阅读说明：本技术 一种滤波电路及提高滤波电路性能的方法和信号处理设备 (Filter circuit, method for improving performance of filter circuit and signal processing equipment ) 是由 庞慰 蔡华林 于 2019-10-11 设计创作，主要内容包括：本申请提供一种滤波电路及提高滤波电路性能的方法和信号处理设备。其中,滤波电路包括：多个谐振器,所述多个谐振器包括第一数量的串联谐振器和第二数量的并联谐振器,并且滤波电路的输入端连接有第一电感,滤波电路的输出端连接有第二电感,滤波电路的接地端连接有第三电感,滤波电路的第二数量的并联谐振器中包含有至少一个指定并联谐振器,所述指定并联谐振器的属性参数与其他所述并联谐振器的属性参数不同。如此,可以改善滤波电路的插损和滚降。(The application provides a filter circuit, a method for improving the performance of the filter circuit and a signal processing device. Wherein, the filter circuit includes: the resonator comprises a first number of series resonators and a second number of parallel resonators, the input end of the filter circuit is connected with a first inductor, the output end of the filter circuit is connected with a second inductor, the grounding end of the filter circuit is connected with a third inductor, the second number of parallel resonators of the filter circuit comprises at least one designated parallel resonator, and the attribute parameters of the designated parallel resonators are different from those of the other parallel resonators. Thus, the insertion loss and roll-off of the filter circuit can be improved.)

1. A filter circuit, comprising: the circuit comprises a plurality of resonators, a first inductor, a second inductor and a third inductor, wherein the plurality of resonators comprise a first number of series resonators and a second number of parallel resonators, the input end of the circuit is connected with the first inductor, the output end of the circuit is connected with the second inductor, and the grounding end of the circuit is connected with the third inductor; the method is characterized in that:

the second number of parallel resonators includes at least one designated parallel resonator, and the attribute parameters of the designated parallel resonator are different from those of the other parallel resonators.

2. The filter circuit of claim 1, wherein the attribute parameters comprise: electromechanical coupling coefficient.

3. The filter circuit of claim 1, wherein the designated parallel resonator is connected in series or in parallel with one of the parallel resonators.

4. The filter circuit according to claim 1, wherein the input terminal of the designated parallel resonator is connected to two of the series resonators, and the output terminal of the designated parallel resonator is connected to a third inductor.

5. The filter circuit of claim 3, wherein the two resonators split by the designated parallel resonator have a frequency difference and unequal area and/or shape.

6. The filter circuit of claim 1, wherein the resonator that the designated parallel resonator splits has a different structural parameter than the other parallel resonators, the structural parameters comprising: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

7. A signal processing apparatus characterized by comprising: a signal input circuit, a signal output circuit and a filter circuit as claimed in any one of claims 1 to 6; the signal input circuit is connected with the filter circuit, and the filter circuit is connected with the signal output circuit.

8. A method of improving performance of a filter circuit, the filter circuit comprising: the circuit comprises a plurality of resonators, a first inductor, a second inductor and a third inductor, wherein the plurality of resonators comprise a first number of series resonators and a second number of parallel resonators, the input end of the circuit is connected with the first inductor, the output end of the circuit is connected with the second inductor, and the grounding end of the circuit is connected with the third inductor; characterized in that the method comprises:

and setting at least one specified parallel resonator in the second number of parallel resonators to have different attribute parameters from the attribute parameters of the other parallel resonators.

9. The method of claim 8, wherein the attribute parameters comprise: electromechanical coupling coefficient.

10. The method of claim 8, further comprising: and connecting the specified parallel resonator with one of the parallel resonators in series or in parallel.

11. The method of claim 8, further comprising: and connecting the input end of the specified parallel resonator with the two series resonators, and connecting the output end of the specified parallel resonator with a third inductor.

12. The method of claim 10, further comprising: two resonators which are split by the parallel resonator are arranged to have different frequency difference and have different areas and/or shapes.

13. The method of claim 8, further comprising: setting the structural parameters of the resonator split by the specified parallel resonator to be different from the structural parameters of the other parallel resonators, wherein the structural parameters comprise: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

Technical Field

The present disclosure relates to the field of circuit element technologies, and in particular, to a filter circuit, a method for improving performance of the filter circuit, and a signal processing device.

Background

In a wireless communication system, as the utilization rate of frequency bands is higher and higher, the transition band between the frequency bands is narrower and narrower. In order to ensure the insertion loss of the filter and the suppression of adjacent frequency bands, the roll-off requirement of the filter is higher and higher. The filter has the characteristic of high Q value, so that the filter has better roll-off and insertion loss advantages compared with LC (resonance circuit), SAW (surface acoustic wave), surface acoustic wave filter and the like, but with the further improvement of performance requirements, better performance is difficult to obtain only by depending on the high Q value advantage of the filter. Therefore, there is a need to improve the performance of filters over the circuit topology.

Disclosure of Invention

In view of the above, the present application provides a filter circuit, a method for improving performance of the filter circuit, and a signal processing apparatus, so as to improve performance of the filter circuit.

Specifically, the method is realized through the following technical scheme:

in a first aspect, an embodiment of the present application provides a filter circuit, where the filter circuit includes: the circuit comprises a plurality of resonators, a first inductor, a second inductor and a third inductor, wherein the plurality of resonators comprise a first number of series resonators and a second number of parallel resonators, the input end of the circuit is connected with the first inductor, the output end of the circuit is connected with the second inductor, and the grounding end of the circuit is connected with the third inductor; the second number of parallel resonators includes at least one designated parallel resonator, and the attribute parameters of the designated parallel resonator are different from those of the other parallel resonators.

Optionally, the attribute parameters include: electromechanical coupling coefficient.

Optionally, the designated parallel resonator is connected in series or in parallel with one of the parallel resonators.

Optionally, the input end of the designated parallel resonator is connected to two of the series resonators, and the output end of the designated parallel resonator is connected to the third inductor.

Optionally, the two resonators split by the designated parallel resonator have a frequency difference and have unequal areas and/or shapes.

Optionally, the structural parameters of the specified parallel resonator are different from the structural parameters of the other parallel resonators, and the structural parameters include: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

In a second aspect, an embodiment of the present application provides a signal processing apparatus, including: a signal input circuit, a signal output circuit, and a filter circuit as described in the first aspect; the signal input circuit is connected with the filter circuit, and the filter circuit is connected with the signal output circuit.

In a third aspect, an embodiment of the present application provides a method for improving performance of a filter circuit, where the filter circuit includes: the circuit comprises a plurality of resonators, a first inductor, a second inductor and a third inductor, wherein the plurality of resonators comprise a first number of series resonators and a second number of parallel resonators, the input end of the circuit is connected with the first inductor, the output end of the circuit is connected with the second inductor, and the grounding end of the circuit is connected with the third inductor; the method comprises the following steps:

and setting at least one specified parallel resonator in the second number of parallel resonators to have different attribute parameters from the attribute parameters of the other parallel resonators.

Optionally, the attribute parameters include: electromechanical coupling coefficient.

Optionally, the method further comprises: and arranging the specified parallel resonator and one parallel resonator in series or in parallel.

Optionally, the method further comprises: and setting the input end of the specified parallel resonator to be connected with the two series resonators, and setting the output end of the specified parallel resonator to be connected with a third inductor.

Optionally, the method further comprises: two resonators which are split by the designated parallel resonator are arranged to have a slight frequency difference and unequal areas and/or shapes.

Optionally, the method further comprises: setting the structural parameters of the resonator split by the specified parallel resonator to be different from the structural parameters of the other parallel resonators, wherein the structural parameters comprise: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

According to the filter circuit, the method for improving the performance of the filter circuit and the signal processing equipment, the designated parallel resonators are arranged in the filter, the attribute parameters of the designated parallel resonators are differentiated from the attribute parameters of other parallel resonators, the insertion loss and the roll-off of the filter circuit can be obviously improved, and the better performance of the filter circuit in the prior art is obtained.

Drawings

Fig. 1 is a schematic diagram of a filter circuit in the prior art.

Fig. 2a is a schematic diagram illustrating a first filter circuit according to an exemplary embodiment of the present application;

FIG. 2b is an impedance schematic of a first filter circuit shown in an exemplary embodiment of the present application;

FIG. 3 is a schematic diagram of another filter circuit according to an exemplary embodiment of the present application;

FIG. 4 is a schematic diagram of a structure of an upper electrode of a resonator according to an exemplary embodiment of the present application;

FIG. 5a is a graph illustrating a comparison of the global curves before and after parallel splitting according to an exemplary embodiment of the present application;

fig. 5b is a graph illustrating the comparison of Rs at Fs frequencies before and after parallel splitting according to an exemplary embodiment of the present application;

FIG. 5c is a graph showing the comparison of Rp before and after tandem splitting at Fp in accordance with an exemplary embodiment of the present application;

FIG. 5d is a schematic diagram illustrating the effect of using parallel splitting according to an exemplary embodiment of the present application;

FIG. 5e is a schematic diagram illustrating the effect of using parallel splitting according to an exemplary embodiment of the present application;

fig. 6 is a resonator disassembly schematic.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

Fig. 1 is a schematic diagram of a filter circuit in the prior art. Referring to fig. 1, a filter circuit in the related art includes a plurality of resonators, the plurality of resonators includes a first number of series resonators 20 and a second number of parallel resonators 40, which includes 5 series resonators 20 and 4 parallel resonators 40 as an example, and an input end of the filter circuit is connected to a first inductor 10, an output end of the filter circuit is connected to a second inductor 30, ground ends of the filter circuit are respectively connected to third inductors 50, and one end of each third inductor 50 is connected to a parallel resonator and the other end is grounded.

In the filter circuit provided in the embodiment of the present application, a difference between the attribute parameter of the series resonator and the attribute parameter of the parallel resonator is greater than a preset value. For example, in an embodiment of the present application, referring to fig. 2a, fig. 2a is a schematic structural diagram of a first filter circuit shown in an exemplary embodiment of the present application, in the filter circuit of fig. 2a, a designated parallel resonator 60 is provided, an input end of the designated parallel resonator 60 is connected to two series resonators, an output end of the designated parallel resonator 60 is connected to a third inductor, and an electromechanical coupling coefficient of the designated parallel resonator 60 is different from electromechanical coupling coefficients of other parallel resonators. This helps to improve the performance of the filter, and is described below with reference to fig. 2b, which is a schematic impedance diagram of a first filter circuit according to an exemplary embodiment of the present application.

Fig. 2b shows the relationship between the frequency and the impedance of the combined resonator in fig. 2a, the dashed line is the impedance diagram of the resonator in the prior art, and the solid line is the impedance diagram of the new combined structure proposed in this embodiment, wherein for the parallel resonator, two low impedances are formed as the zero point of out-of-band rejection, and the position of the out-of-band zero point is more advanced than that in the prior art, so that the roll-off on the left side can be better improved.

In another embodiment of the present invention, the specified parallel resonator 60 may be connected in series or in parallel with a parallel resonator; fig. 3 is a schematic structural diagram of another filter circuit, and referring to fig. 3, in this embodiment, a specified parallel resonator 60 is taken as an example, the specified parallel resonator 60 is connected in series with a parallel resonator, specifically, an input end of the specified parallel resonator 60 is connected with two series resonators, and an output end of the specified parallel resonator 60 is connected with a parallel resonator.

It should be noted that, in the embodiment of the present invention, a specific parallel resonator such as the specific parallel resonator 60 described above may be connected in series with any one of the parallel resonators, and the number of the specific parallel resonators may be plural, and the specific parallel resonator may be provided on a branch where any one of the parallel resonators and the third inductor are located.

Optionally, the designated parallel resonator is obtained by adopting a split mode of different frequencies and different areas. The area and frequency of two resonators split in parallel in this application, and even the structure, can be different. The number of splits is not limited to 2, but may be three or even more than three.

Referring to fig. 6, the upper left of the figure is a single resonator, the two upper right represent a series split, and the lower represents a parallel split. Generally, the area and frequency of two resonators split in series and parallel are the same, and the area and frequency, even the structure, of the two resonators split in series and parallel in the application can be different. The number of splits is not limited to 2, but may be three or even more than three.

In this embodiment, the present embodiment has the following positive effects: the process manufacturing reliability is ensured; the nonlinear splitting ensures that the nonlinear performance of the device is better: power splitting, in the case of high power application, multiple resonators are used for splitting to reduce power distribution; the layout is more flexible, the die area is favorably fully utilized, diesize is reduced, the space for filling the chip can be better through the flexible design of the area, and the more compact arrangement is favorably realized, so that the chip area can be fully utilized, and the chip cost is favorably reduced.

Optionally, the structural parameters of the specified series resonator are different from the structural parameters of the other series resonators, and the structural parameters include: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

In this embodiment, the difference in the electromechanical coupling coefficient is changed by changing the annular protrusion structure, the recess structure, the suspended wing structure, and the like of the resonator, and in addition, the distribution of the Q value of the resonator can be adjusted by changing the annular protrusion structure, the recess structure, and the suspended wing structure of the resonator, and for a specific performance index, an ideal performance can be obtained by adjusting the distribution of the Q value.

FIG. 4 is a schematic diagram of a structure of an upper electrode of a resonator according to an exemplary embodiment of the present application; referring to fig. 4, the upper electrode of the resonator includes: the protruding structures, the recessed structures, and the suspension wing structures, as shown in fig. 4 in particular, range a represents the suspension wing structure; range b represents a convex structure; the range c indicates a concave structure. Fig. 4 is a top view of the upper electrode on the left and a cross-sectional view of the upper electrode on the right. In a plan view, the area with oblique lines inside is a concave structure, the annular areas where the two arrows above are located are a convex structure and a suspended wing structure respectively, and the annular area at the outermost circle is the suspended wing structure. The smaller the width between the convex structure and the concave structure of the upper electrode is, the smaller the electromechanical coupling coefficient is; the larger the width of the annular convex structure is, the smaller the electromechanical coupling coefficient is; the larger the width of the suspended wing structure, the smaller the electromechanical coupling coefficient. Therefore, the electromechanical coupling coefficient can be changed by controlling the width of each structure. Meanwhile, the width of each structure influences the distribution of Q values, and better performance under a specific electromechanical coupling coefficient can be obtained through selection of a proper structure. Fig. 5a, 5b, 5c show the effect of the adjustment of the distribution of the Q value.

Specifically, fig. 5a is a schematic diagram of a comparison result of the whole curves before and after the parallel splitting shown in an exemplary embodiment of the present application, and except for the impedances at the points Fs and Fp, the remaining impedances are substantially unchanged, so that when the parallel splitting is actually performed, other performances of the filter are not affected. The solid line is after splitting and the dotted line is before splitting.

Fig. 5b is a graph showing the comparison result of Rs at Fs frequencies before and after parallel splitting according to an exemplary embodiment of the present application, and it can be seen from fig. 5b that after splitting, Rs is significantly reduced, and the reduction of Rs is significantly improved on the left side of the passband. The solid line is after splitting and the dotted line is before splitting.

Fig. 5c is a graph showing the comparison of Rp before and after the tandem splitting at Fp according to an exemplary embodiment of the present application, and it can be seen from fig. 5c that after the splitting, Rp is significantly reduced, and the reduction of Rp deteriorates the right side of the passband. The solid line is after splitting and the dotted line is before splitting.

Fig. 5d is a diagram illustrating the effect of using a parallel split that improves Rs, which improves the left side of the passband, according to an exemplary embodiment of the present application. When the left side of the filter has higher index requirements, the required performance can be obtained by parallel splitting.

The effect of the change in the electromechanical coupling coefficient of two resonators split in parallel is shown in fig. 5e, where the solid line is improved and the dashed line is the previous, and from the above figure it can be seen that the roll-off is improved by 2.5MHz for the same rejection (say-50 dB).

An embodiment of the present application further provides a method for improving performance of a filter circuit, which is used to obtain the filter circuit described in any of the above embodiments. The filter circuit includes: the circuit comprises a plurality of resonators, a first inductor, a second inductor and a third inductor, wherein the plurality of resonators comprise a first number of series resonators and a second number of parallel resonators, the input end of the circuit is connected with the first inductor, the output end of the circuit is connected with the second inductor, and the grounding end of the circuit is connected with the third inductor; the method comprises the following steps A10:

step a10, setting at least one attribute parameter of a specified parallel resonator in the second number of parallel resonators to be different from the attribute parameters of the other parallel resonators.

In the embodiment, the filter is provided with the characteristic parameters of the specified parallel resonator and the characteristic parameters of other parallel resonators which are differentiated, so that the insertion loss and the roll-off of the frequency wave circuit can be obviously improved, and the performance of the filter circuit is better than that of the filter circuit in the prior art.

In an embodiment of the present application, the attribute parameters include: electromechanical coupling coefficient.

In an embodiment of the present application, the method further includes: the specified parallel resonator is arranged in series with one of the parallel resonators.

It should be noted that, in the embodiment of the present invention, the specified parallel resonator may be connected in series with any one of the resonators, and the number of the specified parallel resonators may be multiple, and each of the specified parallel resonators is respectively disposed on a branch where any one of the parallel resonators and the third inductor are located; or the plurality of parallel resonators are simultaneously connected in series on a branch circuit where one parallel resonator and the third inductor are located.

In an embodiment of the present application, the method further includes: and setting the input end of the specified parallel resonator to be connected with the two series resonators, and setting the output end of the specified parallel resonator to be connected with a third inductor. Thereby improving the performance of the filter.

In an embodiment of the present application, the method further includes: and setting the specified parallel resonator to be obtained by adopting a split mode of different frequencies and different areas.

Furthermore, the area of the electrode of the designated parallel resonator is different from the area of the electrode of the parallel resonator connected in series with the designated parallel resonator, so that the space for filling the chip can be designed better flexibly through the area, and the more compact arrangement is facilitated, therefore, the area of the chip can be fully utilized, and the chip cost is reduced.

In an embodiment of the present application, the method further includes: setting the structural parameters of the specified parallel resonator to be different from the structural parameters of the other parallel resonators, wherein the structural parameters comprise: and any one or more of the annular convex structure width, the concave structure width and the suspended wing structure width of the upper electrode.

The difference of the electromechanical coupling coefficients is changed by changing the annular convex structure, the concave structure, the suspended wing structure and the like of the resonator, in addition, the Q value distribution of the resonator can be adjusted by changing the annular convex structure, the concave structure and the suspended wing structure of the resonator, and for a specific performance index, ideal performance can be obtained by adjusting the Q value distribution.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.