WO2022121818A1

WO2022121818A1 - Method, acoustic wave filter, multiplexer, and communication device for improving nonlinear performance

Info

Publication number: WO2022121818A1
Application number: PCT/CN2021/135624
Authority: WO
Inventors: 蔡华林; 庞慰
Original assignee: 诺思(天津)微系统有限责任公司
Priority date: 2020-12-07
Filing date: 2021-12-06
Publication date: 2022-06-16
Also published as: CN112468111A; CN112468111B

Abstract

A method, an acoustic wave filter, a multiplexer, and a communication device for improving nonlinear performance are disclosed. According to the method, the acoustic wave filter comprises a plurality of piezoelectric acoustic resonators and at least one set of parallel split resonator groups is included. The method comprises one or more of the following steps: differentiating the structure of each resonator wire in the parallel split resonator group, so that a non-linear component generated by each resonator is at least partially cancelled; changing the area and/or shape of each resonator in the parallel split resonator group, such that the non-linear component generated by each resonator is at least partially cancelled; and adding a conductor to the filter, so as to at least partially cancel the non-linear component generated by each resonator.

Description

Method and acoustic wave filter, multiplexer, communication device for improving nonlinear performance

technical field

The present invention relates to the technical field of filters, in particular to a method for improving the nonlinear performance of an acoustic wave filter, an acoustic wave filter, a multiplexer, and a communication device.

Background technique

The resonator in the filter will generate nonlinear components when the RF signal is input, and the nonlinear components will lead to the deterioration of the performance of the communication system. In the prior art, the non-linear splitting of the resonator causes the radio frequency signal to pass through the upper and lower electrodes of the two split resonators respectively, and the generated nonlinear components have the same amplitude and opposite phase, so the nonlinear components can be eliminated. Among them, parallel splitting is one of them. FIG. 1 is a schematic diagram of a resonator topology in a prior art filter. FIG. 2 is a schematic diagram of parallel splitting of resonators in a filter according to the prior art. As shown in FIG. 2 , as an example, the resonator 102 in FIG. 1 can be split into

parallel resonators

102 a and 102 b in FIG. 2 . Similarly, the resonator 113 in FIG. 1 can be split into two

parallel Resonators

113a, 113b.

In parallel splitting, due to the different electromagnetic environment around the two resonators split in parallel, the amplitude and phase of the nonlinear signals of the two channels will change, so that the amplitude and phase cannot be equal and the nonlinear signals can be completely eliminated.

SUMMARY OF THE INVENTION

In view of this, the present invention provides a method for improving the nonlinear performance of an acoustic wave filter, an acoustic wave filter, a multiplexer, and a communication device, which have the advantages of good performance, low cost, and wide application.

The present invention provides the following technical solutions:

A method for improving the nonlinear performance of an acoustic wave filter, the acoustic wave filter comprising a plurality of piezoelectric acoustic wave resonators and including at least one group of parallel split resonator groups, the method comprising one or more of the following: The structures of the connecting lines of the resonators in the parallel split resonator group are different, so that the nonlinear components generated by the resonators are at least partially cancelled; different areas and/or shapes of the resonators so that the nonlinear components generated by the resonators at least partially cancel; conductors are added to the filter to at least partially cancel the nonlinear components generated by the resonators ground offset.

Optionally, the structure of the resonator connection line includes one or more of the following: the position of the connection line, the length of the connection line, the width of the connection line, and the shape and area of the connection line.

Optionally, there are 2 resonators in the parallel split resonator group, wherein there is a first conductor near the first resonator; the step of adding conductors includes: resonating to a second resonator in the 2 resonators A second conductor is added near the resonator, and the electromagnetic environment formed by the second conductor and the second resonator is similar to the electromagnetic environment formed by the first conductor and the first resonator.

Optionally, the electromagnetic environment is one or more of the following: capacitance or mutual inductance between the connection line and the conductor near each resonator in the parallel split resonator group; the parallel split resonator group The capacitance or mutual inductance between each resonator in the sub-resonator group and the conductor near the resonator; the coupling capacitance or mutual inductance generated by the substrate or substrate of the acoustic wave filter.

Optionally, the connection manner of the second conductor is the same as the connection manner of the first conductor.

Optionally, the at least one parallel split resonator group is directly connected to the signal input end or output end of the acoustic wave filter.

Optionally, the step of adding conductors in the filter includes: adding conductors near one or more resonators in the parallel split resonator group, and the added conductors are used to make the parallel split resonators Each resonator in the sub-resonator group is in a similar electromagnetic environment.

Optionally, the added conductors are located at one or more of the following places: the layer where the upper electrode or the lower electrode of the resonator is located; the substrate or substrate of the filter; the inside or outside of the package structure of the filter.

Optionally, the number of resonators in the parallel split resonator group is an even number.

An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and including at least one group of parallel split resonator groups, in the acoustic wave filter: a structure in which at least 2 resonators in the parallel split resonator group are wired difference is used to at least partially cancel the nonlinear components generated by the at least two resonators.

An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and including at least one group of parallel split resonator groups, in the acoustic wave filter: in the parallel split resonator group, there are at least two resonators in area and/or different shapes are used to at least partially cancel the nonlinear components generated by the at least two resonators.

An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and including at least one group of parallel split resonator groups, in the acoustic wave filter, at least one group of parallel split resonator groups, the parallel split resonator group Each resonator in the resonator group is in a similar electromagnetic environment.

Optionally, the parallel split resonator group has added conductors, and the added conductors are located at one or more of the following places: the layer where the upper electrode or the lower electrode of the resonator is located; the substrate of the filter or substrate; inside or outside the package structure of the filter.

Optionally, the at least one parallel split resonator group is located at the signal output end of the ultrasonic filter.

Optionally, in the parallel split resonator group, the common end of each resonator is connected to the same side of other polygonal resonators.

A multiplexer includes the acoustic wave filter of the present invention.

A communication device comprising the acoustic wave filter of the present invention.

According to the technical solution of the present invention, by changing the wiring structure, the area and/or shape of the resonator, and the arrangement of conductors, etc., it helps to improve the nonlinear components generated by the parallel split resonators in the acoustic wave filter, and finally helps to improve the The nonlinear performance of the filter. This method is flexible to change, and has almost no impact on the size, cost and design of the filter; the impact on the chip layout and even the coupling of other structures such as substrates and substrates can also be eliminated.

Description of drawings

For purposes of illustration and not limitation, the present invention will now be described in accordance with preferred embodiments thereof, particularly with reference to the accompanying drawings, wherein:

1 is a schematic diagram of a filter topology according to the prior art;

2 is a schematic diagram of parallel splitting of resonators in the filter according to FIG. 1;

3 is a cross-sectional view of two resonators split in parallel;

4 is a cross-sectional view of two resonators split in parallel with a connection line nearby;

5 is a cross-sectional view of two resonators split in parallel with resonators nearby;

Figures 6a to 6f show schematic diagrams of changing the electromagnetic environment structure in different positions in the device;

Fig. 7a shows the device plan view of the parallel split resonator with improved nonlinear performance according to the first embodiment of the present invention;

Fig. 7b shows the device plan view of the parallel split resonator with improved nonlinear performance according to the second embodiment of the present invention;

Fig. 7c shows the device plan view of the parallel split resonator with improved nonlinear performance according to the third embodiment of the present invention;

FIG. 7d shows a device plan view of the parallel split resonator with improved nonlinear performance according to the fourth embodiment of the present invention.

Detailed ways

In the embodiment of the present invention, in the design of improving nonlinearity by splitting parallel resonators in the filter, when two parallel split resonators are in the surrounding electromagnetic environment of the two resonators (possibly because There are other resonators or traces or other structures), it is necessary to adjust the connection of one of the resonators, including adjusting the position, length, width, area and shape of the connection to ensure the nonlinear components flowing through the two resonators. The amplitude can be the same and the phase is reversed, so as to better eliminate the nonlinear components and improve the nonlinear performance of the filter, which will be explained in detail below.

Figure 3 shows a device plan view of a prior art parallel split resonator. As shown in FIG. 3 , there are two

parallel resonators

310A and 310B with connecting lines 320 and vias 330 nearby. The two resonators have the same area and the exact same shape. When the nonlinear components generated by the two channels of the two

resonators

310A and 310B have the same amplitude and opposite phases, the nonlinear components can be canceled to improve the nonlinear performance. The structure in the above figure is a parallel split structure, which can appear on the series branch of the filter or on the parallel branch. When appearing on the series branch, the A terminal and the B terminal are respectively connected to the middle of the adjacent left and right series resonators, or one end is connected to the input or output, and the other end is connected to the adjacent series resonator; when appearing in the parallel resonance On the branch, one end of the A terminal and the B terminal is connected to a node of the series branch (the node can be an input node or an output node, or an intermediate node in the series branch), and the other end is connected to the ground wire . Preferably, when the A terminal and/or the B terminal are connected to the resonator, and the resonator adopts a polygonal shape, the A terminal and/or the B terminal are the same side of the resonator at the corresponding connection. The other embodiments of the present invention also have the same preferred conditions.

In fact throughout the device, there are usually adjacent wires or resonators around the two parallel split resonators. As shown in FIG. 4 , there is a connection line 340 around the two

parallel split resonators

310A and 310B. Since the inductive coupling values generated by the connection line 340 and the two

resonators

310A and 310B are not equal, the two resonators 310A are and the nonlinear components generated on 310B are not equal, so the nonlinear components cannot be completely canceled. As shown in FIG. 5, there are other resonators 350 around the two

parallel split resonators

310A and 310B. Since the inductive coupling values generated by the resonator 350 and the two

resonators

310A and 310B are not equal, the two The nonlinear components generated on the

resonators

310A and 310B are not equal, so it is difficult to completely cancel the nonlinear components.

The wiring 340 or other resonators 350 in FIGS. 4 and 5 are essentially structures that change the electromagnetic environment. The electromagnetic environment is mainly formed by the electromagnetic interaction between conductors, such as: capacitance or mutual inductance between the above-mentioned wiring and conductors near the resonator; The capacitance or mutual inductance between the capacitive effect or mutual inductance effect); the coupling capacitance or mutual inductance generated by the substrate or substrate of the acoustic wave filter. The structure that modifies the electromagnetic environment can be widely present in different parts of the device. In FIGS. 6a to 6f, 610 denotes a substrate, 620 denotes a package wafer, 630 denotes a resonator wafer, and 601 denotes a structure for changing the electromagnetic environment. The structure 601 for changing the electromagnetic environment of the resonator wafer 630 produces unequal electromagnetic effects on the two

resonators

310A and 310B on the resonator wafer 630, resulting in unequal nonlinear components generated on the two

resonators

310A and 310B , so the nonlinear components cannot be completely canceled. As shown, the electromagnetic environment altering structure 601 may be located inside the package wafer 620 as shown in FIG. 6a, on the surface of the package wafer 620 as shown in FIG. 6b, or on the resonator wafer as shown in FIG. 6c 630, either inside the substrate 610 as shown in FIG. 6d, or on the surface of the substrate 610 as shown in FIG. 6e. If the device as shown in FIG. 6f is not packaged with a packaging wafer but is directly packaged with the resonant wafer and the substrate, the structure 601 for changing the electromagnetic environment can be flexibly arranged inside the substrate 610, on the surface of the substrate 610, or on the resonant wafer 630. internal. In these embodiments, the existence of the structure 601 that changes the electromagnetic environment will change the nonlinear components generated by the two resonators. When the parallel split structure is used, the effect of nonlinear cancellation will be poor, resulting in the filter’s Deterioration of nonlinear performance.

In order to overcome the above-mentioned defects of the prior art, the embodiments of the present invention propose a method for improving the nonlinear performance of an acoustic wave filter. Specific embodiments are listed below and described with reference to the accompanying drawings.

FIG. 7a shows a device plan view of the parallel split resonator with improved nonlinear performance according to the first embodiment of the present invention. The parallel split resonator of this embodiment is based on the device shown in FIG. 4 , and the shape of the connecting line 320 around the resonator 310B is mainly adjusted to at least partially cancel the nonlinear components generated by each resonator.

FIG. 7b shows a device plan view of the parallel split resonator with improved nonlinear performance according to the second embodiment of the present invention. The parallel split resonator of this embodiment is based on the device shown in Fig. 4, and the shapes of the connecting lines at both ends of the resonator 310B are adjusted so that the nonlinear components generated by each resonator are at least partially canceled.

FIG. 7c shows a device plan view of the parallel split resonator with improved nonlinear performance according to the third embodiment of the present invention. The parallel split resonator of this embodiment is based on the device shown in FIG. 4 , and the shape and size of the resonator 310B are adjusted so that the nonlinear components generated by each resonator are at least partially canceled.

FIG. 7d shows a device plan view of the parallel split resonator with improved nonlinear performance according to the fourth embodiment of the present invention. The parallel split resonator of this embodiment is based on the device shown in FIG. 4 and additionally adds a symmetric structure, that is, a connection line 360 is added on the right side. The connection line 360 can be suspended or grounded, and can also be connected in the same way as the original connection line 340 on the left side, that is, the two ends of the connection line 360 are connected to the connections at both ends of the original connection 340, as long as it helps to cancel the resonances The nonlinear components generated by the generator can be used.

When the above solution of the present invention is applied to an acoustic wave filter, the acoustic wave filter includes a plurality of piezoelectric acoustic wave resonators, and includes at least one group of parallel split resonator groups, and at least two resonators in the parallel split resonator group are connected to each other. The structure of the wire is different to at least partially cancel the nonlinear components generated by the at least two resonators. In addition, in the parallel split resonator group, at least two resonators may have different areas and/or shapes, or at least two resonators may be in the same electromagnetic environment. These structures are used to make The nonlinear components produced by the at least 2 resonators at least partially cancel. The conductors used to keep at least two resonators in the same electromagnetic environment can be arranged around the resonators (processed in the same layer as the resonators), in the substrate or substrate of the filter, or in the Inside or outside the wafer level package or plastic package of the filter. However, in the present invention, the arrangement of the conductors is not limited to the positions described above.

When one end of the parallel split resonator group is connected to a polygonal resonator, the common end of each parallel resonator is preferably connected to the same side of the polygonal resonator. Referring to FIG. 2, the resonator 102a and the resonator 102b are preferably connected to the same side of the resonator 103, and also preferably connected to the same side of the resonator 112, so as to make the flow through the resonator 102a and the resonator 102b as far as possible. The current is consistent, the balance of the circuit is improved, and the nonlinearity is offset as much as possible.

According to the technical solutions of the embodiments of the present invention, by changing the wiring structure, the area and/or shape of the resonator, the arrangement of conductors, etc., it is helpful to improve the nonlinear components generated by the parallel split resonators in the acoustic wave filter, and finally help to improve the nonlinear performance of the filter. This method is flexible to change, and has almost no impact on the size, cost and design of the filter; the impact on the chip layout and even the coupling of other structures such as substrates and substrates can also be eliminated.

The above-mentioned specific embodiments do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

A method for improving the nonlinear performance of an acoustic wave filter, the acoustic wave filter comprising a plurality of piezoelectric acoustic wave resonators, and comprising at least one group of parallel split resonator groups, characterized in that the method comprises one of the following or Multiple:

Differentiating the structure of the connection lines of the resonators in the parallel split resonator group, so that the nonlinear components generated by the resonators are at least partially canceled;

Differentiating the area and/or shape of the resonators in the parallel split resonator group to at least partially cancel the nonlinear components produced by the resonators;

Conductors are added to the filter to at least partially cancel the nonlinear components produced by the resonators.
The method according to claim 1, wherein the structure of the resonator connection line comprises one or more of the following:

The position of the wire, the length of the wire, the width of the wire, the shape and area of the wire.
The method of claim 1, wherein:

There are two resonators in the parallel split resonator group, wherein there is a first conductor near the first resonator;

The step of adding conductors includes: adding a second conductor near the second resonator in the two resonators, and making the electromagnetic environment formed by the second conductor and the second resonator be the same as the first conductor and the first resonator. The electromagnetic environment formed by the resonator is similar.
The method according to claim 3, wherein the electromagnetic environment is one or more of the following:

capacitance or mutual inductance between the connection line and the conductors near each resonator in the parallel split resonator group;

the capacitance or mutual inductance between each resonator in the parallel split resonator group and the conductor near the resonator;

Coupling capacitance or mutual inductance generated by the substrate or substrate of the acoustic wave filter.
The method of claim 3, wherein the connection manner of the second conductor is the same as the connection manner of the first conductor.
The method according to claim 1, wherein the at least one parallel split resonator group is directly connected to a signal input end or output end of the acoustic wave filter.
The method according to claim 1, wherein the step of adding conductors in the filter comprises: adding conductors in the vicinity of one or more resonators in the parallel split resonator group, adding conductors The conductors are used to place the resonators in the parallel split resonator group in a similar electromagnetic environment.
The method of claim 7, wherein the added conductor is located at one or more of the following:

The layer on which the upper or lower electrode of the resonator is located;

Substrates or substrates of filters;

Inside or outside the package structure of the filter.
The method according to any one of claims 1 to 8, wherein the number of resonators in the parallel split resonator group is an even number.
An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and including at least one group of parallel split resonator groups, characterized in that, in the acoustic wave filter:

The structures of the at least two resonators in the parallel split resonator group are different in connection, so as to at least partially cancel the nonlinear components generated by the at least two resonators.
The acoustic wave filter according to claim 10, wherein the structure of the resonator connection line includes one or more of the following: the position of the connection line, the length of the connection line, the width of the connection line, the shape and area of the connection line .
An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and comprising at least 1 group of parallel split resonator groups, it is characterized in that, in this acoustic wave filter:

In the parallel split resonator group, at least two resonators have different areas and/or shapes, so as to at least partially cancel the nonlinear components generated by the at least two resonators.
An acoustic wave filter, comprising a plurality of piezoelectric acoustic wave resonators, and including at least one group of parallel split resonator groups, characterized in that, in the acoustic wave filter, at least one group of parallel split resonator groups, the Each resonator in a parallel split resonator group is in a similar electromagnetic environment.
The acoustic wave filter according to claim 12, wherein the parallel split resonator group has additional conductors, and the added conductors are located at one or more of the following locations:

The layer on which the upper or lower electrode of the resonator is located;

Substrates or substrates of filters;

Inside or outside the package structure of the filter.
The acoustic wave filter according to any one of claims 10 to 14, wherein the at least one parallel split resonator group is located at the signal output end of the ultrasonic filter.
The acoustic wave filter according to any one of claims 10 to 15, wherein the number of resonators in the parallel split resonator group is an even number.
The acoustic wave filter according to any one of claims 10 to 16, wherein, in the parallel split resonator group, the common end of each resonator is connected to the same side of other polygonal resonators.
A multiplexer comprising the acoustic wave filter according to any one of claims 10 to 17.
A communication device, comprising the acoustic wave filter according to any one of claims 9 to 17.