CN106160689B - Wireless communication device and filter thereof - Google Patents

Abstract

A wireless communication device and a filter thereof. The filter has an input end and an output end, and includes a first energy storage element, a first and a second series resonant circuit, and a first and a second parallel resonant circuit. The first and the second series resonant circuits each include a first capacitor and a first inductor connected in series. The first and the second parallel resonant circuits each include a second capacitor and a second inductor connected in parallel. The first series resonant circuit and the first parallel resonant circuit are stacked between the first end of the first energy storage element and the ground end, and the second series resonant circuit and the second parallel resonant circuit are stacked between the second end of the first energy storage element and the ground end.

Description

Wireless communication device and its filter

technical field

The present invention relates to a wireless communication device and its filter, and in particular to a wireless communication device with parallel dual radio frequency operation and its filter.

Background technique

In recent years, WLANs conforming to the IEEE 802.11ac communication standard utilize Concurrent Dual-Radio Technology (Concurrent Dual-Radio Technology) to increase the number of user connections. Among them, the IEEE 802.11ac communication standard can use a license-free National Information Infrastructure (Unlicensed National Information Infrastructure, UNII for short) frequency band for communication. Under parallel dual radio operation, two transceivers in the wireless communication device can simultaneously operate in adjacent UNII-1 (5.17˜5.25 GHz) frequency bands and UNII-3 (5.735˜5.815 GHz) frequency bands. In addition, in order to avoid the mutual interference of the wireless communication device between the above two frequency bands, the wireless communication device must be equipped with a filter with a steep filter curve and high isolation.

Generally speaking, thin-film bulk acoustic resonator (FBAR) and dielectric resonator filter (DRF) are often designed to have a steep filter curve or high isolation filter. However, the above-mentioned filter must be manufactured by a special process, so it is expensive and has a relatively large area. In addition, most of the existing technologies increase the attenuation of the filter by increasing the order of the filter. However, as the order of the filter increases, the size of the filter will increase, and the filter will have greater insertion loss and poor amplitude flatness. In other words, existing filters tend to increase the production cost of the wireless communication device and limit the miniaturization of the wireless communication device.

Contents of the invention

The present invention provides a wireless communication device and its filter. A series resonant circuit and a parallel resonant circuit are respectively stacked at both ends of an energy storage element to form a filter. In this way, the filter will help reduce the production cost of the wireless communication device, and contribute to the miniaturization of the wireless communication device.

The filter of the present invention has an input terminal and an output terminal, and includes a first energy storage element, first and second series resonant circuits and first and second parallel resonant circuits. Each of the first and second series resonant circuits includes a first capacitor and a first inductor connected in series. The first and second parallel resonant circuits each include a second capacitor and a second inductor connected in parallel with each other, and the first series resonant circuit and the first parallel resonant circuit are cascaded between the first end of the first energy storage element and the ground end. , to form a filter with a passband and a stopband.

The wireless communication device of the present invention includes a first transceiver, a second transceiver, a first filter and a second filter. The first transceiver is electrically connected to the first antenna through at least one first signal terminal. The second transceiver is electrically connected to the second antenna through at least one second signal terminal. The first filter includes a first passband and a first stopband, and is arranged between the at least one first signal terminal and the first antenna. The second filter includes a second passband and a second stopband, and is arranged between the at least one second signal terminal and the second antenna. The first passband is the same as the second stopband, and the first stopband is the same as the second passband. The first filter and the second filter each have an input end and an output end, and each include a first energy storage element, a first and a second series resonant circuit and a first and a second parallel resonant circuit. Each of the first and second series resonant circuits includes a first capacitor and a first inductor connected in series. The first and second parallel resonant circuits each include a second capacitor and a second inductor connected in parallel. The first series resonant circuit and the first parallel resonant circuit are cascaded between the first end of the first energy storage element and the ground end. The second series resonant circuit and the second parallel resonant circuit are cascaded between the second end of the first energy storage element and the ground end.

Based on the above, the present invention connects the first series resonant circuit and the first parallel resonant circuit at the first end of the first energy storage element, and connects the second series resonant circuit and the second parallel resonant circuit at the second end of the first energy storage element. A resonant circuit is connected in parallel to thereby form a filter. In this way, the filter will help reduce the production cost of the wireless communication device, and contribute to the miniaturization of the wireless communication device.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail with reference to the accompanying drawings.

Description of drawings

FIG. 1 is a schematic circuit diagram of a filter according to an embodiment of the invention.

FIG. 2 is a schematic diagram illustrating the frequency response of the filter in FIG. 1 .

FIG. 3 is a schematic circuit diagram of a filter according to another embodiment of the invention.

FIG. 4 is a schematic diagram illustrating the frequency response of the filter in FIG. 3 .

FIG. 5 is a schematic layout diagram of a filter according to an embodiment of the invention.

FIG. 6 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention.

FIG. 7 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention.

FIG. 8 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating the frequency response of the filter in FIG. 8 .

FIG. 10 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating the frequency response of the filter in FIG. 10 .

FIG. 12 is a block diagram of a wireless communication device according to an embodiment of the invention.

FIG. 13 is a block diagram of a wireless communication device according to another embodiment of the present invention.

[Description of Reference Signs]

100, 300, 600, 700, 800, 1000: filter

110, 310, 610, 710: energy storage elements

120, 130, 320, 330, 620, 720, 810, 820, 1010, 1020: series resonant circuit

140, 150, 630, 730: parallel resonant circuit

C11, C12, C21, C22, C3, C31, C32, C61, C62, C71～C73, C81, C82, C101, C102: capacitance

L11, L12, L21, L22, L3, L31, L32, L61～L63, L71, L72, L81, L82, L101, L102: inductance

IN: input terminal

OUT: output terminal

210, 410, 910, 1110: Passband

220, 420, 920, 1120: stop band

230, 430, 930, 940, 1130, 1140: filter frequency band

P21, P22, P41, P42: turning points

511～519: chip type components

520: Substrate

521: surface

530, 540: conductive thread

550: conductive surface

1200, 1300: wireless communication device

1211, 1212: Transceiver

1221, 1222: power amplifier

1230: first filter

1240: second filter

1310～1340: The third filter

1251, 1252: switch

1261, 1262: Antenna

TX1, TX2: Transmitter

RX1, RX2: Receiver

Detailed ways

FIG. 1 is a schematic circuit diagram of a filter according to an embodiment of the invention. As shown in FIG. 1 , the filter 100 has an input terminal IN and an output terminal OUT, and the filter 100 includes an energy storage element 110 , series resonant circuits 120 and 130 , and parallel resonant circuits 140 and 150 . Wherein, the energy storage element 110 is electrically connected between the input terminal IN and the output terminal OUT. Each of the series resonant circuits 120 and 130 includes a capacitor and an inductor connected in series. For example, the series resonant circuit 120 includes a capacitor C11 and an inductor L11 connected in series, and the series resonant circuit 130 includes a capacitor C12 and an inductor L12 connected in series.

The parallel resonant circuits 140 and 150 each include a capacitor and an inductor connected in parallel. For example, the parallel resonant circuit 140 includes a capacitor C21 and an inductor L21 connected in parallel, and the parallel resonant circuit 150 includes a capacitor C22 and an inductor L22 connected in parallel. Furthermore, the series resonant circuit 120 and the parallel resonant circuit 140 are stacked between the first end of the energy storage element 110 and the ground end. The series resonant circuit 130 and the parallel resonant circuit 150 are stacked between the second terminal of the energy storage element 110 and the ground terminal. In this way, the filter 100 with a pass band and a stop band can be formed.

For example, in the embodiment of FIG. 1 , the energy storage element 110 may be, for example, an inductor L3. In addition, the first terminal of the inductor L3 is electrically connected to the input terminal IN and the capacitor C11 in the series resonant circuit 120 , and the second terminal of the inductor L3 is electrically connected to the output terminal OUT and the capacitor C12 in the series resonant circuit 130 . The inductor L11 in the series resonant circuit 120 is electrically connected to the capacitor C21 and the inductor L21 in the parallel resonant circuit 140 . The inductor L12 in the series resonant circuit 130 is electrically connected to the capacitor C22 and the inductor L22 in the parallel resonant circuit 150 . Accordingly, the energy storage element 110, the series resonant circuits 120 and 130, and the resonant circuits 140 and 150 can form a 5th-order filter with a low-pass type.

FIG. 2 is a schematic diagram illustrating the frequency response of the filter in FIG. 1 . As shown in FIG. 2 , the characteristic curve of the filter 100 includes a passband 210 and a stopband 220 . Wherein, the frequency of the passband 210 covers 5.17˜5.25 GHz (ie, the UNII-1 frequency band), and the frequency of the stop band 220 covers 5.735˜5.815 GHz (ie, the UNII-3 frequency band). In addition, the insertion loss of the filter 100 in the passband 210 is about 0.7 dB, and the attenuation of the filter 100 in the stopband 220 can reach at least -39 dB. In other words, the passband 210 of the filter 100 is very flat, and the filter 100 attenuates quickly in the transition band.

Therefore, compared with the existing filters, the filter 100 can have good performance without expanding the order of the filter 100, thereby helping to reduce the production cost of the wireless communication device and helping the wireless communication device miniaturization. Besides, the characteristic curve of the filter 100 includes two turning points P21 and P22. Therefore, in addition to attenuating the signal in the stopband 220, the filter 100 can further attenuate the signal in the filtering frequency band 230 (ie, 2.412˜2.484 GHz). For example, the attenuation of the filter 100 within the filter band 230 can be as low as -27 dB.

It is worth mentioning that, in the embodiment of FIG. 1 , the capacitance of the capacitor C11 is equal to the capacitance of the capacitor C12 , and the capacitance of the capacitor C21 is equal to the capacitance of the capacitor C22 . In addition, the capacitance of the capacitor C11 is greater than the capacitance of the capacitor C21. The inductance value of the inductor L11 is equal to the inductance value of the inductor L12 , and the inductance value of the inductor L21 is equal to the inductance value of the inductor L22 . In addition, the inductance value of the inductor L3 is greater than the inductance value of the inductor L11 , and the inductance value of the inductor L21 is greater than the inductance value of the inductor L3 . In addition, those skilled in the art can also adjust the capacitance values of the above-mentioned capacitors and the inductance values of the inductors according to design requirements.

Although FIG. 1 lists types of filters, it is not intended to limit the present invention. Those skilled in the art can adjust the components of the energy storage element 110, and the connection sequence of the capacitors and inductors in the series resonant circuits 120 and 130, so as to form an energy storage element, two series resonant circuits and two parallel resonant circuits. High-pass type filter.

For example, FIG. 3 is a schematic circuit diagram of a filter according to another embodiment of the present invention. In the embodiment of FIG. 3 , the energy storage element 310 can be, for example, a capacitor C3. In addition, the first terminal of the capacitor C3 is electrically connected to the input terminal IN and the inductor L31 of the series resonant circuit 320 , and the second terminal of the capacitor C3 is electrically connected to the output terminal OUT and the inductor L32 of the series resonant circuit 330 . The capacitor C31 in the series resonant circuit 320 is electrically connected to the capacitor C21 and the inductor L21 in the parallel resonant circuit 140 , and the capacitor C32 in the series resonant circuit 330 is electrically connected to the capacitor C22 and the inductor L22 in the parallel resonant circuit 150 . Wherein, the capacitance values of the capacitors C31, C32, C21 and C22 are the same, and the capacitance value of the capacitor C3 is smaller than the capacitance value of the capacitor C31. The inductance value of the inductor L31 is equal to the inductance value of the inductor L32, and the inductance value of the inductor L31 is smaller than the inductance value of the inductor L21. Accordingly, the energy storage element 310, the series resonant circuits 320 and 330, and the resonant circuits 140 and 150 can form a 5th-order filter with a high-pass type.

FIG. 4 is a schematic diagram illustrating the frequency response of the filter in FIG. 3 . As shown in FIG. 4 , the characteristic curve of the filter 300 includes a passband 410 and a stopband 420 . Wherein, the frequency of the passband 410 covers 5.735˜5.815 GHz (ie, the UNII-3 frequency band), and the frequency of the stop band 420 covers 5.17˜5.25 GHz (ie, the UNII-1 frequency band). In addition, the insertion loss of the filter 300 in the passband 410 is about 0.9 dB, and the attenuation of the filter 300 in the stopband 420 can reach at least -41 dB. Furthermore, the characteristic curve of the filter 300 includes two turning points P41 and P42. Therefore, in addition to attenuating the signal in the stopband 420, the filter 300 can further attenuate the signal in the filtering frequency band 430 (ie, 2.412˜2.484 GHz). For example, the attenuation of the filter 300 within the filter band 430 can be as low as -47 dB.

It should be noted that the capacitors C11 , C12 , C21 , C22 , C3 , C31 , C32 and the inductors L11 , L12 , L21 , L22 , L3 , L31 , L32 in the above-mentioned filters 100 and 300 can be chip-type components respectively. That is, the capacitors C11, C12, C21, C22, C3, C31, and C32 in the filters 100 and 300 can be formed by a chip capacitor respectively, and the inductors L11, L12, L21 , L22 , L3 , L31 , and L32 can be formed by a chip inductor respectively. In other words, the filters 100 and 300 can be combined by chip inductors and chip capacitors, so the size and price of the filters 100 and 300 can be effectively reduced, thereby contributing to the miniaturization of wireless communication devices and reducing the production cost of wireless communication devices .

For example, FIG. 5 is a schematic layout diagram of a filter according to an embodiment of the present invention. As shown in FIG. 5 , chip-type components 511 - 519 are disposed on a surface 521 of a substrate 520 . In addition, the chip-type components 511 - 519 can be a chip inductor or a chip capacitor respectively. For example, the chip-type components 511 and 514-517 can be a chip inductor respectively, and the chip-type components 512, 513, 518 and 519 can be respectively a chip capacitor, so that the chip-type components 511-519 can be formed as shown in FIG. The filter shown has a low-pass pattern. In addition, the conductive wires 530 and 540 are respectively used to form the input terminal and the output terminal of the filter, and the conductive surface 550 is used as the ground terminal of the filter.

The embodiments in FIG. 1 and FIG. 3 are used to illustrate the filters 100 and 300 of 5th order. However, in another embodiment, those skilled in the art can also extend the order of the filters 100 and 300 to 8, 11, 14, 17... orders according to design requirements. For example, FIG. 6 is a schematic circuit diagram of a filter according to another embodiment of the present invention. Compared with the embodiment in FIG. 1 , the filter 600 in FIG. 6 further includes an energy storage element 610 , a series resonant circuit 620 and a parallel resonant circuit 630 . Wherein, the first end of the energy storage element 610 is electrically connected to the energy storage element 110 , and the second end of the energy storage element 610 is electrically connected to the output terminal OUT. In addition, the energy storage element 610 can be, for example, an inductor L63.

Similar to the series resonant circuit 120 , the series resonant circuit 620 includes a capacitor C61 and an inductor L61 , and the capacitor C61 and the inductor L61 are sequentially connected in series between the second end of the inductor L63 and the parallel resonant circuit 630 . Similar to the parallel resonant circuit 140 , the parallel resonant circuit 630 includes an inductor L62 and a capacitor C62 connected in parallel between the inductor L61 and the ground. In addition, the series resonant circuit 620 and the parallel resonant circuit 630 are stacked between the second end of the energy storage element 610 and the ground end. In this way, the energy storage element 610 , the series resonant circuit 620 and the parallel resonant circuit 630 can expand the order of the filter 600 to 8th order. In other words, the filter 600 of FIG. 6 may be, for example, an 8th-order filter with a low-pass type. It is worth mentioning that, in another embodiment, the energy storage element 610 may also be electrically connected between the input terminal IN and the energy storage element 110 , for example. That is, in another embodiment, the first end of the energy storage element 610 is electrically connected to the energy storage element 110 , and the second end of the energy storage element 610 is electrically connected to the input terminal IN.

FIG. 7 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention. Compared with the embodiment in FIG. 3 , the filter 700 in FIG. 7 further includes an energy storage element 710 , a series resonant circuit 720 and a parallel resonant circuit 730 . Wherein, the energy storage element 710 is disposed between the energy storage element 310 and the output terminal OUT, and the energy storage element 710 can be, for example, a capacitor C73. The series resonant circuit 720 has the same circuit structure as the series resonant circuit 320 , and the parallel resonant circuit 730 has the same circuit structure as the parallel resonant circuit 140 . For example, the series resonant circuit 720 includes an inductor L71 and a capacitor C71 connected in series, and the parallel resonant circuit 730 includes an inductor L72 and a capacitor C72 connected in parallel. In addition, the series resonant circuit 720 and the parallel resonant circuit 730 are stacked between the second end of the energy storage element 710 and the ground end. Accordingly, the filter 700 of FIG. 7 may be, for example, an 8th-order filter with a high-pass type. In another embodiment, the energy storage element 710 may also be electrically connected between the input terminal IN and the energy storage element 310 , for example.

It is worth mentioning that those skilled in the art can also add a series resonant circuit to both ends of the filter according to the design requirements, so as to add another filtering frequency band to filter out the second-order harmonic distortion (harmonic distortion) . For example, FIG. 8 is a schematic circuit diagram of a filter according to another embodiment of the present invention. Compared with the embodiment in FIG. 1 , the filter 800 further includes series resonant circuits 810 and 820 . Wherein, the series resonant circuit 810 is electrically connected to the input terminal IN, and the series resonant circuit 820 is electrically connected to the output terminal OUT.

The series resonant circuits 810 and 820 each include a capacitor and an inductor connected in series, and the series sequence of the capacitor and the inductor can be reversed arbitrarily. For example, the series resonant circuit 810 includes a capacitor C81 and an inductor L81, and the series resonant circuit 820 includes a capacitor C82 and an inductor L82. The capacitor C81 and the inductor L81 are sequentially connected in series between the input terminal IN and the ground terminal, and the sequence of the capacitor C81 and the inductor L81 can be reversed. Similarly, the capacitor C82 and the inductor L82 are sequentially connected in series between the output terminal OUT and the ground terminal, and the sequence of the capacitor C82 and the inductor L82 can be reversed. Accordingly, the filter 800 can increase another filtering frequency band through the series resonant circuits 810 and 820 .

For example, FIG. 9 is a schematic diagram illustrating the frequency response of the filter in FIG. 8 . As shown in FIG. 9 , the filter 800 can generate a passband 910, a stopband 920, and a filter frequency band 930 through the energy storage element 110, the series resonant circuits 120 and 130, and the parallel resonant circuits 140 and 150, and the filter 800 can further be connected in series The resonant circuits 810 and 820 generate another filter band 940, thereby filtering out the second order harmonic distortion. Wherein, the center frequency f1 of the filtering frequency band 940 can be expressed as

L1 is the inductance of the inductor L81 and the inductor L82 , and C1 is the capacitance of the capacitor C81 and the capacitor C82 . In addition, the passband 910 of the filter 800 may, for example, cover 5.17˜5.25 GHz (ie, the UNII-1 frequency band), and the frequency of the second harmonic will be equal to (5.17+5.25)=10.42 GHz. In order to suppress the second-order harmonic distortion, the center frequency f1 of the filter frequency band 940 can be set to 10.42GHz, and the inductance values of the inductors L81 and L82 and the capacitance values of the capacitors C81 and C82 can be calculated by the above formula (1) .

Similarly, FIG. 10 is a schematic circuit diagram of a filter according to yet another embodiment of the present invention, and FIG. 11 is a schematic diagram illustrating the frequency response of the filter in FIG. 10 . Compared with the embodiment in FIG. 3 , the filter 1000 further includes series resonant circuits 1010 and 1020 . Wherein, the series resonant circuit 1010 is electrically connected to the input terminal IN, and the series resonant circuit 1020 is electrically connected to the output terminal OUT. The series resonant circuit 1010 includes an inductor L101 and a capacitor C101 connected in series, and the series sequence of the inductor L101 and the capacitor C101 can be reversed. Similarly, the series resonant circuit 1020 includes a capacitor C102 and an inductor L102 connected in series, and the serial order of the capacitor C102 and the inductor L102 can be reversed. Accordingly, the filter 1000 can increase another filtering frequency band through the series resonant circuits 1010 and 1020 .

For example, as shown in FIG. 11 , the filter 1000 can generate a passband 1110, a stopband 1120, and a filter frequency band 1130 through the energy storage element 310, the series resonant circuits 320 and 330, and the parallel resonant circuits 140 and 150, and the filter 1000 Another filter frequency band 1140 can also be generated by the series resonant circuits 1010 and 1020 to filter out the second order harmonic distortion. For example, the center frequency f2 of the filter frequency band 1140 can be expressed by formula (2) as

L2 is the inductance of the inductor L101 and the inductor L102 , and C2 is the capacitance of the capacitor C101 and the capacitor C102 . In addition, the passband 1110 of the filter 1000 may, for example, cover 5.735˜5.815 GHz (ie, the UNII-3 frequency band), and the frequency of the second harmonic will be equal to (5.735+5.815)=11.55 GHz. In order to suppress the second-order harmonic distortion, the center frequency of the filter frequency band 1140 can be set to 11.55 GHz, and the inductance values of the inductors L101 and L102 and the capacitance values of the capacitors C101 and C102 can be calculated through the above formula (2).

Compared with existing filters, the filters 100 , 300 , 600 , 700 , 800 , and 1000 listed in the above embodiments have better frequency responses and steeper attenuation slopes. Therefore, the filters listed in the above-mentioned embodiments have steep filtering curves or high isolation characteristics, and can be applied in wireless communication devices with parallel dual-radio operation, so as to solve the problem of wireless communication devices operating between two adjacent frequency bands. mutual interference between them.

For example, FIG. 12 is a block diagram of a wireless communication device according to an embodiment of the present invention. As shown in FIG. 12 , the wireless communication device 1200 includes transceivers 1211 and 1212 , power amplifiers 1221 and 1222 , a first filter 1230 , a second filter 1240 , switches 1251 and 1252 , and antennas 1261 and 1262 . Wherein, the transceivers 1211 and 1212 each include at least one signal terminal. For example, the signal end of the transceiver 1211 includes a transmitting end TX1 and a receiving end RX1, and the transceiver 1211 can be electrically connected to the antenna 1261 through the transmitting end TX1 or the receiving end RX1. Similarly, the signal end of the transceiver 1212 includes a transmitting end TX2 and a receiving end RX2, and the transceiver 1212 can be electrically connected to the antenna 1262 through the transmitting end TX2 or the receiving end RX2. In another embodiment, the transceiver 1211 and the transceiver 1212 may each include a plurality of transmitting terminals and a plurality of receiving terminals, and each may be equipped with a plurality of switches to connect the multiple transmitting terminals and the multiple receiving terminals to multiple The antenna further causes the transceiver 1211 and the transceiver 1212 to have a multiple-input multiple-output (MIMO) transmission mechanism, thereby increasing the data transmission rate.

For the transceiver 1211, the switch 1251 has a first terminal to a third terminal. The first end of the switch 1251 is electrically connected to the antenna 1261 , and the second end of the switch 1251 is electrically connected to the receiving end RX1 . The power amplifier 1221 and the first filter 1230 are connected in series between the transmitting end TX1 and the third end of the switch 1251 . The transceiver 1211 can use a control signal to control the switch 1251 so that the first terminal of the switch 1251 is turned on to the second terminal or the third terminal of the switch 1251 . In other words, the switch 1251 can connect the antenna 1261 to the first filter 1230 or the receiving end RX1 , so that the wireless communication device 1200 can transmit or receive radio frequency signals through the antenna 1261 . For example, when the switch 1251 connects the antenna 1261 to the first filter 1230, the power amplifier 1221 can amplify the signal from the transmitting end TX1 and generate an output signal accordingly. The first filter 1230 filters the output signal of the power amplifier 1221 , so that the wireless communication device 1200 can transmit a radio frequency signal in the passband of the first filter 1230 through the antenna 1261 .

As far as the transceiver 1212 is concerned, the switch 1252 has a first terminal to a third terminal. The first end of the switch 1252 is electrically connected to the antenna 1262 , and the second end of the switch 1252 is electrically connected to the receiving end RX2 . The power amplifier 1222 and the second filter 1240 are connected in series between the transmitting end TX2 and the third end of the switch 1252 . The transceiver 1212 can use a control signal to control the switch 1252 so that the first terminal of the switch 1252 is turned on to the second terminal or the third terminal of the switch 1252 . In other words, the switch 1252 can connect the antenna 1262 to the second filter 1240 or the receiving end RX2 , so that the wireless communication device 1200 can transmit or receive radio frequency signals through the antenna 1262 . For example, when the switch 1252 connects the antenna 1262 to the second filter 1240, the power amplifier 1222 can amplify the signal from the transmitting end TX2 and generate an output signal accordingly. The second filter 1240 filters the output signal of the power amplifier 1222 , so that the wireless communication device 1200 can transmit the radio frequency signal in the passband of the second filter 1240 through the antenna 1262 .

It is worth mentioning that the passband of the first filter 1230 is the same as the stopband of the second filter 1240 , and the stopband of the first filter 1230 is the same as the passband of the second filter 1240 . For example, the first filter 1230 may be, for example, the low-pass filter 100 of FIG. 1 , and the second filter 1240 may be, for example, the high-pass filter 300 of FIG. 3 . At this time, as shown in FIG. 2 and FIG. 4 , the first filter 1230 includes a passband 210 (that is, the UNII-1 frequency band), a stopband 220 (that is, the UNII-3 frequency band) and a filtering frequency band 230 (that is, the UNII-3 frequency band). , 2.412～2.484GHz), and the second filter 1240 includes passband 410 (that is, UNII-3 frequency band), stopband 420 (that is, UNII-1 frequency band) and filter frequency band 430 (that is, 2.412～2.484 GHz).

In this way, the wireless communication device 1200 can simultaneously transmit radio frequency signals in the two passbands of the first filter 1230 and the second filter 1240 (that is, the UNII-1 frequency band and the UNII-3 frequency band), and can avoid Mutual interference between adjacent two passbands (ie, UNII-1 frequency band and UNII-3 frequency band) causes the wireless communication device 1200 to perform parallel dual-radio operation. In addition, the wireless communication device 1200 can additionally filter out signals within the filtering frequency band through the filtering frequency bands of the first filter 1230 and the second filter 1240 (ie, 2.412˜2.484 GHz), thereby helping to improve the performance of the wireless communication device. 1200 communication quality or reduce the interference of other communication devices used in the 2.412-2.484GHz frequency band. Furthermore, since the first filter 1230 and the second filter 1240 have sufficient attenuation without increasing the order, and the first filter 1230 and the second filter 1240 can be formed by a combination of chip inductors and chip capacitors, the second The first filter 1230 and the second filter 1240 can effectively reduce the production cost of the wireless communication device 1200 and help miniaturization of the wireless communication device 1200 .

Although the embodiment in FIG. 12 lists the architecture of the wireless communication device 1200, it is not intended to limit the present invention. Those skilled in the art can set multiple filters on the transmitting path and the receiving path of the transceiver according to design requirements, so as to further improve the communication quality of the wireless communication device. For example, FIG. 13 is a block diagram of a wireless communication device according to another embodiment of the present invention.

Compared with the embodiment in FIG. 12 , the wireless communication device 1300 in FIG. 13 further includes third filters 1310 - 1340 . Wherein, the circuit structure of the third filter 1310 and 1320 is the same as that of the first filter 1230 . For example, the first filter 1230 and the third filters 1310 - 1320 may be, for example, the low-pass filters shown in FIG. 1 , FIG. 6 or FIG. 8 . In addition, the third filter 1310 is serially inserted between the transmitting terminal TX1 and the power amplifier 1221 , and the third filter 1320 is serially inserted between the receiving terminal RX1 and the second terminal of the switch 1251 . The circuit structure of the third filter 1330 and 1340 is the same as that of the second filter 1240 . For example, the second filter 1240 and the third filters 1330 - 1340 may be, for example, the high-pass filters shown in FIG. 3 , FIG. 7 or FIG. 10 . In addition, the third filter 1330 is serially inserted between the transmitting terminal TX2 and the power amplifier 1222 , and the third filter 1340 is serially inserted between the receiving terminal RX2 and the second terminal of the switch 1252 . Thereby, the wireless communication device 1300 can simultaneously receive radio frequency signals in the two passbands of the third filter 1320 and the third filter 1340 (ie, the UNII-1 frequency band and the UNII-3 frequency band). In addition, the wireless communication device 1300 can also attenuate more wireless interference (eg, same-channel interference, adjacent-channel interference) through the third filters 1310 - 1340 , thereby helping to improve the communication quality of the wireless communication device 1300 . It is worth mentioning that those skilled in the art can choose one of the first filter 1230 and the third filter 1310 to be arranged on the transmission path of the transceiver 1211 according to design requirements, and can place the second filter 1310 according to design requirements. Either one of 1240 and the third filter 1330 is set on the transmission path of the transceiver 1212 .

To sum up, in the present invention, a series resonant circuit and a parallel resonant circuit are respectively stacked at both ends of the energy storage element to form a filter. The filter has sufficient attenuation without increasing the order, and can be formed by combining chip inductors and chip capacitors. Therefore, the filter can effectively reduce the production cost of the wireless communication device and contribute to the miniaturization of the wireless communication device.

Although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention, and any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, so the protection of the present invention The scope is defined by the claims of the present invention.

Claims (20)

1. a kind of filter has an input terminal and an output end, and includes：

One first energy-storage travelling wave tube, is electrically connected between the input terminal and the output end；

One first and one second series resonant circuit includes respectively one first capacitance and one first inductance being serially connected；And

One first and one second antiresonant circuit, respectively include one second capacitance and one second inductance parallel with one another,

Wherein, first series resonant circuit and first antiresonant circuit be connected on the first end of first energy-storage travelling wave tube with Between one ground terminal, and second series resonant circuit and second antiresonant circuit are connected on the of first energy-storage travelling wave tube Between two ends and the ground terminal, to form the filter with a passband and a stopband.

2. filter as described in claim 1, wherein first energy-storage travelling wave tube are a third inductance, the first of the third inductance End is electrically connected the input terminal and first capacitance in first series resonant circuit, and the second end of the third inductance is electrical Connect the output end and first capacitance in second series resonant circuit.

3. filter as claimed in claim 2, first inductance wherein in first series resonant circuit is electrically connected should Second capacitance in first antiresonant circuit and second inductance, and first inductance in second series resonant circuit Second capacitance and second inductance being electrically connected in second antiresonant circuit.

4. filter as claimed in claim 3, wherein the third inductance, this first with second series resonant circuit in this A little first capacitances and these first inductance and this first in second antiresonant circuit these second capacitances and these Second inductance is all chip type component.

5. filter as described in claim 1, wherein first energy-storage travelling wave tube are a third capacitance, the first of the third capacitance End is electrically connected the input terminal and first inductance in first series resonant circuit, and the second end of the third capacitance is electrical Connect the output end and first inductance in second series resonant circuit.

6. filter as claimed in claim 5, first capacitance wherein in first series resonant circuit is electrically connected should Second capacitance in first antiresonant circuit and second inductance, and first capacitance in second series resonant circuit Second capacitance and second inductance being electrically connected in second antiresonant circuit.

7. filter as claimed in claim 6, wherein the third capacitance, this first with second series resonant circuit in this A little first capacitances and these first inductance and this first in second antiresonant circuit these second capacitances and these Second inductance is all chip type component.

8. filter as described in claim 1, further includes：

One second energy-storage travelling wave tube, first end are electrically connected first energy-storage travelling wave tube, and the second end of second energy-storage travelling wave tube is electrical Connect the input terminal or the output end；

One third series resonant circuit；And

One third antiresonant circuit, wherein the third series resonant circuit and the third antiresonant circuit be connected on this second Between the second end of energy-storage travelling wave tube and the ground terminal, and to increase the exponent number of the filter.

9. filter as described in claim 1, further includes：

One third series resonant circuit, is electrically connected the input terminal；And

One the 4th series resonant circuit, is electrically connected the output end, wherein the filter by the third series resonant circuit with 4th series resonant circuit filters out the signal in a filtered band.

10. filter as claimed in claim 9, wherein the third series resonant circuit with the 4th series resonant circuit respectively Including an inductance and a capacitance.

11. a kind of wireless communication device, including：

One first transceiver is electrically connected a first antenna by least one first signal end；

One second transceiver is electrically connected one second antenna by an at least second signal end；

One first filter, including one first passband and one first stopband, and be arranged at least one first signal end and this Between one antenna；And

One second filter, including one second passband and one second stopband, and be arranged an at least second signal end and this Between two antennas, wherein first passband is identical as second stopband, and first stopband is identical as second passband, and this One filter respectively has an input terminal and an output end with the second filter, and includes respectively：

One first energy-storage travelling wave tube, is electrically connected between the input terminal and the output end；

One first and one second series resonant circuit includes respectively one first capacitance and one first inductance being serially connected；And

One first and one second antiresonant circuit, respectively including one second capacitance and one second inductance parallel with one another, wherein First series resonant circuit is connected on the first end and a ground terminal of first energy-storage travelling wave tube with first antiresonant circuit Between, the second end which is connected on first energy-storage travelling wave tube with second antiresonant circuit connects with this Between ground terminal.

12. wireless communication device as claimed in claim 11, wherein at least one first signal end include one first transmitting terminal With one first receiving terminal, and the wireless communication device further includes：

There is one first switch a first end to a third end, the first end of the first switch to be electrically connected the first antenna, should The second end of first switch is electrically connected first receiving terminal；And

One first power amplifier, with the first filter be connected on first transmitting terminal and the first switch third end it Between, wherein the first end of the first switch is conducted to second end or the third end of the first switch by the first transceiver.

13. wireless communication device as claimed in claim 12, further includes：

One third filter, it is identical as the circuit structure of the first filter, and be inserted in first receiving terminal and first opened with this Between the second end of pass.

14. wireless communication device as claimed in claim 12, wherein an at least second signal end include one second transmitting terminal With one second receiving terminal, and the wireless communication device further includes：

There is one second switch a first end to a third end, the first end of the second switch to be electrically connected second antenna, should The second end of second switch is electrically connected second receiving terminal；And

One second power amplifier, with the second filter be connected on second transmitting terminal and the second switch third end it Between, wherein the first end of the second switch is conducted to second end or the third end of the second switch by the second transceiver.

15. wireless communication device as claimed in claim 14, further includes：

One third filter, it is identical as the circuit structure of the second filter, and be inserted in second receiving terminal and second opened with this Between the second end of pass.

16. wireless communication device as claimed in claim 11, first energy-storage travelling wave tube wherein in the first filter is one Third inductance, the first end of the third inductance be electrically connected the input terminal of the first filter and the first filter this First capacitance in one series resonant circuit, and the second end of the third inductance is electrically connected the output of the first filter End and first capacitance in second series resonant circuit of the first filter.

17. wireless communication device as claimed in claim 16, first energy-storage travelling wave tube wherein in the second filter is one Third capacitance, the first end of the third capacitance be electrically connected the input terminal of the second filter and the second filter this First inductance in one series resonant circuit, and the second end of the third capacitance is electrically connected the output of the second filter End and first inductance in second series resonant circuit of the second filter.

18. wireless communication device as claimed in claim 17, wherein the third inductance, the third capacitance, the first filter With in the second filter these first capacitances and these first inductance and the first filter in the second filter These second capacitances and these second inductance be all chip type component.

19. wireless communication device as claimed in claim 11, the wherein first filter are respectively also wrapped with the second filter It includes：

One second energy-storage travelling wave tube, first end are electrically connected first energy-storage travelling wave tube, and the second end of second energy-storage travelling wave tube is electrical Connect the output end；

One third series resonant circuit is identical as the circuit structure of first series resonant circuit；And

One third antiresonant circuit, wherein third series resonance identical as the circuit structure of first antiresonant circuit Circuit and the third antiresonant circuit are connected between the second end of second energy-storage travelling wave tube and the ground terminal.

20. wireless communication device as claimed in claim 11, the wherein first filter are respectively also wrapped with the second filter It includes：

One third series resonant circuit, is electrically connected the input terminal；And

One the 4th series resonant circuit, is electrically connected the output end, and wherein the third series resonant circuit is connected humorous with the 4th Circuit shake to filter out the signal in a filtered band.