CN217721148U - Bulk acoustic wave duplexer - Google Patents
Bulk acoustic wave duplexer Download PDFInfo
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- CN217721148U CN217721148U CN202221320885.XU CN202221320885U CN217721148U CN 217721148 U CN217721148 U CN 217721148U CN 202221320885 U CN202221320885 U CN 202221320885U CN 217721148 U CN217721148 U CN 217721148U
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Abstract
The utility model discloses a bulk acoustic wave duplexer, including Tx wave filter, rx wave filter and move the looks ware, the one end of Rx wave filter connects gradually and moves looks ware and antenna end, and the other end meets with low noise amplifier, and the one end of Tx wave filter and antenna end and move the looks ware and be connected, and the other end meets with power amplifier, tx wave filter and Rx wave filter are multistage wave filter, including a plurality of string arm syntonizers and a plurality of parallel arm syntonizers in the Tx wave filter, wherein part parallel arm syntonizer still establishes ties has an inductance, including a plurality of string arm syntonizers and a plurality of parallel arm syntonizers in the Rx wave filter, wherein part parallel arm syntonizer still establishes ties has an inductance. The utility model discloses a phase shifter is moved in the setting, promotes the input impedance of Rx wave filter at the Tx frequency channel, has solved the impedance matching problem between Tx wave filter and the Rx wave filter and in order to promote the port return loss to through introducing the inductance in the circuit of arm syntonizer, promote the outband suppression.
Description
Technical Field
The utility model relates to an electronic communication device technical field especially relates to a bulk acoustic wave duplexer.
Background
The duplexer is a main accessory of the different-frequency duplex radio station and the relay station, has the functions of isolating the transmitted signal from the received signal and ensuring the normal operation of both the receiving and the transmitting simultaneously, and consists of two groups of band-pass filters with different frequencies to avoid the transmission of the transmitted signal of the local machine to the receiver.
The operation principle of the BAW duplexer is the same as that of a general frequency division duplexer, that is, the same antenna can transmit and receive signals in different frequency bands at the same time, except that the receiving filter (Rx filter) and the transmitting filter (Tx filter) are BAW filters. The passband frequency band of the Rx filter is typically higher than the passband frequency band of the Tx filter.
The existing duplexer is composed of a transmitting filter and a receiving filter, and the transmitting filter and the receiving filter are both realized by the existing filters, but the technology has the problems of out-of-band rejection and low port return loss.
SUMMERY OF THE UTILITY MODEL
To the lower problem of prior art outband suppression and port return loss, the utility model provides a bulk acoustic wave duplexer to the impedance matching problem of Tx and Rx wave filter in the BAW duplexer, through setting up the looks ware that moves, promotes the input impedance of Rx wave filter at the Tx frequency channel, has solved the impedance matching problem between Tx wave filter and the Rx wave filter in order to promote the port return loss to through introducing the inductance in the circuit of arm syntonizer, promote the outband suppression.
The technical proposal of the utility model is as follows.
A bulk acoustic wave duplexer comprises a Tx filter, an Rx filter and a phase shifter, wherein one end of the Rx filter is connected with an antenna end and the phase shifter, the other end of the Rx filter is connected with a low noise amplifier, one end of the Tx filter is sequentially connected with the phase shifter and the antenna end, the other end of the Tx filter is connected with a power amplifier, the Tx filter and the Rx filter are both multi-order filters, the Tx filter comprises a plurality of serial-arm resonators and a plurality of parallel-arm resonators, part of the parallel-arm resonators are connected with an inductor in series, the Rx filter comprises a plurality of serial-arm resonators and a plurality of parallel-arm resonators, and part of the parallel-arm resonators are connected with an inductor in series.
One end of one parallel-arm resonator is connected between every two series-arm resonators starting from the first series-arm resonator Y1, and the other end of each resonator in the parallel-arm resonators is connected to the ground or an inductor.
The input impedance of the Tx filter in the BAW duplexer is high in the Rx band, and the input impedance of the Rx filter in the Tx band is low, so that a phase shifter needs to be connected before the antenna end and the Rx filter to raise the input impedance of the Rx filter in the Tx band, so as to prevent the Rx filter from loading the Tx filter and degrading the performance of the Tx filter.
Preferably, the passband of the Rx filter is 1745-1785MHz, and the passband of the Tx filter is 1805-1845MHz. In this specific frequency channel, the problem of outband suppression and port return loss is comparatively outstanding, and the circuit structure of this application can exert better effect at this frequency channel.
Preferably, the phase shifter includes an inductor L1, a capacitor C1 and a capacitor C2, two ends of the inductor L1 are respectively connected to a Tx filter and an Rx filter, and the capacitor C1 and the capacitor C2 are connected in parallel to two ends of the inductor L1. Generally, the input impedance of an Rx filter in a BAW duplexer is smaller in a band pass of a Tx filter, so that the performance of the Tx filter in the passband is deteriorated, the performance of the Rx filter in the passband is deteriorated, the 90-degree phase shifter can improve the input impedance of the Rx filter in the passband of the Tx filter, the impedance matching problem between the Tx filter and the Rx filter is solved, and the monolithic integration of the BAW duplexer is facilitated by adopting an LC pi-type circuit as the 90-degree phase shifter.
Preferably, the piezoelectric layer of the resonator is made of an aluminum nitride material, and the acoustic layer is made of a molybdenum material.
Preferably, the Tx filter is a fifth-order filter, the top electrodes of the five series-arm resonators have the same thickness, the top electrodes of the five parallel-arm resonators have the same thickness, and the first parallel-arm resonator Y2 and the fourth parallel-arm resonator Y8 are further connected in series with an inductor.
Preferably, in the Tx filter, the top electrodes of the five serial-arm resonators have a thickness of 1.56243 x 10-7m; the top electrodes of the five parallel-arm resonators had a thickness of 1.87234 x 10-7m。
Preferably, the Rx filter is a fifth-order filter, the top electrodes of the five series-arm resonators have the same thickness, and the top electrodes of the five parallel-arm resonators have the same thickness, wherein the sixth parallel-arm resonator Y12 and the ninth parallel-arm resonator Y18 are further connected in series with an inductor.
Preferably, in the Rx filter, the top electrodes of the five series-arm resonators have a thickness of 1.38241 × 10-7m; the top electrodes of the five parallel-arm resonators have a thickness of 1.65945 x 10-7m。
In order to better improve the return loss of the port, the thickness of each film layer of the resonator is optimized, and the return loss of the port can be larger than 15dB through the thickness.
Preferably, the Tx filter and the Rx filter further comprise several layers of narrow plates embedded with conductors and wires for connecting the internal circuit and the external circuit.
Preferably, a silicon cover plate is further included, the silicon cover plate being disposed on top of the Tx filter, the Rx filter and the phase shifter. To protect the underlying Tx filter, rx filter, etc.
The beneficial effects of the utility model include: the BAW duplexer is optimally designed, the input impedance of an Rx filter in a Tx frequency band is improved by arranging a phase shifter, the impedance matching problem between the Tx filter and the Rx filter is solved to improve the return loss of a port, the out-of-band rejection of the duplexer can be optimized by introducing an inductor, and therefore the high-performance duplexer in a specific frequency band is realized.
Drawings
Fig. 1 is a schematic circuit diagram of an embodiment of the present invention;
FIG. 2 is a block diagram of an embodiment of the present invention;
the figure includes: 1-Rx filter, 2-phase shifter, 3-Tx filter and 4-silicon cover plate.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Furthermore, in the following detailed description, numerous specific details are set forth in order to provide a better understanding of the invention. It will be understood by those skilled in the art that the present invention may be practiced without some of these specific details. In some instances, methods, means, elements and circuits that are well known to those skilled in the art have not been described in detail so as not to obscure the present invention.
In the description of the embodiments herein, "/" means "or" unless otherwise specified, for example, a/B may mean a or B; "and/or" herein is merely an association describing an associated object, and means that there may be three relationships, e.g., a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone.
In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present embodiment, "a plurality" means two or more unless otherwise specified.
Example (b):
a bulk acoustic wave duplexer comprises a Tx filter 3, an Rx filter 1, a phase shifter 2 and a silicon cover plate 4, wherein one end of the Rx filter is sequentially connected with the phase shifter and an antenna end, the other end of the Rx filter is connected with a low noise amplifier, one end of the Tx filter is connected with the antenna end and the phase shifter, the other end of the Tx filter is connected with a power amplifier, and the silicon cover plate is arranged at the tops of the Tx filter, the Rx filter and the phase shifter. The Tx and Rx filters also include several layers of narrow plates embedded with conductors and wires for connecting internal and external circuits.
The passband of the Rx filter of this embodiment is 1745-1785MHz, and the passband of the Tx filter is 1805-1845MHz. In this specific frequency channel, the problem of outband suppression and port return loss is comparatively outstanding, and the circuit structure of this application can exert better effect at this frequency channel.
As shown in fig. 1, the Tx filter and the Rx filter are both fifth-order filters, the Tx filter includes five series-arm resonators and five parallel-arm resonators, wherein the first parallel-arm resonator Y2 and the fourth parallel-arm resonator Y8 are also each connected in series with an inductor, and the Rx filter includes five series-arm resonators and five parallel-arm resonators, wherein the sixth parallel-arm resonator Y12 and the ninth parallel-arm resonator Y18 are also each connected in series with an inductor. Each two of the series-arm resonators is connected to one end of one parallel-arm resonator from the first series-arm resonator Y1, and the other end of each of the parallel-arm resonators is connected to a ground or an inductor.
The input impedance of the Tx filter in the BAW duplexer is high in the Rx band, and the input impedance of the Rx filter in the Tx band is low, so that a phase shifter needs to be connected before the antenna end and the Rx filter to raise the input impedance of the Rx filter in the Tx band, so as to prevent the Rx filter from loading the Tx filter and degrading the performance of the Tx filter.
The phase shifter of the embodiment includes an inductor L1, a capacitor C1 and a capacitor C2, where two ends of the inductor L1 are respectively connected to a Tx filter and an Rx filter, and the capacitor C1 and the capacitor C2 are connected in parallel to two ends of the inductor L1. Generally, the input impedance of an Rx filter in a BAW duplexer is smaller in the band pass of the Tx filter, which can cause the performance deterioration such as the insertion loss and the in-band fluctuation in the band pass of the Tx filter, the 90-degree phase shifter can improve the input impedance of the Rx filter in the band pass of the Tx filter, thereby solving the impedance matching problem between the Tx filter and the Rx filter, and the adoption of an LC pi-type circuit as the 90-degree phase shifter is more beneficial to the monolithic integration of the BAW duplexer.
In this embodiment, the piezoelectric layer of the resonator is made of aluminum nitride material, and the acoustic layer is made of molybdenum material. The choice of electrode material generally requires consideration of: low resistivity and low densityHigh acoustic speed, high acoustic impedance, etc. The electrode material used in the design is Mo, and the Mo has small sound wave error and large sound wave speed. The support layer is typically a layer of low stress material added between the bottom electrode and the substrate in order to increase the mechanical strength of the BAWR device. The supporting layer used in the design is made of SiO2。
As is known from the operating principle of BAW filters, the factor affecting the center frequency of the filter is the resonant frequency of the BAWR cell therein. From the BAWR working principle, the relation that the BAWR resonant frequency is in inverse proportion to the thickness of each film layer is obtained. Therefore, the design of the center frequency of the filter becomes the design of the thickness of each film layer of the BAWR unit.
In the Tx filter of the present embodiment, the top electrodes of the five series-arm resonators have the same thickness of 1.56243 × 10-7m; the top electrodes of the five parallel-arm resonators were uniform in thickness and were 1.87234 × 10-7And m is selected. In fig. 1, the top electrode areas of the five series-arm resonators of the Tx filter are sequentially: 1.51549*10-8m2、6.9189*10-9m2、8.43915*10-9m2、8.97523*10-9m2、8.97523*10-9m2. The top electrode areas of the five parallel-arm resonators of the Tx filter are sequentially: 6.35332*10-8m2、5.51226*10-8m2、5.06748*10-8m2、6.49345*10-9m2、6.49345*10-9m2。
In the Rx filter of this embodiment, the top electrodes of the five serial-arm resonators have the same thickness, which is 1.38241 × 10-7m; the top electrodes of the five parallel-arm resonators have the same thickness of 1.65945 × 10-7And m is selected. In fig. 1, the top electrode areas of the five series-arm resonators of the Rx filter are sequentially: 9.46214*10-9m2、7.93985*10-9m2、1.51004*10-8m2、1.29708*10-8m2、8.85891*10-8m2. The top electrode areas of the five parallel-arm resonators of the Rx filter are as follows in sequence: 8.99992*10-8m2、8.20362*10-8m2、8.40088*10-8m2、2.09977*10-8m2、3.32423*10-8m2。
By the above scheme, the final passband separation is about 65.3dB, and the port return loss is about 15.1dB.
Therefore, the embodiment raises the out-of-band rejection to above 60dB by introducing the inductance; the impedance matching problem between the Tx filter and the Rx filter is solved through the phase shifter, the parameters of the phase shifter are optimized, and the return loss of a port reaches more than 15dB. A high-performance BAW duplexer is realized in a specific frequency band.
Through the description of the above embodiments, those skilled in the art will understand that, for convenience and simplicity of description, only the division of the above functional modules is used as an example, and in practical applications, the above function distribution may be completed by different functional modules according to needs, that is, the internal structure of the device is divided into different functional modules to complete all or part of the above described functions.
Units described as separate parts may or may not be physically separate, and parts displayed as units may be one physical unit or a plurality of physical units, may be located in one place, or may be distributed to a plurality of different places. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. A bulk acoustic wave duplexer comprises a Tx filter, an Rx filter and a phase shifter, and is characterized in that one end of the Rx filter is sequentially connected with the phase shifter and an antenna end, the other end of the Rx filter is connected with a low noise amplifier, one end of the Tx filter is connected with the antenna end and the phase shifter, the other end of the Tx filter is connected with a power amplifier, the Tx filter and the Rx filter are both multi-order filters, the Tx filter comprises a plurality of serial-arm resonators and a plurality of parallel-arm resonators, wherein a part of the parallel-arm resonators are connected with an inductor in series, the Rx filter comprises a plurality of serial-arm resonators and a plurality of parallel-arm resonators, and a part of the parallel-arm resonators are connected with an inductor in series.
2. The bulk acoustic wave duplexer of claim 1, wherein the passband of the Rx filter is 1745-1785MHz, and the passband of the Tx filter is 1805-1845MHz.
3. The bulk acoustic wave duplexer according to claim 1, wherein the phase shifter comprises an inductor L1, a capacitor C1 and a capacitor C2, the two ends of the inductor L1 are respectively connected to the Tx filter and the Rx filter, and the capacitor C1 and the capacitor C2 are connected in parallel to the two ends of the inductor L1.
4. The bulk acoustic wave duplexer according to claim 1, wherein the piezoelectric layer of the resonator is made of an aluminum nitride material, and the acoustic layer is made of a molybdenum material.
5. The bulk acoustic wave duplexer according to claim 1 or 4, wherein the Tx filter is a fifth-order filter, the top electrodes of the five series-arm resonators are uniform in thickness, the top electrodes of the five parallel-arm resonators are uniform in thickness, and the first parallel-arm resonator Y2 and the fourth parallel-arm resonator Y8 are further connected in series with an inductor.
6. The bulk acoustic wave duplexer according to claim 5, wherein top electrodes of five series-arm resonators in the Tx filter have a thickness of 1.56243 x 10-7m; the top electrodes of the five parallel-arm resonators had a thickness of 1.87234 x 10- 7m。
7. The bulk acoustic wave duplexer according to claim 1 or 4, wherein the Rx filter is a fifth-order filter, the thicknesses of the top electrodes of the five series-arm resonators are the same, the thicknesses of the top electrodes of the five parallel-arm resonators are the same, and wherein the sixth parallel-arm resonator Y12 and the ninth parallel-arm resonator Y18 are each further connected in series with an inductor.
8. The bulk acoustic wave duplexer of claim 7, wherein top electrodes of five series-arm resonators in the Rx filter have a thickness of 1.38241 x 10-7m; the top electrodes of the five parallel-arm resonators have a thickness of 1.65945 × 10- 7m。
9. The bulk acoustic wave duplexer of claim 1, wherein the Tx and Rx filters further comprise a plurality of layers of strips embedded with conductors and wires for connecting internal and external circuits.
10. The bulk acoustic wave duplexer of claim 1, further comprising a silicon cover plate disposed on top of the Tx filter, the Rx filter and the phase shifter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN202221320885.XU CN217721148U (en) | 2022-05-27 | 2022-05-27 | Bulk acoustic wave duplexer |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221320885.XU CN217721148U (en) | 2022-05-27 | 2022-05-27 | Bulk acoustic wave duplexer |
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| CN217721148U true CN217721148U (en) | 2022-11-01 |
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