total number of electrode fingers of at least one comb-shaped electrode portion of the longitudinally coupled resonator-type surface acoustic wave filter is an even number. 40. The surface acoustic wave device according to item 39 of the application, wherein at least three comb-shaped electrode portions of the longitudinally coupled resonator-type surface acoustic wave filter are connected to a balanced signal terminal. The total number of electrode fingers of the type electrode portion is an even number. 41. The surface acoustic wave device according to item 39 of the application, wherein the comb-type electrode portion of the longitudinally coupled resonator-type surface acoustic wave filter of three or more comb-type electrode portions is located at least in the central portion. The total number of electrode fingers is even. 42 · The surface acoustic wave device according to item 1 of the scope of patent application, wherein, in the aforementioned surface acoustic wave filter, at least one of series or parallel _2____ This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) _______ 08 543288 § 6. The scope of patent application is to connect at least one surface acoustic wave resonator. 43 · If the surface acoustic wave device according to item 丨 of the patent application range, wherein, the surface acoustic wave filter is formed by cascading two or more surface acoustic wave filter sections. 44 · A surface acoustic wave device, characterized in that an input comb-type electrode portion having a plurality of electrode fingers and an output comb-type having a plurality of electrode fingers are provided on a piezoelectric substrate along a surface acoustic wave transmission direction. The electrode portion has a longitudinally coupled resonator type. The inner electrode finger has a weighted inner electrode finger that is different from the outermost electrode finger of at least one of the input comb electrode portion and the output comb electrode portion. Weighted electrode fingers. 45 · The surface acoustic wave device according to item 44 of the application, wherein one of the input comb electrode portion and the output comb electrode portion is for balance, and at least one of the comb electrode portions on the balance side is · Square has weighted electrode fingers. 46. The surface acoustic wave device according to item 44 of the patent application, wherein the aforementioned weighted electrode fingers are provided in a comb electrode section within a range from the next of the outermost electrode fingers to within 1/2 of all the electrode fingers. . 47. The surface acoustic wave device according to item 44 of the application, wherein at least one of the electrode fingers of the input comb-type electrode portion and the output comb-type electrode portion has two or more continuous ground electrodes formed thereon. This ground electrode finger includes the outermost electrode finger located opposite to other comb-shaped electrode portions. 48 · If the surface acoustic wave device in the scope of application for the patent No. 44, the paper size of this paper applies the Chinese National Standard (CNS) A4 specification (210 X 297 cm) (Please read the precautions on the back before filling this page), \ Second line 543288 Jaw C8 D8 6. In the scope of patent application (please read the precautions on the back before filling this page), the aforementioned weighted electrode fingers are set to control the electric field-free portion formed between the adjacent ground electrode fingers. The ground electrode refers to the grounded electrode 49 of at least one of the input comb-type electrode portion and the output comb-type electrode portion. For example, the surface acoustic wave device according to item 48 of the patent application scope, wherein the aforementioned input comb Of the two comb-shaped electrode portions for balancing and the “comb-balanced electrode portions for balancing”, the size of the non-electric field portion is set to be substantially the same. 50. The surface acoustic wave device according to item 44 of the patent application, wherein the aforementioned weighted electrode finger is set shorter than other electrode fingers. 51. The surface acoustic wave device according to item 44 of the patent application, wherein the first balancing electrode finger that faces the weighted electrode finger and is grounded extends in accordance with the length of the weighted electrode finger. Line 52 · The surface acoustic wave device according to item 44 of the scope of patent application, wherein the first balanced electrode finger facing to a position different from the aforementioned weighted electrode finger and grounded is extended to match the length of the weighted electrode finger, and is provided with The second electrode for balance and the virtual electrode formed by being bent to face the weighted electrode. 53. The surface acoustic wave device according to item 44 of the patent application, wherein it has an unbalanced-balanced conversion function. 54 · A communication device, characterized in that it uses a surface acoustic wave device according to item 1 of the scope of patent application. This paper size applies to China National Standard (CNS) A4 specification (21 ^ 979 ^)