JP4601411B2 - Surface acoustic wave device and communication device - Google Patents

Description

  The present invention relates to a surface acoustic wave device such as a surface acoustic wave filter or a surface acoustic wave resonator used in a mobile communication device such as a mobile phone, and a communication device including the same.

  Conventionally, surface acoustic wave devices have been widely used as frequency selective filters used in the RF stage of mobile communication devices such as mobile phones and automobile phones. In general, characteristics required for a frequency selective filter include a wide passband, a low loss, a high attenuation characteristic, and the like. Furthermore, in recent years, in order to reduce the size, weight, and cost of mobile communication devices, the number of components used has been reduced, and it has been required to add new functions to the surface acoustic wave device.

  One such function is a balanced-unbalanced conversion function such that the surface acoustic wave device can be configured as an unbalanced input-balanced output type or a balanced input-unbalanced output type. Here, the balanced input or balanced output means that a signal is input or output with a potential difference between two signal lines, while the unbalanced input or unbalanced output means that the signal is ground potential. An input or output having the potential of one line with respect to. In order to provide the surface acoustic wave device with a balanced-unbalanced conversion function, the signals of the signal lines have the same amplitude in the transmission characteristics within the passband between the balanced signal terminal and the unbalanced signal terminal. It is necessary that the phase is inverted 180 degrees, which are called amplitude balance and phase balance (hereinafter, these are collectively referred to as balance).

  Since conventional surface acoustic wave devices are generally unbalanced input-unbalanced output type surface acoustic wave devices, circuits and electronic components connected to the subsequent stage of the surface acoustic wave device are of a balanced input type. Has a circuit configuration in which a balanced-unbalanced converter (hereinafter also referred to as a balun) is inserted between the surface acoustic wave device and the subsequent stage. Similarly, in the case where the circuit or electronic component in the previous stage of the surface acoustic wave device is a balanced output type, the circuit configuration has a balun inserted between the previous stage and the surface acoustic wave device.

  Therefore, in order to reduce the number of parts used by eliminating such a balun, an unbalanced input-balanced output type surface acoustic wave device or a balanced input-unbalanced surface acoustic wave device having a balanced-unbalance conversion function is provided. The balanced output type surface acoustic wave device is being put to practical use.

  FIG. 16 shows a plan view of a conventional surface acoustic wave filter 1401 having such a balance-unbalance conversion function (see Patent Document 1). As shown in FIG. 16, in the surface acoustic wave filter 1401, three IDT (Inter-Digital Transducer) electrodes 1501 to 1503 are arranged close to each other along the surface acoustic wave propagation direction on the piezoelectric substrate, and a central IDT electrode 1501 is arranged. The IDT electrodes are connected to balanced signal terminals 1510 and 1511 so that they are connected in a cascade and electrically connected in series, and the polarities of the IDT electrodes 1501 are reversed on both sides of the central IDT electrode 1501. 1502 and 1503 are arranged, and each is connected to an unbalanced signal terminal 1520. With such a configuration, a balanced-unbalanced conversion function can be provided, and the impedance on the balanced signal terminals 1510 and 1511 is about four times (200Ω) that of the unbalanced signal terminal 1520 (50Ω). can do. In addition, reflectors 1601 and 1602 are arranged so as to sandwich IDT electrodes 1501 to 1503 arranged in proximity.

Patent Document 2 proposes a surface acoustic wave element 1701 having a balanced-unbalanced conversion function as shown in FIG. As shown in FIG. 17, in the surface acoustic wave element 1701, three IDT electrodes 1801 to 1803 are arranged close to each other along the propagation direction of the surface acoustic wave on the piezoelectric substrate, and the central IDT electrode 1801 is divided into two. Respectively connected to balanced signal terminals 1910 and 1911, IDT electrodes 1802 and 1803 having opposite polarities are arranged on both sides of the central IDT electrode 1801, and connected to the unbalanced signal terminal 1920. Here, of the IDT electrodes 1802 and 1803, the electrode not connected to the unbalanced signal terminal 1920 is grounded, and reflectors 1901 and 1902 are arranged so as to sandwich the IDT electrodes 1801 to 1803 arranged in proximity. ing. Further, of the two IDT electrodes 1802 and 1803 adjacent to the IDT electrode 1801, the outermost electrode finger adjacent to the IDT electrode 1801 located at the center is closer to the grounded IDT electrode (in this example, the IDT electrode 1802). A reactance component (capacitance 2001 in this example) is formed on the piezoelectric signal board (in this example, the balanced signal terminal 1910) or inside or outside the package on which the surface acoustic wave element 1701 is mounted. By adopting such a configuration, an attempt is made to improve the balance (particularly the phase balance).
Japanese Patent Laid-Open No. 11-097966 Japanese Patent Laid-Open No. 2004-096244

  18 to 20 show results of verifying the filter characteristics of the surface acoustic wave filter 1401 shown in FIG. 16 and the surface acoustic wave element 1701 having the configuration shown in FIG.

  18 is a diagram showing the frequency dependence of insertion loss, FIG. 19 is a diagram showing the frequency dependence of VSWR, FIG. 20 (a) is the amplitude balance, and FIG. 20 (b) is the frequency of the phase balance. It is the diagram which showed the dependence. 18 to 20, the solid line represents the characteristics of the surface acoustic wave element 1701 shown in FIG. 17 in which no reactance component is added to the balanced signal terminals 1910 and 1911 (that is, the structure of the surface acoustic wave filter 1401 shown in FIG. 16). The broken lines indicate the characteristics of the configuration in which the capacitor 2001 is connected in parallel as a reactance component to one of the balanced signal terminals 1910 and 1911, respectively. Here, among the broken lines, the long broken line shows the characteristic of the configuration in which the balanced signal terminal 1910 is connected, and the short broken line shows the characteristic of the configuration in which the capacitor 2001 is connected to the balanced signal terminal 1911 in parallel. From these figures, it is found that both the surface acoustic wave filter 1401 shown in FIG. 16 and the surface acoustic wave element 1701 having the configuration shown in FIG. 17 have large undulations (ripples) in the passband and a large VSWR. This is presumably because the impedance matching between the two balanced signal terminals 1510, 1511 and 1910, 1911 is not achieved. Further, it was confirmed that the balance of the surface acoustic wave element 1701 configured as shown in FIG. 17 is not improved as compared with the surface acoustic wave filter 1401 shown in FIG.

  As described above, the surface acoustic wave filter 1401 disclosed in Patent Document 1 and the surface acoustic wave element 1701 disclosed in Patent Document 2 have problems that the insertion loss and VSWR characteristics required as a frequency selection filter are not sufficient. There was a point.

  The present invention has been made in view of the above-described problems of the prior art, and has an object of having an excellent filter pass characteristic of low insertion loss and low VSWR, and a balance-unbalance conversion function. A surface acoustic wave device is provided.

  The surface acoustic wave device according to the present invention includes 1) a plurality of electrode fingers that are long on the lower surface of the piezoelectric substrate along the direction of propagation of the surface acoustic wave propagating on the piezoelectric substrate. Three or more odd-numbered IDT electrodes, reflector electrodes each provided on both sides of the odd-numbered IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction, and the IDT electrodes A surface acoustic wave element comprising a connection pad electrode connected to the surface and an annular ground electrode surrounding the IDT electrode, the reflector electrode, and the connection pad electrode is opposed to the annular ground electrode on the upper surface. A mounting substrate on which a ring-shaped ground conductor, a connection pad conductor facing the connection pad electrode, and a through-ground conductor connected to the ring-shaped ground conductor are formed; The annular ground electrode and the connection pad electrode are bonded to the annular ground conductor and the connection pad conductor, respectively, so as to face the upper surface of the mounting substrate, and the center of the odd number of IDT electrodes is mounted. Each of the IDT electrodes disposed on the substrate is divided into two of the opposing comb-like electrodes each having the electrode finger, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the IDT electrode disposed on the first electrode are connected to one of the comb-shaped electrodes as an unbalanced signal terminal and the other comb-shaped electrode is connected to the first electrode. The through-grounding conductor is connected to an annular grounding electrode, and the through-grounding conductor is connected to a virtual axis provided in a direction perpendicular to the propagation direction at the center of the IDT electrode disposed at the center. That it is formed asymmetrically is characterized in.

  The surface acoustic wave device according to the present invention is characterized in that 2) in the configuration of 1), the through-grounding conductor is disposed asymmetrically with respect to the virtual axis.

  The surface acoustic wave device according to the present invention is characterized in that, in 3) the configuration of 1), the through-grounding conductor has at least one diameter different from that of the other.

  The surface acoustic wave device according to the present invention is characterized in that 4) In the configuration of 1), the number of the through-grounding conductors is different on both sides of the virtual axis.

  Further, the surface acoustic wave device of the present invention is 5) In the configurations of 1) to 4) above, in addition to the group in which the through-grounding conductor is formed asymmetrically with respect to the virtual axis, And having a group formed symmetrically.

  In another surface acoustic wave device of the present invention, 6) an electrode that is long on a lower surface of the piezoelectric substrate in a direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. Three or more odd-numbered IDT electrodes having a plurality of fingers, and reflector electrodes each having a plurality of electrode fingers that are arranged on both sides of the odd-numbered IDT electrodes and that are long in a direction perpendicular to the propagation direction; A surface acoustic wave element including a connection pad electrode connected to the IDT electrode and an annular ground electrode surrounding the IDT electrode, the reflector electrode, and the connection pad electrode. A mounting substrate on which an annular ground conductor facing the ground electrode and a connection pad conductor facing the connection pad electrode are formed, with the lower surface of the piezoelectric substrate and the upper surface of the mounting substrate facing each other. An annular ground electrode and the connection pad electrode are mounted to be joined to the annular ground conductor and the connection pad conductor, respectively, and the IDT electrode disposed in the center of the odd number of IDT electrodes includes the electrode One of the opposing comb-like electrodes each having a finger is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal, and is positioned on both sides of the IDT electrode disposed in the center. The IDT electrode is configured such that the connection pad electrode is connected to one of the comb-shaped electrodes as an unbalanced signal terminal, and the other comb-shaped electrode is connected to the annular ground electrode. At least one of the electrode and the annular grounding conductor is in relation to a virtual axis provided in a direction orthogonal to the propagation direction at the center of the IDT electrode disposed at the center. That it is formed asymmetrically is characterized in.

  In the surface acoustic wave device according to the present invention, in 7) the configuration of 6) above, at least one of the annular ground electrode and the annular ground conductor has portions having different widths so as to be asymmetric with respect to the virtual axis. It is characterized by having.

  In the surface acoustic wave device according to the present invention, in the configuration of 8) or 6) or 7), at least one of the annular ground electrode and the annular ground conductor is formed asymmetrically with respect to the virtual axis. And a portion formed symmetrically with respect to the virtual axis.

  In addition, another surface acoustic wave device of the present invention includes: 9) an electrode that is long on the lower surface of the piezoelectric substrate in a direction perpendicular to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate. Three or more odd-numbered IDT electrodes having a plurality of fingers, and reflector electrodes each having a plurality of electrode fingers that are arranged on both sides of the odd-numbered IDT electrodes and that are long in a direction perpendicular to the propagation direction; A surface acoustic wave element including a connection pad electrode connected to the IDT electrode and an annular ground electrode surrounding the IDT electrode, the reflector electrode, and the connection pad electrode. A mounting substrate on which an annular ground conductor facing the ground electrode, a connection pad conductor facing the connection pad electrode, and a through ground conductor connected to the annular ground conductor is formed in front of the piezoelectric substrate. The annular ground electrode and the connection pad electrode are mounted to be joined to the annular ground conductor and the connection pad conductor, respectively, with the lower surface facing the upper surface of the mounting substrate, and the odd number of IDTs The IDT electrode disposed in the center of the electrode has the electrode fingers and one of the opposing comb-like electrodes divided into two, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the IDT electrode disposed in the center are connected to one of the comb-like electrodes with the connection pad electrode as an unbalanced signal terminal and the other of the comb-teeth-like shape. An electrode is connected to the annular ground electrode, and the through-ground conductor is provided in the center of the IDT electrode disposed in the center in a direction orthogonal to the propagation direction. It is formed asymmetrically with respect to the axis, and at least one of the annular ground electrode and the annular grounding conductor is characterized in that it is formed asymmetrically with respect to the virtual axis.

  The surface acoustic wave device according to the present invention is characterized in that, 10) in the configuration of 9), the through grounding conductor is disposed asymmetrically with respect to the virtual axis.

  The surface acoustic wave device according to the present invention is characterized in that, in 11) the configuration of 9), the through grounding conductor has at least one diameter different from the diameter of the other.

  The surface acoustic wave device according to the present invention is characterized in that in 12) the configuration of 9), the number of the through grounding conductors is different on both sides of the virtual axis.

  In the surface acoustic wave device according to the present invention, in 13) the configuration of 9) described above, at least one of the annular ground electrode and the annular ground conductor has portions with different widths so as to be asymmetric with respect to the virtual axis. It is characterized by having.

  In addition, in the surface acoustic wave device according to the present invention, 14) in any one of 9) to 13), in addition to the group in which the through grounding conductor is formed asymmetrically with respect to the virtual axis, It has a group formed symmetrically with respect to the axis.

  In the surface acoustic wave device according to the present invention, in any one of 15) to 9) to 13), at least one of the annular ground electrode and the annular ground conductor is formed asymmetrically with respect to the virtual axis. And a portion formed symmetrically with respect to the virtual axis.

  Further, the surface acoustic wave device of the present invention is 16) In any one of the constitutions 1) to 15) described above, the unbalanced signal terminal is arranged along the propagation direction in a direction perpendicular to the propagation direction. Surface acoustic wave having one IDT electrode having a plurality of long electrode fingers, and a reflector electrode having a plurality of long electrode fingers arranged on both sides of the IDT electrode and orthogonal to the propagation direction A resonator is connected.

  Further, the surface acoustic wave device of the present invention is 17) In any one of the above 1) to 15), the balanced signal terminal is long in the direction perpendicular to the propagation direction along the propagation direction. Surface acoustic wave resonance having one IDT electrode having a plurality of electrode fingers and a reflector electrode having a plurality of electrode fingers arranged on both sides of the IDT electrode and extending in a direction perpendicular to the propagation direction The child is connected.

  In the surface acoustic wave device according to the present invention, 18) In any one of 1) to 17) above, an electrode finger long in the direction orthogonal to the propagation direction is provided between the odd number of IDT electrodes. A plurality of inserted reflector electrodes are provided, and the distance between the centers of adjacent electrode fingers of the inserted reflector electrode is from the electrode fingers located at both ends to the electrode fingers located at the center. It is characterized by gradually becoming shorter.

  The communication device of the present invention is characterized in that it comprises 19) at least one of a reception circuit and a transmission circuit using the surface acoustic wave device according to any one of 1) to 18) as a filter means. It is characterized by being.

  According to the surface acoustic wave device of the present invention, 1) An electrode finger that is long in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate is provided on the lower surface of the piezoelectric substrate. A plurality of odd-numbered IDT electrodes of three or more, reflector electrodes each provided on both sides of the odd-numbered IDT electrodes, and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction; and IDT electrodes A surface acoustic wave element comprising a connection pad electrode connected to the electrode and an annular ground electrode surrounding the IDT electrode, reflector electrode, and connection pad electrode is provided on an upper surface of the annular ground conductor facing the annular ground electrode. In addition, the mounting substrate on which the connecting pad conductor facing the connecting pad electrode and the through grounding conductor connected to the annular grounding conductor are formed is annularly contacted with the lower surface of the piezoelectric substrate facing the upper surface of the mounting substrate. The electrode and the connection pad electrode are respectively bonded and mounted on the annular ground conductor and the connection pad conductor, and the IDT electrode disposed in the center of the odd number of IDT electrodes has an electrode finger and faces each other. One of the comb-like electrodes is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal, and the IDT electrodes located on both sides of the IDT electrode arranged in the center are one comb-like electrode. The connection pad electrode is connected to the electrode as an unbalanced signal terminal, and the other comb-like electrode is connected to the annular ground electrode. The through-ground conductor is propagated in the center of the IDT electrode disposed in the center. Since it is formed asymmetrically with respect to the virtual axis provided in the direction orthogonal to the ring, the path to ground the IDT electrode is asymmetric with respect to the annular ground electrode, the annular ground conductor, and the virtual axis. Since the inductance components are connected through the formed through-ground conductor, these inductance components function as a matching circuit, and as a result, low insertion loss and low VSWR filter pass characteristics. It will be excellent. Further, since the magnitude of such an inductance component can be easily adjusted by the design of the through-grounding conductor, it can have a function as a desired matching circuit, resulting in a low insertion loss and a low VSWR, and a filter passing characteristic. Can be obtained with good productivity. Further, the through-grounding conductor forming the inductance component is formed asymmetrically with respect to the virtual axis provided in the direction orthogonal to the propagation direction at the center of the IDT electrode disposed in the center. Since the parasitic capacitance formed by the electrode, the IDT electrode and the through grounding conductor can be made different on both sides of the virtual axis, fine adjustment is made so that the impedance between the two connection pad electrodes as balanced signal terminals is matched. Can be more balanced.

  According to the surface acoustic wave device of the present invention, 2) in the configuration of 1) above, when the through grounding conductor is disposed asymmetrically with respect to the virtual axis, the arrangement of the through grounding conductor is appropriately set. Since the size of the inductance component can be controlled by this, it is possible to easily obtain a function as a desired matching circuit, and to obtain a low insertion loss and a low VSWR with excellent filter passing characteristics with good productivity. It will be possible.

  According to the surface acoustic wave device of the present invention, 3) In the configuration of 1) above, when the through-ground conductor has at least one diameter different from the diameter of the other, the diameter of the through-ground conductor is set appropriately. Since the size of the inductance component can be controlled by this, it is possible to easily obtain a function as a desired matching circuit, and to obtain a low insertion loss and a low VSWR with excellent filter passing characteristics with good productivity. It will be possible.

  According to the surface acoustic wave device of the present invention, 4) in the configuration of 1) above, when the number of through-ground conductors is different on both sides of the virtual axis, the number of through-ground conductors is set appropriately so that the inductance component Therefore, it is possible to easily obtain a function as a desired matching circuit, and to obtain a low insertion loss and a low VSWR with excellent filter passing characteristics with high productivity. Become.

  According to the surface acoustic wave device of the present invention, 5) In the configuration of 1) described above, the through-grounding conductor is symmetrical with respect to the virtual axis in addition to the group formed asymmetrically with respect to the virtual axis. When a group is formed, the group formed symmetrically with respect to the virtual axis causes the capacitance formed by the two connection pad electrodes as the balanced signal terminal and the through grounding conductor to be on both sides of the virtual axis. Since it can be made equal and it is possible to suppress the occurrence of different parasitic capacitances in the two connection pad electrodes as balanced signal terminals, the balance is excellent.

  According to the surface acoustic wave device of the present invention, 6) An electrode finger that is long in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate is provided on the lower surface of the piezoelectric substrate. A plurality of odd-numbered IDT electrodes of three or more, reflector electrodes each provided on both sides of the odd-numbered IDT electrodes, and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction; and IDT electrodes A surface acoustic wave element comprising a connection pad electrode connected to the electrode and an annular ground electrode surrounding the IDT electrode, reflector electrode, and connection pad electrode is provided on an upper surface of the annular ground conductor facing the annular ground electrode. In addition, the annular ground electrode and the connection pad electrode are respectively in annular contact with the mounting substrate on which the connection pad conductor facing the connection pad electrode is formed, with the lower surface of the piezoelectric substrate facing the upper surface of the mounting substrate. The IDT electrode, which is bonded to the conductor and the connecting pad conductor and is disposed at the center of the odd number of IDT electrodes, has one electrode finger and each of the opposing comb-like electrodes is 2 Each of the IDT electrodes located on both sides of the IDT electrode disposed in the center is divided into one comb-like electrode and the connection pad electrode is connected to the unbalanced signal. The other comb-shaped electrode is connected to the annular ground electrode and at least one of the annular ground electrode and the annular ground conductor is connected to the center of the IDT electrode disposed in the center with respect to the propagation direction. Since it is formed asymmetrically with respect to the virtual axis provided in the orthogonal direction, an annular contact in which at least one is formed asymmetrically with respect to the virtual axis in the path until the IDT electrode is grounded. Since the inductance component is connected through the electrode and the annular ground conductor, these inductance components function as a matching circuit, resulting in a low insertion loss and a low VSWR, and excellent filter pass characteristics. It will be. In addition, since the magnitude of such an inductance component can be easily adjusted by designing at least one of the annular ground electrode and the annular ground conductor, it can have a function as a desired matching circuit, and can have a low insertion loss. In addition, a low VSWR can be obtained with good productivity with excellent filter passing characteristics. Further, at least one of the annular ground electrode and the annular ground conductor forming the inductance component is formed asymmetrically with respect to a virtual axis provided in the direction orthogonal to the propagation direction at the center of the IDT electrode disposed in the center. Therefore, since the parasitic capacitance formed by the reflector electrode, the IDT electrode, the annular ground electrode and the annular ground conductor can be made different on both sides of the virtual axis, two connection pad electrodes as balanced signal terminals can be obtained. Fine adjustment can be made so that the impedance between the two matches, and the degree of balance becomes higher.

  According to the surface acoustic wave device of the present invention, 7) In the configuration of 6) above, at least one of the annular ground electrode and the annular ground conductor has a portion having a different width so as to be asymmetric with respect to the virtual axis. In some cases, the size of the inductance component can be controlled by appropriately setting the width of at least one of the annular ground electrode and the annular ground conductor, so that a desired function as a matching circuit can be easily obtained and low insertion can be achieved. Loss and low VSWR are achieved, and a filter having excellent filter passing characteristics can be obtained with high productivity.

  According to the surface acoustic wave device of the invention, 8) in the configuration of 6) or 7), at least one of the annular ground electrode and the annular ground conductor is formed asymmetrically with respect to the virtual axis; , Two connection pad electrodes as a balanced signal terminal, an annular ground electrode, and an annular ground electrode, and a portion formed symmetrically with respect to the virtual axis. Since the capacitance formed by the annular ground conductor can be made equal on both sides of the virtual axis, it is possible to suppress the occurrence of different parasitic capacitances in the two connection pad electrodes as balanced signal terminals. It will be excellent.

  Further, according to the surface acoustic wave device of the present invention, 9) an electrode that is long on the lower surface of the piezoelectric substrate in a direction perpendicular to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate Three or more odd-numbered IDT electrodes each having a plurality of fingers, and reflector electrodes each having a plurality of electrode fingers that are arranged on both sides of the odd-numbered IDT electrodes and that are long in the direction orthogonal to the propagation direction; A surface acoustic wave element comprising a connection pad electrode connected to the IDT electrode and an annular ground electrode surrounding the IDT electrode, reflector electrode and connection pad electrode is formed on the upper surface of the annular surface electrode facing the annular ground electrode. The mounting substrate on which the connection pad conductor facing the grounding conductor and the connection pad electrode and the through-grounding conductor connected to the annular grounding conductor are formed with the lower surface of the piezoelectric substrate facing the upper surface of the mounting substrate. The grounding electrode and the connection pad electrode are respectively bonded and mounted on the annular grounding conductor and the connection pad conductor, and the IDT electrode disposed in the center of the odd number of IDT electrodes has an electrode finger. One of the opposing comb-like electrodes is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the IDT electrode arranged in the center are connected to one comb. The pad electrode for connection is connected to the tooth-like electrode as an unbalanced signal terminal, and the other comb-like electrode is connected to the annular ground electrode. The through-ground conductor is at the center of the IDT electrode disposed in the center. It is formed asymmetric with respect to a virtual axis provided in a direction orthogonal to the propagation direction, and at least one of the annular ground electrode and the annular ground conductor is formed asymmetric with respect to the virtual axis. Therefore, an annular ground electrode and an annular ground conductor, at least one of which is formed asymmetrically with respect to the virtual axis, and a through-ground conductor formed asymmetrically with respect to the virtual axis in the path until the IDT electrode is grounded Since the inductance components are connected through the connection, these inductance components function as a matching circuit, resulting in a low insertion loss and a low VSWR, and an excellent filter passing characteristic. In addition, since the magnitude of such an inductance component can be easily adjusted over a wide range by designing both the through-grounding conductor and the annular grounding electrode and / or the annular grounding conductor, it can function as a desired matching circuit. Thus, a low insertion loss and a low VSWR can be obtained, and a filter having excellent filter passing characteristics can be obtained with high productivity. Furthermore, the through-ground conductor forming the inductance component and at least one of the annular ground electrode and the annular ground conductor are arranged on a virtual axis provided in the direction perpendicular to the propagation direction at the center of the IDT electrode disposed at the center. Since the parasitic capacitance formed by the reflector electrode, the IDT electrode, the through-grounding conductor, the annular grounding electrode, and the annular grounding conductor can be made different on both sides of the virtual axis. Fine adjustment can be made so that the impedance between the two pad electrodes for connection as signal terminals is matched, and the balance becomes higher.

  Further, according to the surface acoustic wave device of the present invention, 10) in the configuration of 9), when the through-grounding conductor is disposed asymmetrically with respect to the virtual axis, the arrangement of the through-grounding conductor is appropriately set. Since the size of the inductance component can be controlled, a function as a desired matching circuit can be easily obtained, and a low insertion loss and a low VSWR can be obtained with excellent filter passing characteristics with high productivity. It will be a thing.

  Further, according to the surface acoustic wave device of the present invention, 11) in the configuration of 9), when the through-grounding conductor has at least one diameter different from the diameter of the other, the diameter of the through-grounding conductor is appropriately set. Since the size of the inductance component can be controlled by this, it is possible to easily obtain a function as a desired matching circuit, and to obtain a low insertion loss and a low VSWR with excellent filter passing characteristics with good productivity. It will be possible.

  According to the surface acoustic wave device of the present invention, 12) In the configuration of 9) described above, when the number of through-grounding conductors is different on both sides of the virtual axis, the number of through-grounding conductors is set appropriately so that the inductance component Therefore, it is possible to easily obtain a function as a desired matching circuit, and to obtain a low insertion loss and a low VSWR with excellent filter passing characteristics with high productivity. Become.

  According to the surface acoustic wave device of the invention, 13) in the configuration of 9), at least one of the annular ground electrode and the annular ground conductor has a portion having a different width so as to be asymmetric with respect to the virtual axis. If it has, the magnitude of the inductance component can be controlled by appropriately setting the width of at least one of the annular ground electrode and the annular ground conductor, so that a desired function as a matching circuit can be easily obtained. Therefore, a low insertion loss and a low VSWR can be obtained with excellent filter pass characteristics and good productivity.

  According to the surface acoustic wave device of the present invention, 14) in any one of the above-mentioned 9) to 13), the through-grounding conductor is a virtual in addition to the group formed asymmetrically with respect to the virtual axis. When a group formed symmetrically with respect to the axis is formed, the group formed symmetrically with respect to the virtual axis is formed by two connection pad electrodes as balanced signal terminals and a through-ground conductor. Since the capacitances to be applied can be made equal on both sides of the virtual axis, and different parasitic capacitances can be prevented from occurring in the two connection pad electrodes as balanced signal terminals, the balance is excellent. .

  According to the surface acoustic wave device of the present invention, 15) in the configurations of 9) to 13), at least one of the annular ground electrode and the annular ground conductor is formed asymmetrically with respect to the virtual axis; , Two connection pad electrodes as a balanced signal terminal, an annular ground electrode, and an annular ground are formed by the portion formed symmetrically with respect to the virtual axis. Since the capacitance formed with at least one of the conductors can be made equal on both sides of the virtual axis, it is possible to suppress the occurrence of different parasitic capacitances in the two connection pad electrodes as balanced signal terminals. Excellent balance.

  According to the surface acoustic wave device of the present invention, 16) In the configurations of 1) to 15) above, the electrode fingers that are long in the direction perpendicular to the propagation direction along the propagation direction are connected to the unbalanced signal terminal. A surface acoustic wave resonator having one IDT electrode provided with a plurality of electrodes and a reflector electrode provided on both sides of the IDT electrode and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction is connected If the surface acoustic wave resonator is manufactured, it is possible to control the position of the attenuation pole caused by the surface acoustic wave resonator by fabricating the surface acoustic wave resonator so that the resonance frequency of the surface acoustic wave resonator becomes a desired value. Therefore, the attenuation pole can be formed at a desired position, and the attenuation characteristic outside the pass band is excellent.

  According to the surface acoustic wave device of the present invention, 17) In the configurations of 1) to 13) above, the balanced signal terminal is provided with a long electrode finger in the direction orthogonal to the propagation direction along the propagation direction. A surface acoustic wave resonator having a plurality of IDT electrodes and reflector electrodes each provided on both sides of the IDT electrode and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction is connected. Since the surface acoustic wave resonator is manufactured so that the resonance frequency of the surface acoustic wave resonator becomes a desired value, the position of the attenuation pole caused by the surface acoustic wave resonator can be controlled. The attenuation pole can be formed at a desired position, and the attenuation characteristics outside the pass band are excellent.

  According to the surface acoustic wave device of the present invention, 18) In the configurations of 1) to 17) above, a plurality of long electrode fingers are provided between the odd number of IDT electrodes in a direction orthogonal to the propagation direction. The insertion reflector electrode is disposed, and the distance between the centers of the adjacent electrode fingers of the insertion reflector electrode gradually decreases from the electrode fingers located at both ends toward the electrode finger located at the center. When the insertion reflector electrode is in use, the amplitude mode can be increased, and the distance between the centers of the adjacent electrode fingers of the insertion reflector electrode is increased from the electrode fingers located at both ends toward the electrode finger located at the center. Since the surface wave can be prevented from being converted into a bulk wave by gradually shortening it, the amplitude mode can be increased without impeding the propagation of the surface acoustic wave. Become.

  According to the communication device of the present invention, 19) since at least one of the reception circuit and the transmission circuit using the surface acoustic wave device according to any one of the above 1) to 18) as a filter means is provided. Since a balun is not required, it is possible to reduce the size and use a surface acoustic wave device having a low insertion loss, a low VSWR, and excellent filter passing characteristics, so that the sensitivity is remarkably improved.

  Hereinafter, the surface acoustic wave device of the present invention will be described in detail with reference to the drawings. In the drawings described below, the same portions are denoted by the same reference numerals, and redundant description is omitted. Further, the size of each electrode, the distance between the electrodes, the number of electrode fingers constituting the IDT electrode, the interval thereof, and the like are schematically illustrated for explanation.

  1 and 2 (a) to 2 (f) show a first embodiment of a surface acoustic wave device according to the present invention.

  FIG. 1 is a plan view showing an example of a surface acoustic wave device according to the first embodiment of the surface acoustic wave device of the present invention. FIG. 2 is a plan view of the surface acoustic wave device of the present invention on which the surface acoustic wave device is mounted. It is a top view which shows an example of the mounting board | substrate in 1 embodiment, (a)-(f) is a top view of each layer which comprises a mounting board | substrate, respectively. FIGS. 3A to 3F and FIGS. 4A to 4F are plan views of respective layers showing other examples of the mounting substrate in the first embodiment of the surface acoustic wave device of the invention. It is.

  As shown in FIG. 1, the surface acoustic wave element 101 in the first embodiment of the surface acoustic wave device of the present invention is in the propagation direction X of the surface acoustic wave propagating on the piezoelectric substrate 100 on the lower surface of the piezoelectric substrate 100. Along with this, three or more odd-numbered IDT electrodes having a plurality of long electrode fingers in a direction orthogonal to the propagation direction X, in this example, three IDT electrodes 201 to 203 and three IDT electrodes 201 to Reflector electrodes 301 and 302 that are arranged on both sides of 203 and have a plurality of long electrode fingers in a direction orthogonal to propagation direction X, and connection pad electrodes 401 to 403 connected to IDT electrodes 201 to 203 The IDT electrodes 201 to 203, the reflector electrodes 301 and 302, and the annular ground electrode 501 surrounding the connection pad electrodes 401 to 403 are disposed.

  In the surface acoustic wave element 101, the IDT electrode 201 disposed in the center of the three IDT electrodes 201 to 203 has an electrode finger and one of the opposing comb-like electrodes divided into two. Connection pad electrodes 402 and 403 are respectively connected as balanced signal terminals, and the IDT electrodes 202 and 203 located on both sides of the IDT electrode 201 disposed in the center are connected to one comb-like electrode. 401 is connected as an unbalanced signal terminal, and the other comb-like electrode is connected to the annular ground electrode 501. In this example, the other comb-like electrodes of the IDT electrodes 202 and 203 are connected to the annular ground electrode 501 via the reflector electrodes 301 and 302, respectively.

  Here, in order to provide the surface acoustic wave element 101 with a balance-unbalance conversion function, the electrode fingers are designed so that the IDT electrodes 202 and 203 are in opposite phases (invert polarities).

  The mounting substrate 600 in the first embodiment of the surface acoustic wave device of the present invention has an annular ground conductor 701 facing the annular ground electrode 501 and a connection pad electrode on the upper surface, as shown in FIG. Connection pad conductors 801 to 803 facing 401 to 403 and through-ground conductors 901 and 902 connected to the annular ground conductor 701 are formed. Here, the through-ground conductors 901 and 902 are formed asymmetrically with respect to the virtual axis Y provided in the direction orthogonal to the propagation direction X at the center of the IDT electrode 201 disposed in the center.

  The mounting substrate 600 has a structure in which a plurality of layers are stacked. In this example, the layers shown in FIGS. 2A to 2F are laminated in order from the upper surface, and the annular ground conductor 701 is connected to the internal ground conductor patterns 910a and 910b through the through ground conductors 901 and 902, The internal ground conductor patterns 910a and 910b are connected to the lower surface ground conductor patterns 920a and 920b through the through ground conductors 901 and 902, respectively. Further, the connection pad conductors 801 to 803 are connected to signal conductor patterns 931 to 933 formed on the lower surface through through grounding conductors 903, respectively. 2A shows the top surface of the mounting substrate 600, FIG. 2B shows the first layer, FIG. 2C shows the first layer shown in FIG. 2B, and FIG. 2D. 2 (d) shows the inner ground conductor pattern forming surface formed between the second layer and FIG. 2 (e), and FIG. 2 (e) shows the lower surface conductor pattern forming surface. It is the top view which shows a lower surface, respectively. In FIG. 2 (f), the solid line portion is a portion where the lower surface ground conductor patterns 920a and 920b and the signal conductor patterns 931 to 933 are exposed.

  The annular ground electrode 501 and the connection pad electrodes 401 to 403 are joined to the annular ground conductor 701 and the connection pad conductors 801 to 803, respectively, with the lower surface of the piezoelectric substrate 100 and the upper surface of the mounting substrate 600 facing each other. The surface acoustic wave device of the present invention can be obtained.

  In the surface acoustic wave element 101, a conductor film is formed on the lower surface of the piezoelectric substrate 100 such as lithium tantalate using a vacuum film forming apparatus or the like, and this is applied to the IDT electrodes 201 to 203 and reflected using a photolithography technique. It is possible to manufacture by the usual manufacturing method of processing into the device electrodes 301 and 302, the connecting pad electrodes 401 to 403, and the annular ground electrode 501. The IDT electrodes 201 to 203 are preferably formed of a conductor having a small mass such as aluminum.

  The mounting substrate 600 is made of an insulating material and used by stacking a plurality of insulating layers. For these insulating layers, for example, ceramics or glass ceramics are used, and a green sheet is produced by molding a slurry in which a metal oxide such as ceramics and an organic binder are homogeneously kneaded with an organic solvent or the like into a sheet shape. After forming patterns of 701, 801 to 803, 910, 920, 931 to 933 and penetrating conductors 901 to 903 with metal conductors, these green sheets are laminated and bonded together to be integrally formed and fired. .

  In order to mount the surface acoustic wave element 101 on the mounting substrate 600, solder paste, Au—Sn is formed on the annular ground electrode 501 and the connection pad electrodes 401 to 403 or the annular ground conductor 701 and the connection pad conductors 801 to 803. A bonding layer made of a paste or the like may be formed by screen printing or the like, arranged so as to face each other, and then bonded by reflow melting.

  In this manner, the IDT electrodes 201 to 203 and the connection pad electrodes 401 to 403 are hermetically sealed by the piezoelectric substrate 100, the mounting substrate 600, the annular ground electrode 501, and the annular ground conductor 701, and the airtightness thereof is kept good. Therefore, it is possible to provide a highly reliable surface acoustic wave device that can be stably operated over a long period of time.

  According to the surface acoustic wave device of the present invention as described above, the through grounding formed asymmetrically with respect to the annular ground electrode 501, the annular ground conductor 701, and the symmetry axis Y in the path until the IDT electrodes 202 and 203 are grounded. Since the inductance components are connected through the conductors 901 and 902, these inductance components function as a matching circuit, resulting in a low insertion loss and a low VSWR, and excellent filter pass characteristics. It will be a thing. In addition, since the magnitude of such an inductance component can be easily adjusted by the design of the through-ground conductors 901 and 902, it can have a function as a desired matching circuit, resulting in a low insertion loss and a low VSWR. A product having excellent filter passage characteristics can be obtained with high productivity. Further, since the through-ground conductors 901 and 902 forming the inductance component are formed asymmetrically with respect to the virtual axis Y, the reflector electrodes 301 and 302 and the IDT electrodes 201 to 203 and the through-ground conductors 901 and 902 Since the formed parasitic capacitance can be made different on both sides of the virtual axis Y, it can be finely adjusted so that the impedance between the two connection pad electrodes 402 and 403 as balanced signal terminals is matched. It becomes a surface acoustic wave device with a high balance. Further, since the reflector electrodes 301 and 302 are grounded via the annular ground electrode 501, the surface acoustic wave reflection efficiency is high and the surface acoustic wave device has a good attenuation characteristic outside the pass band.

  The through-ground conductors 901 and 902 are preferably disposed closer to the connection pad conductor 801 connected to the unbalanced signal terminal than the connection pad conductors 802 and 803 to which the balanced signal terminal is joined. By adopting such a configuration, it is possible to prevent different parasitic capacitances from being generated in the two connection pad electrodes 402 and 403 serving as balanced signal terminals, and therefore the balance can be further improved. .

  Here, as shown in FIG. 2A, the through-grounding conductors 901 and 902 are formed asymmetrically with respect to the virtual axis Y. In this example, the through-grounding conductor on one side across the virtual axis Y When the 901 and the penetrating ground conductor 902 on the other side are disposed asymmetrically with respect to the virtual axis Y, the size of the inductance component can be controlled by appropriately setting the positions of the penetrating ground conductors 901 and 902. Therefore, it is preferable because a desired function as a matching circuit can be easily obtained, and an excellent low insertion loss and low VSWR can be obtained.

  Further, as shown in FIGS. 3A to 3F, the through-ground conductors 901 and 902 have a diameter of the through-ground conductor 902 in this example so that at least one diameter is different from the other diameter. If configured so as to be larger than the diameter of 901, the size of the inductance component can be controlled by appropriately setting the diameter of the through-ground conductors 901 and 902, so that it can easily function as a desired matching circuit. This is preferable because it can provide a low insertion loss and a low VSWR.

  Further, as shown in FIGS. 4A to 4F, the through-ground conductors 901 and 902 may be configured so that the numbers are different on both sides of the virtual axis Y. That is, the number of through grounding conductors 901 formed on one side of the virtual axis Y may be different from the number of through grounding conductors 902 formed on the other side. With such a configuration, the size of the inductance component can be controlled by appropriately setting the number of through-ground conductors 901 and 902, so that a function as a desired matching circuit can be easily obtained. The insertion loss and the VSWR can be made excellent. In addition, since the IDT electrodes 202 and 203 can be reliably grounded by providing a large number of through-ground conductors 901 and 902, a rise in the floor level outside the pass band can be prevented and a surface acoustic wave device having excellent filter characteristics can be obtained. be able to. When a plurality of through ground conductors 901 and 902 are provided, the internal ground conductor patterns 910a and 910b may be provided so as to correspond to the respective through ground conductors 901 and 902, or a plurality of through ground conductors may be provided. Although it is possible to connect and integrate 901 and 902 so as to be connected to one internal ground conductor pattern, as shown in FIG. 4 (c), through-ground conductors 901 and 902 are connected respectively. When the internal ground conductor patterns are separated and a plurality of through ground conductors 902 are connected to one internal ground conductor pattern 910b, the inductance component is independently generated on both sides of the virtual axis Y. The size can be controlled, and the size of the inductance component can be controlled more precisely by setting the shape and area of the internal grounding conductor pattern 910b as appropriate. A function as a circuit can be obtained, and excellent balance, insertion loss, and VSWR can be obtained.

  Further, the through-ground conductors 901 and 902 may have a group formed symmetrically with respect to the virtual axis Y in addition to the group formed asymmetric with respect to the virtual axis Y. With such a configuration, a group formed symmetrically with respect to the virtual axis Y is formed by two connection pad electrodes 401 and 402 and through-grounding conductors 901 and 902 as balanced signal terminals. Since the capacitance can be made equal on both sides of the virtual axis Y, it is possible to suppress the generation of different parasitic capacitances in the two connection pad electrodes 401 and 402 serving as balanced signal terminals, so that the balance is excellent. Can be.

  Next, a second embodiment of the surface acoustic wave device of the present invention will be described with reference to FIGS.

  FIG. 5 is a plan view showing an example of a surface acoustic wave element according to the second embodiment of the surface acoustic wave device of the present invention, and FIG. 6 is a mounting substrate according to the second embodiment of the surface acoustic wave device of the present invention. FIG. 5A is a plan view showing each layer constituting a mounting substrate. FIG. 7 shows another example of the surface acoustic wave device according to the second embodiment of the surface acoustic wave device of the present invention. FIGS. 8 and 9 show the mounting of the surface acoustic wave device according to the second embodiment of the present invention. FIG. 8 and 9, the laminated structure other than the upper surface of the mounting substrate is the same as that shown in FIGS.

  As shown in FIG. 5, the surface acoustic wave element 101 in the second embodiment of the surface acoustic wave device of the present invention is the same as that shown in FIG. 1 except that the annular ground electrode 501 is formed asymmetrically with respect to the virtual axis Y. The basic structure of the surface acoustic wave device 101 according to the first embodiment of the surface acoustic wave device of the present invention is the same as that shown in FIG.

  The mounting substrate 600 in the second embodiment of the surface acoustic wave device of the present invention has a structure in which a plurality of layers are laminated as shown in FIG. The laminated structure is the same as that of FIGS. 2A to 2F except that the asymmetrical points and the through-ground conductors 901 and 902 are arranged symmetrically with respect to the virtual axis Y, and overlapping explanations are given. Omitted.

  The annular ground electrode 501 and the connection pad electrodes 401 to 403 are joined to the annular ground conductor 701 and the connection pad conductors 801 to 803, respectively, with the lower surface of the piezoelectric substrate 100 and the upper surface of the mounting substrate 600 facing each other. The surface acoustic wave device according to the second embodiment can be obtained.

  With such a configuration, the annular ground electrode 501 and the annular ground conductor 701, the through-ground conductor 901, at least one of which is formed asymmetrically with respect to the symmetry axis Y in the path until the IDT electrodes 202 and 203 are grounded. Since the inductance components are connected through 902, these inductance components function as a matching circuit, and as a result, have excellent filter pass characteristics with low insertion loss and low VSWR. Become. In addition, since the magnitude of such an inductance component can be easily adjusted by designing at least one of the annular ground electrode 501 and the annular ground conductor 701, a function as a desired matching circuit can be provided, An insertion loss and a low VSWR can be obtained with excellent filter pass characteristics and good productivity. Furthermore, at least one of the annular ground electrode 501 and the annular ground conductor 701 forming the inductance component is at a center of the IDT electrode 201 disposed in the center with respect to a virtual axis Y provided in a direction orthogonal to the propagation direction X. Therefore, the parasitic capacitance formed by the reflector electrodes 301 and 302 and the IDT electrodes 202 and 203, the annular ground electrode 501 and the annular ground conductor 701 can be made different on both sides of the virtual axis Y. Therefore, it is possible to finely adjust the impedance between the two connection pad electrodes 402 and 403 as balanced signal terminals so as to match each other, so that a good surface acoustic wave device with higher balance can be obtained.

  As shown in FIGS. 5 and 6, at least one of the annular ground electrode 501 and the annular ground conductor 701 is formed to have a portion having a different width so as to be asymmetric with respect to the virtual axis Y. With such a configuration, the magnitude of the inductance component can be controlled by appropriately setting the width of at least one of the annular ground electrode 501 and the annular ground conductor 701. A function can be obtained, and a low insertion loss and a low VSWR can be obtained with excellent filter passing characteristics and high productivity. Further, at least one of the annular ground electrode 501 and the annular ground conductor 701 has a portion formed asymmetrically with respect to the virtual axis Y and a portion formed symmetrically with respect to the virtual axis Y. As a result, two connection pad electrodes 402 and 403 as balanced signal terminals, connection pad conductors 802 and 803 to which these are connected, and an annular ground electrode 501 are formed symmetrically with respect to the virtual axis Y. Further, the capacitance formed by the annular ground conductor 701 can be made equal on both sides of the virtual axis Y, and the occurrence of different parasitic capacitances in the two connection pad electrodes 402 and 403 as balanced signal terminals can be suppressed. Therefore, the balance is excellent.

  Further, as shown in FIGS. 7 and 8, portions of the annular ground electrode 501 and the annular ground conductor 701 formed to have different widths so as to be asymmetric with respect to the virtual axis Y, in this example, the annular ground electrode 501 In addition, L-shaped protruding portions on the inner peripheral surface of the corner portion of the annular ground conductor 701 are connected pad electrodes 402 and 403 as balanced signal terminals and connecting pad conductors 802 and 803 to which these are joined. By providing only on the side close to the connection pad electrode 401 as an unbalanced signal terminal and the connection pad conductor 801 to which it is joined, different parasitic capacitances are generated in the two connection pad electrodes 402 and 403 as balanced signal terminals. Since this can be prevented more reliably, the balance is further improved.

  Furthermore, each electrode pattern of the surface acoustic wave element 101 and the internal structure of the mounting substrate 600 are the same except that at least one of the annular ground electrode 501 and the annular ground conductor 701 is formed asymmetrically with respect to the virtual axis Y. When each conductor pattern is also formed symmetrically with respect to the virtual axis Y, it is possible to more reliably suppress the occurrence of different parasitic capacitances in the two connection pad electrodes 402 and 403 as balanced signal terminals. This is desirable because the balance does not deteriorate.

  Here, in the second embodiment of the surface acoustic wave device of the present invention, the surface acoustic wave element 101 shown in FIGS. 5 and 7 is virtually connected to the through-ground conductors 901 and 902 and the annular ground conductor 701 as shown in FIG. 1 may be mounted on the mounting substrate 600 formed so as to be symmetric with respect to the axis Y, or the annular ground electrode 501 as shown in FIG. The surface acoustic wave element 101 may be mounted on the mounting substrate 600 shown in FIGS.

  In the example shown in FIGS. 5 to 8, only one portion of the annular ground electrode 501 and the annular ground conductor 701 is shown asymmetrically formed with respect to the virtual axis Y. You may provide in several places. For example, on the inner and outer peripheral surfaces of the annular ground electrode 501 and the annular ground conductor 701, a part thereof is removed with a laser so as to provide a large number of fine planar concavo-convex shapes, and the number of concave or convex portions is set to the virtual axis Y. It may be different on both sides. By forming the annular ground electrode 501 and the annular ground conductor 701 asymmetrically on both sides of the virtual axis Y with such a fine planar concavo-convex shape, the magnitude of the inductance component can be precisely adjusted. Further, the planar concavo-convex shape may be formed on the entire inner peripheral surface / outer peripheral surface of the annular ground electrode 501 and the annular ground conductor 701, or may be formed on a part thereof. For example, a fine planar concavo-convex shape is provided in a portion where the annular ground electrode 501 and the annular ground conductor 701 of FIGS. 7 and 8 are formed asymmetrically with respect to the virtual axis Y, that is, a portion protruding in an L shape on the inner peripheral surface Alternatively, the number of concave or convex portions on the annular ground electrode 501 and the annular ground conductor 701 on the side of the connection pad electrodes 402 and 403 and the connection pad conductors 802 and 803 as balanced signal terminals on both sides of the virtual axis Y It is also possible to form them with different values. In the latter case, the capacitance formed by the connection pad electrodes 402 and 403 as the two balanced signal terminals, the connection pad conductors 802 and 803 to which these are joined, the annular ground electrode 501 and the annular ground conductor 701 are provided. By making them different on both sides of the virtual axis Y, it is possible to finely adjust the impedance between the two balanced signal terminals so that the surface acoustic wave device has a good balance.

  Further, in FIG. 6, the annular ground conductors 901 and 902 are used to connect the annular ground electrode 501 and the annular ground conductor 701 to the lower surface ground conductor patterns 920a and 920b, but the laminated surface (outer peripheral surface) of the mounting substrate 600 is used. A caster to be formed may be used.

  In the first embodiment of the surface acoustic wave device of the present invention, only the through-ground conductors 901 and 902 are provided on the virtual axis Y, and in the second embodiment, at least one of the annular ground electrode 501 and the annular ground conductor 701 is provided on the virtual axis Y. Although an example of being asymmetric with respect to the above has been described, by combining these, the through-ground conductors 901 and 902 are formed asymmetrically with respect to the virtual axis Y, and the annular ground electrode 701 and the annular ground conductor 701 are formed. If the configuration is such that at least one of them is formed asymmetrically with respect to the virtual axis Y (hereinafter referred to as the third embodiment of the surface acoustic wave device of the present invention), the IDT electrodes 202 and 203 are grounded. Since the magnitude of the inductance component added to the path to be processed can be easily controlled over a wider range, the function as a desired matching circuit can be provided, and low insertion loss and low It can be those excellent in SWR next filter pass characteristics.

  In such a surface acoustic wave device, in order to form the penetrating ground conductors 901 and 902 asymmetrically with respect to the virtual axis Y, the penetrating ground conductors 901 and 902 may be disposed asymmetrically with respect to the virtual axis Y. However, it may be formed such that at least one diameter is different from the diameter of the other, the number may be different on both sides of the virtual axis Y, or asymmetric with respect to the virtual axis Y. In addition to the group, it may be formed so as to have a group formed symmetrically with respect to the virtual axis Y. In particular, when a large number of through-ground conductors 901 and 902 are provided and arranged so as to be asymmetric with respect to the virtual axis Y, the IDT electrodes 201 to 203 can be reliably grounded. The rise in the surface acoustic wave device can be reliably suppressed, and a surface acoustic wave device having excellent filter characteristics can be obtained, which is preferable.

  In order to form at least one of the annular ground electrode 501 and the annular ground conductor 701 asymmetrically with respect to the virtual axis Y, at least one of the annular ground electrode 501 and the annular ground conductor 701 is asymmetric with respect to the virtual axis Y. It may be formed so as to have a portion with a different width, or it may have a portion formed symmetrically with respect to the virtual axis Y and a portion formed symmetrically with respect to the virtual axis Y. It may be formed.

  Further, at least one of the through-ground conductors 901 and 902 and the annular ground electrode 501 and the annular ground conductor 701 is formed asymmetrically with respect to the virtual axis Y as connection pad electrodes 402 and 403 as balanced signal terminals. Is formed closer to the connection pad electrode 401 as an unbalanced signal terminal, that is, when formed on the connection pad electrode 401 side with the IDT electrodes 201 to 203 interposed therebetween, Since it is possible to prevent the generation of different parasitic capacitances in the connection pad electrodes 402 and 403, it is preferable because the balance is excellent.

  Thus, according to the third embodiment of the surface acoustic wave device of the present invention, at least one of the annular ground electrode 501, the annular ground conductor 701, and the through ground conductors 901 and 902 is asymmetric with respect to the virtual axis Y. By forming, an inductance component can be added to the path until the IDT electrodes 202 and 203 are grounded without affecting the connection pad electrodes 402 and 403 as balanced signal terminals, and this inductance component Therefore, it is possible to provide a surface acoustic wave device having a low insertion loss and a low VSWR and excellent filter passing characteristics.

  Next, modified examples of the first to third embodiments of the surface acoustic wave device of the present invention as described above will be described with reference to FIGS. 10 to 12 are plan views showing modifications of the surface acoustic wave element 101 in the surface acoustic wave device of the invention. Hereinafter, based on the structure of the surface acoustic wave element 101 shown in FIG. 1, only the parts changed from the above-described surface acoustic wave device of the present invention will be described, and redundant descriptions regarding similar parts will be omitted.

  In the surface acoustic wave device of the present invention, as shown in FIG. 10, the connection pad electrode 401 as the unbalanced signal terminal of the surface acoustic wave element 101 is connected to the IDT electrodes 202 and 203 and the connection pad electrode 401 in this example. Between one IDT electrode 1101 having a plurality of long electrode fingers in the direction orthogonal to the propagation direction X along the propagation direction X, and disposed on both sides of the IDT electrode 1101 A surface acoustic wave resonator 1001 having reflector electrodes 1201 and 1202 provided with a plurality of long electrode fingers in a direction orthogonal to the direction X may be connected. With this configuration, the surface acoustic wave resonator 1101 is manufactured so that the resonance frequency of the surface acoustic wave resonator 1101 has a desired value, so that the attenuation pole caused by the surface acoustic wave resonator 1101 can be reduced. Since the position can be controlled, the attenuation pole can be formed at a desired position, and the attenuation characteristic outside the pass band can be excellent. The resonance frequency of the surface acoustic wave resonator 1101 can be controlled by adjusting the magnitude of the capacitance of the IDT electrode 1101 and the inductance of the path until the IDT electrode 1101 is grounded.

  Furthermore, in the surface acoustic wave device of the present invention, as shown in FIG. 11, the connection pad electrodes 402 and 403 as balanced signal terminals of the surface acoustic wave element 101 are connected to the IDT electrode 201 and the connection pad electrode 402 in this example. , 403 in series, along the propagation direction X, one IDT electrode 1101 having a plurality of long electrode fingers in a direction orthogonal to the propagation direction X, and on both sides of the IDT electrode 1101 Surface acoustic wave resonators 1002 and 1003 having reflector electrodes 1201 and 1202 that are respectively disposed and have a plurality of long electrode fingers in a direction orthogonal to the propagation direction X may be connected. With such a configuration, the surface acoustic wave resonators 1102 and 1103 are manufactured so that the resonance frequency of the surface acoustic wave resonators 1102 and 1103 has a desired value. Therefore, the attenuation pole can be formed at a desired position, and the attenuation characteristic outside the passband can be excellent.

  Here, if the surface acoustic wave resonators 1001 to 1003 are connected in series to the connection pad electrodes 401 to 403, they are attenuated sharply on the low frequency side in the vicinity of the resonance frequency compared to the high frequency side. By forming an attenuation pole on the high-frequency side, the attenuation characteristics on the high-frequency side of the passband can be improved, and if connected in parallel, it is steeper on the high-frequency side near the resonance frequency than on the low-frequency side. Therefore, the attenuation characteristic on the low band side of the pass band can be improved by forming the attenuation pole on the low band side of the pass band. For this reason, a connection method may be appropriately selected according to a desired attenuation characteristic. Further, by connecting a surface acoustic wave resonator having the same structure made of the same material to the connection pad electrodes 402 and 403 as balanced signal terminals, different parasitics are generated in the two connection pad electrodes 402 and 403 as balanced signal terminals. Generation of a capacity can be suppressed, and a surface acoustic wave device with excellent balance can be obtained.

  Furthermore, in the surface acoustic wave device of the present invention, as shown in FIG. 12, an odd number of surface acoustic wave elements 101, in this example, three IDT electrodes 201 to 203 are orthogonal to the propagation direction X. Insertion reflector electrodes 1301 and 1302 having a plurality of electrode fingers long in the direction are disposed, and the distance between the centers of the adjacent electrode fingers of the insertion reflector electrodes 1301 and 1302 is the electrode fingers located at both ends. It is good also as a structure which becomes gradually short toward the said electrode finger located in a center part. With such a configuration, the amplitude mode can be increased by the insertion reflectors 1301 and 1302, and the distance between the centers of the adjacent electrode fingers of the insertion reflector electrodes 1301 and 1302 is the electrode finger positioned at both ends. Since it is possible to prevent the surface acoustic wave from being converted into a bulk wave by gradually shortening from the electrode finger to the electrode finger located in the center, increase the amplitude mode without disturbing the propagation of the surface acoustic wave Therefore, a surface acoustic wave device with a wide pass band can be realized.

  Such a surface acoustic wave element 101 shown in FIGS. 10 to 12 may be mounted on a mounting substrate 600 as shown in FIGS. As shown in FIG. 7, the annular ground electrode 501 may be formed asymmetrically with respect to the virtual axis Y.

  In addition, the surface acoustic wave device of the present invention can be applied to a communication device. That is, at least one of a receiving circuit and a transmitting circuit using the surface acoustic wave device of the present invention as a filter means is provided. For example, the transmission signal output from the transmission circuit is put on the carrier frequency by the mixer, the unnecessary signal is attenuated by the band pass filter, and then the transmission signal is amplified by the power amplifier and transmitted from the antenna through the duplexer. A communication device equipped with a transmission circuit capable of receiving signals, receiving received signals with an antenna, amplifying the received signals that passed through the duplexer with a low-noise amplifier, and then attenuating unnecessary signals with a bandpass filter, The surface acoustic wave device of the present invention can be applied to various filters in a communication device including a receiving circuit that separates a signal and extracts the signal. If the surface acoustic wave device of the present invention is employed, communication with excellent sensitivity is possible. An apparatus can be provided.

  As described above, according to the communication device of the present invention, it is possible to provide a communication device such as an excellent communication device that has a reception circuit and a transmission circuit each having an excellent surface acoustic wave device and whose sensitivity is remarkably good.

  The surface acoustic wave device and the communication device of the present invention are not limited to the above-described embodiments, and can be changed and improved without departing from the gist of the present invention. For example, two or more types of IDT electrodes having different pass bands may be provided in a region in the annular ground electrode 501, and further, the annular ground electrode may be provided so as to individually surround the two or more types of IDT electrodes.

  Specific examples of the present invention will be described.

  Specifically, the surface acoustic wave element 101 shown in FIG. 10 is manufactured so as to function as a surface acoustic wave filter having a center frequency in the 1800 MHz band, and the surface acoustic wave element 101 is mounted on the mounting substrate 600 shown in FIG. The surface acoustic wave device of the present invention was fabricated.

First, an IDT electrode 201 to 203, 1101, reflector electrodes 301, 302, 1201, 1202, and a connection pad electrode 401 are formed on a LiTaO ₃ single crystal piezoelectric substrate 100 having a 38.7 ° Y-cut in the X direction. A fine electrode pattern made of Al (99 mass%)-Cu (1 mass%) of ˜403 and the annular ground electrode 501 was formed.

  The pattern was produced by photolithography using a sputtering apparatus, a reduction projection exposure machine (stepper), and an RIE (Reactive Ion Etching) apparatus.

  First, the piezoelectric substrate 100 was ultrasonically cleaned with acetone / IPA (isopropyl alcohol) or the like to remove organic components. Next, after sufficiently drying the piezoelectric substrate 100 by a clean oven, the electrodes 201 to 203, 301, 302, 401 to 403, 501, 1101, 1201, and 1202 were formed. A sputtering apparatus is used to form the electrodes 201 to 203, 301, 302, 401 to 403, 501, 1101, 1201, and 1202, and a material composed of an Al (99 mass%)-Cu (1 mass%) alloy is used. Used to form a thickness of about 0.20 μm.

  Next, a photoresist is formed by spin coating to a thickness of about 0.5 μm, patterned into a desired shape by a reduction projection exposure apparatus (stepper), and an unnecessary portion of the photoresist is dissolved in an alkaline developer by a developing apparatus. After the desired pattern is exposed, the electrode film is etched by the RIE apparatus, and the electrodes 201 to 203, 301, 302, 401 to 403, 501 of the surface acoustic wave element 101 constituting the surface acoustic wave filter are formed. 1101, 1201, and 1202 patterns were obtained.

Thereafter, a protective film was formed on a predetermined region of each of the electrodes 201 to 203, 301, 302, 401 to 403, 501, 1101, 1201, and 1202. That formed by CVD (Chemical Vapor Deposition) apparatus, a thickness of about 0.02μm to SiO ₂ on the pattern and the piezoelectric substrate 100 of each electrode 201～203,301,302,401～403,501,1101,1201,1202 did. Thereafter, the photoresist was patterned by photolithography, and the flip-chip window opening was etched at the positions where the electrodes 401 to 403 and 501 were formed using an RIE apparatus or the like. Thereafter, using a sputtering apparatus, a layer made of Al is formed to a thickness of about 1.0 μm, and Al and photoresist except for the positions where the electrodes 401 to 403 and 501 are formed are simultaneously removed by a lift-off method. A pad for forming flip chip bumps on ˜403,501 was completed.

  Next, flip-chip bumps made of solder were formed on the pads using a screen printing apparatus. The bump diameter on the connection pad electrodes 401 to 403 was about 80 μm, the height was about 30 μm, and the bump height on the annular ground electrode 501 was about 30 μm.

  Next, the piezoelectric substrate 100 was diced along dicing lines and divided into individual surface acoustic wave elements 101.

  Next, a mounting substrate 600 shown in FIG. 2 was produced. That is, in order to produce LTCC (Low Temperature Co-fired Ceramics), a green sheet is produced by molding a slurry in which a metal oxide and an organic binder are homogeneously kneaded with an organic solvent or the like into a sheet shape, After forming the ring ground conductor 701, connection pad conductors 801 to 803, through ground electrodes 901 to 903, internal ground conductors 910a and 910b, bottom ground conductors 920a and 920b, and signal conductor patterns 931 to 933 at desired positions These green sheets were laminated and pressure-bonded to form an integral body and fired. The size of the mounting substrate 600 was 2.5 × 2.0 mm square.

  Here, the annular ground conductor 701 and the connection pad conductors 801 to 803 are formed so as to correspond to the annular ground electrode 501 and the connection pad electrodes 401 to 403 of the surface acoustic wave element 101. Further, the annular ground conductor 701, the connecting pad conductors 801 to 803, the internal ground conductors 910a and 910b, the bottom ground conductors 920a and 920b, and the signal conductor patterns 931 to 933 are formed by screen printing to a thickness of about 1 μm using Ag. Formed. The through-ground electrodes 901 to 903 were formed by forming through holes by die punching and filling with Ag-based conductor paste.

  The surface acoustic wave element 101 formed in this way is arranged with the lower surface (electrode formation surface) of the piezoelectric substrate 100 and the upper surface of the mounting substrate 600 facing each other by a flip chip mounting apparatus, and at 240 ° C. in a reflow furnace. The annular ground electrode 501 and the connection pad electrodes 401 to 403, the annular ground conductor 701 and the connection pad conductors 801 to 803 are electrically connected to each other by reflow melting for 5 minutes and joining them with bumps made of solder. The IDT electrodes 201 to 203 and 1101 were hermetically sealed by connecting the annular ground electrode 501 and the annular ground conductor 701 together to complete the surface acoustic wave device.

  As a reference example, a surface acoustic wave element 101 in which an annular ground electrode 501 is formed symmetrically with respect to the symmetry axis Y as shown in FIG. 1 is used as a through-ground conductor 901, 902 and an annular ground as shown in FIG. A surface acoustic wave device mounted on a mounting substrate 600 in which the conductor 701 was formed symmetrically with respect to the symmetry axis Y was manufactured in the same process using the same material as in the above-described example.

  Next, the characteristics of the surface acoustic wave device in Examples and Reference Examples were measured. A signal of 0 dBm was input, and measurement was performed under the conditions of a frequency of 1640 MHz to 2440 MHz and a measurement point of 800 points. The number of samples was 30, and a multi-port network analyzer E5071A manufactured by Agilent Technologies was used as a measuring instrument.

  In the embodiment, the through-ground conductors 901 and 902 are arranged asymmetrically with respect to the virtual axis Y as shown in FIG. 2, and the magnitude of the inductance component connected to the path until the IDT electrodes 202 and 203 are grounded is set. 0.3 nH. FIGS. 13 to 15 are diagrams showing the frequency dependence of the transmission characteristics of the input signal in the surface acoustic wave device of the example manufactured in this way and the surface acoustic wave device of the reference example. 13 to 15, the solid line shows the characteristics of the surface acoustic wave device of the example, and the broken line shows the characteristics of the surface acoustic wave device of the reference example.

  FIG. 13 is a diagram showing the frequency dependence of insertion loss representing transmission characteristics in the vicinity of the passband (1780 MHz to 1920 MHz), where the horizontal axis represents frequency (MHz) and the vertical axis represents insertion loss (dB). As is apparent from FIG. 13, it was found that the surface acoustic wave device of the example had lower (less) insertion loss and improved filter pass characteristics than the surface acoustic wave device of the reference example.

  FIG. 14 is a diagram showing the frequency dependence of the VSWR in the vicinity of the passband (1750 MHz to 1950 MHz), where the horizontal axis is frequency (MHz) and the vertical axis is VSWR. As is clear from FIG. 14, it was found that the surface acoustic wave device of the example had a lower VSWR and improved the filter passing characteristics than the surface acoustic wave device of the reference example.

  In this configuration, an inductance component is connected to a path until the IDT electrodes 202 and 203 are grounded (that is, connected to the lower surface ground conductor 920 of the surface acoustic wave device) by adopting a configuration like the embodiment of the present invention. This is because an inductance component is connected to the ground terminal), and this inductance component performs the same function as the matching circuit.

  Further, FIG. 15A is an amplitude balance at 1750 MHz to 1950 MH, and FIG. 15B is a diagram showing the frequency dependence of the phase balance at 1750 MHz to 2000 MH. The horizontal axis represents the frequency (MHz) and the vertical axis. FIG. 15A shows the amplitude balance (dB), and FIG. 15B shows the phase balance (deg). As is apparent from FIGS. 15A and 15B, the surface acoustic wave device according to the embodiment of the present invention is good in that the degree of balance does not deteriorate even when compared with the surface acoustic wave device according to the reference example. It was confirmed. This is presumably because different parasitic capacitances can be suppressed from being added to the connection pad electrodes 402 and 403 as balanced signal terminals of the surface acoustic wave device shown in the embodiment of the present invention.

  Thus, according to the surface acoustic wave device of the present invention, it was found that the balance was good, the insertion loss was low, the VSWR was low, that is, the filter passing characteristics were excellent.

  In addition, as a result of measuring the transmission characteristic by changing the magnitude of the inductance component connected to the path until the IDT electrodes 202 and 203 of the surface acoustic wave device of the example are grounded, the magnitude of the inductance component is 0.5 nH. It has been found that the degree of balance tends to be deteriorated with the above, and is preferably in the range of 0.1 to 0.3 nH.

It is a top view which shows an example of the surface acoustic wave element in 1st Embodiment of the surface acoustic device of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows an example of the mounting board | substrate in 1st Embodiment of the surface acoustic wave apparatus of this invention, (a)-(f) is a top view of each layer which each comprises a mounting board | substrate. (A)-(f) is a top view of each layer which shows the other example of the board | substrate for mounting in 1st Embodiment of the surface acoustic wave apparatus of this invention, respectively. (A)-(f) is a top view of each layer which shows the other example of the board | substrate for mounting in 1st Embodiment of the surface acoustic wave apparatus of this invention, respectively. It is a top view which shows an example of the surface acoustic wave element in 2nd Embodiment of the surface acoustic wave apparatus of this invention. It is a top view which shows an example of the mounting board | substrate in 2nd Embodiment of the surface acoustic wave apparatus of this invention, (a)-(f) is a top view of each layer which each comprises a mounting board | substrate. It is a top view which shows the other example of the surface acoustic wave element in 2nd Embodiment of the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of the board | substrate for mounting in 2nd Embodiment of the surface acoustic wave apparatus of this invention. It is a top view which shows the further another example of the mounting board | substrate in 2nd Embodiment of the surface acoustic wave apparatus of this invention. It is a top view which shows an example of the modification of the surface acoustic wave element in the surface acoustic wave apparatus of this invention. It is a top view which shows the other example of the modification of the surface acoustic wave element in the surface acoustic wave apparatus of this invention. It is a top view which shows the further another example of the modification of the surface acoustic wave element in the surface acoustic wave apparatus of this invention. It is a diagram which shows the frequency dependence of the insertion loss showing the transmission characteristic of passband vicinity of the surface acoustic wave apparatus of this invention. It is a diagram which shows the frequency dependence of VSWR near the pass band of the surface acoustic wave device of the present invention. (A) is an amplitude balance of the surface acoustic wave device of the present invention, and (b) is a diagram showing the frequency dependence of the phase balance of the surface acoustic wave device of the present invention. It is a top view which shows the conventional surface acoustic wave filter with an unbalance-balance conversion function. It is a top view which shows the other example of the conventional surface acoustic wave element with an unbalance-balance conversion function. FIG. 18 is a diagram showing the frequency dependence of insertion loss of the surface acoustic wave filter and the surface acoustic wave element shown in FIGS. 16 and 17. FIG. 18 is a diagram showing the frequency dependence of VSWR of the surface acoustic wave filter and the surface acoustic wave element shown in FIGS. 16 and 17. (A) of the surface acoustic wave filter and surface acoustic wave element shown in FIGS. 16 and 17 are diagrams showing the frequency dependence of the amplitude balance, and (b) are diagrams showing the frequency dependence of the phase balance.

Explanation of symbols

100 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Piezoelectric substrate
101 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Surface acoustic wave device
201, 202, 203, 1101 ... IDT electrodes
301,302 ... Reflector electrode
401 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pad electrode for connection (unbalanced signal terminal)
402, 403 ... Pad electrode for connection (balanced signal terminal)
501 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Annular ground electrode
600 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mounting board
701 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Round ground conductor
801 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pad conductor for connection
802,803 ・ ・ ・ ・ ・ ・ ・ ・ Pad conductor for connection
901, 902 ... Penetration ground conductor
1001, 1002, 1003... Surface acoustic wave resonators
1301, 1302 ... Insert reflector electrode

Claims (12)

Three or more odd-numbered IDT electrodes having a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate on the lower surface of the piezoelectric substrate; A reflector electrode provided on each side of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction, a connection pad electrode connected to the IDT electrode, A surface acoustic wave device comprising an IDT electrode, a reflector electrode, and an annular ground electrode surrounding the connection pad electrode, an annular ground conductor facing the annular ground electrode on the upper surface, and the connection pad electrode the opposing connection pad conductor and a mounting substrate having a plurality of through ground conductor having one end connected to the annular ground conductor is formed, and the upper surface of the lower surface and the mounting substrate of the piezoelectric substrate The IDT electrode disposed in the center of the odd number of IDT electrodes, wherein the annular ground electrode and the connection pad electrode are bonded to and mounted on the annular ground conductor and the connection pad conductor, respectively. The IDT electrode disposed at the center of the comb-like electrode having the electrode fingers is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the first electrode have one of the comb-like electrodes connected to the connection pad electrode as an unbalanced signal terminal and the other of the comb-like electrodes connected to the annular ground electrode. ,
The plurality of through-grounding conductors are formed asymmetrically with respect to a virtual axis provided in a direction orthogonal to the propagation direction at the center of the IDT electrode disposed at the center, and the plurality of asymmetrically formed plurality The diameter of the through-grounding conductor is different from the diameter of the through-grounding conductor disposed on one side of the virtual axis, and the other end of the through-grounding conductor is the mounting substrate. The surface acoustic wave device is connected to a lower surface ground conductor pattern provided on the lower surface of the surface acoustic wave device. Three or more odd-numbered IDT electrodes having a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate on the lower surface of the piezoelectric substrate; A reflector electrode provided on each side of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction, a connection pad electrode connected to the IDT electrode, A surface acoustic wave device comprising an IDT electrode, a reflector electrode, and an annular ground electrode surrounding the connection pad electrode, an annular ground conductor facing the annular ground electrode on the upper surface, and the connection pad electrode A mounting substrate on which a plurality of through-ground conductors having opposing connection pad conductors and one end connected to the annular ground conductor are formed on the lower surface of the piezoelectric substrate and the upper surface of the mounting substrate. The IDT electrode disposed in the center of the odd number of IDT electrodes, wherein the annular ground electrode and the connection pad electrode are bonded to and mounted on the annular ground conductor and the connection pad conductor, respectively. Have the electrode fingers respectively
One of the opposing comb-like electrodes is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal, and the IDT electrodes located on both sides of the IDT electrode disposed in the center Is connected to one of the comb-shaped electrodes as the unbalanced signal terminal and the other comb-shaped electrode is connected to the annular ground electrode,
The plurality of through-grounding conductors are formed asymmetrically with respect to a virtual axis provided in a direction orthogonal to the propagation direction at the center of the IDT electrode disposed at the center, The surface acoustic wave device according to claim 1 , further comprising a group formed symmetrically with respect to the virtual axis in addition to a group formed asymmetrically with respect to the virtual axis . 3. The surface acoustic wave device according to claim 1, wherein the plurality of through-grounding conductors have different numbers on both sides of the virtual axis . Three or more odd-numbered IDT electrodes having a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate on the lower surface of the piezoelectric substrate; A reflector electrode provided on each side of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction, a connection pad electrode connected to the IDT electrode, A surface acoustic wave device comprising an IDT electrode, a reflector electrode, and an annular ground electrode surrounding the connection pad electrode, an annular ground conductor facing the annular ground electrode on the upper surface, and the connection pad electrode A mounting substrate on which a plurality of through-ground conductors having one end connected to the connecting pad conductor and the annular ground conductor are formed, the lower surface of the piezoelectric substrate and the upper surface of the mounting substrate The IDT electrode disposed in the center of the odd number of IDT electrodes, wherein the annular ground electrode and the connection pad electrode are bonded to and mounted on the annular ground conductor and the connection pad conductor, respectively. The IDT electrode disposed at the center of the comb-like electrode having the electrode fingers is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the first electrode have one of the comb-like electrodes connected to the connection pad electrode as an unbalanced signal terminal and the other of the comb-like electrodes connected to the annular ground electrode. ,
The plurality of through-grounding conductors are formed asymmetrically with respect to a virtual axis provided in a direction orthogonal to the propagation direction at the center of the IDT electrode disposed at the center, and the plurality of asymmetrically formed plurality The diameter of the through-ground conductor of the one disposed on one side of the virtual axis is different from the diameter of the one disposed on the other side of the virtual axis, and the other end of the through-ground conductor is connected to the mounting substrate. Connected to the bottom ground conductor pattern provided on the bottom surface,
At least one of the virtual axis surface acoustic wave device you characterized in that it is formed asymmetrically with respect to the annular ground electrode and the annular grounding conductor. Three or more odd-numbered IDT electrodes having a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction of the surface acoustic wave propagating on the piezoelectric substrate on the lower surface of the piezoelectric substrate; A reflector electrode provided on each side of the odd number of IDT electrodes and provided with a plurality of long electrode fingers in a direction orthogonal to the propagation direction, a connection pad electrode connected to the IDT electrode, A surface acoustic wave device comprising an IDT electrode, a reflector electrode, and an annular ground electrode surrounding the connection pad electrode, an annular ground conductor facing the annular ground electrode on the upper surface, and the connection pad electrode A mounting substrate on which a plurality of through-ground conductors having one end connected to the connecting pad conductor and the annular ground conductor are formed, the lower surface of the piezoelectric substrate and the upper surface of the mounting substrate The IDT electrode disposed in the center of the odd number of IDT electrodes, wherein the annular ground electrode and the connection pad electrode are bonded to and mounted on the annular ground conductor and the connection pad conductor, respectively. The IDT electrode disposed at the center of the comb-like electrode having the electrode fingers is divided into two, and the connection pad electrode is connected to each as a balanced signal terminal. The IDT electrodes located on both sides of the first electrode have one of the comb-like electrodes connected to the connection pad electrode as an unbalanced signal terminal and the other of the comb-like electrodes connected to the annular ground electrode. ,
The plurality of through-grounding conductors are formed asymmetrically with respect to a virtual axis provided in the direction orthogonal to the propagation direction at the center of the IDT electrode disposed at the center, and the plurality of through-grounding conductors are , in addition to the group formed asymmetrically with respect to the virtual axis, have a group that is formed symmetrically with respect to the imaginary axis, the other end of the through grounding conductor, the lower surface of the mounting substrate Connected to the bottom ground conductor pattern provided in
At least one of the annular ground electrode and the annular ground conductor is formed asymmetrically with respect to the virtual axis . The surface acoustic wave device according to claim 4 , wherein the number of the through-grounding conductors is different on both sides of the virtual axis . 6. The surface acoustic wave device according to claim 4 , wherein at least one of the annular ground electrode and the annular ground conductor has a portion having a different width so as to be asymmetric with respect to the virtual axis. . At least one of the annular ground electrode and the annular ground conductor has a portion formed asymmetrically with respect to the virtual axis and a portion formed symmetrically with respect to the virtual axis. The surface acoustic wave device according to claim 4 or 5 . A single IDT electrode provided with a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction and the unbalanced signal terminal are disposed on both sides of the IDT electrode, respectively. 9. The elasticity according to claim 1 , wherein a surface acoustic wave resonator having a reflector electrode having a plurality of long electrode fingers in a direction orthogonal to the direction is connected. Surface wave device. A single IDT electrode having a plurality of long electrode fingers in the direction orthogonal to the propagation direction along the propagation direction and the balanced signal terminal are respectively disposed on both sides of the IDT electrode, and the propagation direction 10. A surface acoustic wave resonator according to claim 1, wherein said surface acoustic wave resonator is connected to a reflector electrode having a plurality of long electrode fingers in a direction perpendicular to the surface. Wave equipment. An insertion reflector electrode having a plurality of long electrode fingers in a direction orthogonal to the propagation direction is disposed between the odd number of IDT electrodes, and an electrode finger adjacent to the insertion reflector electrode is disposed. The elastic surface according to any one of claims 1 to 10, wherein a center-to-center distance is gradually shortened from the electrode fingers located at both ends toward the electrode fingers located at the center. Wave equipment. 12. A communication apparatus comprising at least one of a receiving circuit and a transmitting circuit using the surface acoustic wave device according to claim 1 as a filter unit .

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