WO2021068669A1

WO2021068669A1 - Filter circuit, method for improving performance of filter circuit, and signal processing device

Info

Publication number: WO2021068669A1
Application number: PCT/CN2020/111341
Authority: WO
Inventors: 庞慰; 蔡华林
Original assignee: 天津大学; 诺思(天津)微系统有限责任公司
Priority date: 2019-10-11
Filing date: 2020-08-26
Publication date: 2021-04-15
Also published as: CN110798166A

Abstract

The present application provides a filter circuit, a method for improving the performance of a filter circuit, and a signal processing device. The filter circuit comprises: a plurality of resonators. 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 to a first inductor, the output end of the circuit is connected to a second inductor, and the grounding end of the circuit is connected to a third inductor. The second number of parallel resonators comprise at least one specified parallel resonator, the attribute parameters of the specified parallel resonator are different from those of other parallel resonators, and the attribute parameters comprise frequency. In this way, the insertion loss and roll-off of the filter circuit can be improved.

Description

Filter circuit and method for improving filter circuit performance and signal processing equipment

Technical field

This application relates to the technical field of circuit elements, and in particular to a filter circuit and a method and signal processing equipment for improving the performance of the filter circuit.

Background technique

In the wireless communication system, due to the increasing utilization of frequency bands, the transition band between various frequency bands is getting narrower and narrower. In order to ensure the insertion loss of the filter and the suppression of adjacent frequency bands, the roll-off requirements of the filter are getting higher and higher. Because the filter has the characteristics of high Q value, it has better roll-off and insertion loss advantages than LC (resonant circuit) and SAW (surface acoustic wave, surface acoustic wave filter), but with further performance requirements To improve, it is difficult to obtain better performance only by relying on the high Q value of the filter. Therefore, it is necessary to improve the performance of the filter in the circuit topology.

Summary of the invention

In view of this, the present application provides a filter circuit, a method for improving the performance of the filter circuit, and a signal processing device to improve the performance of the filter circuit.

Specifically, this application is implemented through the following technical solutions:

In a first aspect, an embodiment of the present application provides a filter circuit, the filter circuit includes: a plurality of resonators, the plurality of resonators include a first number of series resonators and a second number of parallel resonators, And the input end of the circuit is connected with a first inductance, the output end of the circuit is connected with a second inductance, and the ground end of the circuit is connected with a third inductance; the second number of parallel resonators includes at least A designated parallel resonator, the attribute parameter of the split resonator of the designated parallel resonator is different from the attribute parameters of other parallel resonators, and the attribute parameter includes: the frequency of the resonator.

Optionally, the designated parallel resonator is connected in series or in parallel with a parallel resonator.

Optionally, the input end of the designated parallel resonator is connected to the two 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.

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

In a third aspect, an embodiment of the present application provides a method for improving the performance of a filter circuit. The filter circuit includes a plurality of resonators, and the plurality of resonators includes a first number of series resonators and a second number of series resonators. Parallel resonators, and the input terminal of the circuit is connected with a first inductor, the output terminal of the circuit is connected with a second inductor, and the ground terminal of the circuit is connected with a third inductor; the method includes:

At least one designated parallel resonator is provided in the second number of parallel resonators, and the attribute parameters of the split resonator of the designated parallel resonator are different from those of other parallel resonators, and the attribute parameters include : The frequency of the resonator.

Optionally, the method further includes: the designated parallel resonator is connected in series or in parallel with a parallel resonator.

Optionally, the method further includes: connecting an input end of the designated parallel resonator to two of the series resonators, and connecting an output end of the designated parallel resonator to a third inductor.

Optionally, the method further includes: setting the two resonators split by the designated parallel resonator to have a frequency difference and have unequal areas and/or shapes.

The filter circuit, the method for improving the performance of the filter circuit, and the signal processing device provided by the embodiments of the present application are provided by providing at least one designated parallel resonator in the second number of parallel resonators, and the frequency of the designated parallel resonator is The frequency of the parallel resonator is different from that of other parallel resonators, which can significantly improve the insertion loss and roll-off of the filter circuit, thereby obtaining better performance than the filter circuit in the prior art.

Description of the drawings

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

Fig. 2a is a schematic structural diagram of a first filter circuit shown in an exemplary embodiment of the present application;

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

2c is a schematic diagram of the roll-off improvement effect of the first filter circuit shown in an exemplary embodiment of the present application;

Fig. 3 is a schematic structural diagram of a second filter circuit shown in an exemplary embodiment of the present application;

Fig. 4a is a schematic structural diagram of a third filter circuit shown in an exemplary embodiment of the present application;

FIG. 4b is a schematic diagram of impedance of a third filter circuit shown in an exemplary embodiment of the present application;

Fig. 5 is a schematic structural diagram of a fourth filter circuit shown in an exemplary embodiment of the present application;

Fig. 6a is a schematic structural diagram of a fifth filter circuit shown in an exemplary embodiment of the present application;

Fig. 6b is a schematic diagram of impedance of a fifth filter circuit shown in an exemplary embodiment of the present application;

Fig. 7 is a schematic structural diagram of a sixth filter circuit shown in an exemplary embodiment of the present application;

Fig. 8 is a schematic structural diagram of a sixth filter circuit shown in an exemplary embodiment of the present application;

Fig. 9a is a schematic structural diagram of a seventh filter circuit shown in an exemplary embodiment of the present application;

Fig. 9b is a schematic diagram of impedance of a seventh filter circuit shown in an exemplary embodiment of the present application;

FIG. 9c is a schematic diagram showing a roll-off improvement effect of a seventh filter circuit according to an exemplary embodiment of the present application;

FIG. 10a is a schematic diagram showing the comparison result of the overall curves before and after parallel splitting according to an exemplary embodiment of the present application; FIG.

FIG. 10b is a schematic diagram showing the comparison result of Rs at the Fs frequency before and after parallel splitting according to an exemplary embodiment of the present application;

FIG. 10c is a schematic diagram showing a comparison result of Rp at Fp before and after serial splitting according to an exemplary embodiment of the present application; FIG.

Figure 11 is a schematic diagram of the resonator split.

Detailed ways

The exemplary embodiments will be described in detail here, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the application as detailed in the appended claims.

Fig. 1 is a schematic structural diagram of a filter circuit in the prior art. 1, the filter circuit in the prior art includes a plurality of resonators, the plurality of resonators include a first number of series resonators 20 and a second number of parallel resonators 40, the figure includes 5 Take the series resonator 20 and the four parallel resonators 40 as an example, and the input end of the filter circuit is connected to the first inductor 10, the output end of the filter circuit is connected to the second inductor 30, and the ground end of the filter circuit is respectively connected to the third inductor. Inductors 50, one end of each third inductance 50 is connected to the parallel resonator, and the other end is grounded.

Figure 2a is a schematic structural diagram of the first filter circuit shown in an exemplary embodiment of the present application; referring to Figure 2a, in the filter circuit provided in this embodiment, a designated series resonator 70 is provided, and the designated series resonance The input terminal and the output terminal of the device 70 are respectively connected to a parallel resonator, and the electromechanical coupling coefficient of the designated series resonator 70 is different from the electromechanical coupling coefficient of other series resonators.

Furthermore, in this embodiment, the insertion loss and roll-off are improved by setting the first number of series resonators to include one or more designated series resonators 70 with different electromechanical coupling coefficients. It will be described below with reference to FIG. 2b. FIG. 2b is a schematic diagram of the impedance of the first filter circuit shown in an exemplary embodiment of the present application.

In the embodiments of the present application, FIG. 2b shows the relationship between the frequency and 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 proposed in the embodiment of the present application. The impedance diagram of the new combined structure, in which for the series resonator, the two high impedances formed are used as the zero points for out-of-band suppression. It can be seen from the figure that the position of the out-of-band zero point is more advanced than the one that only changes the frequency, which can better improve the right roll-off.

Specifically, FIG. 2c shows a schematic diagram of the roll-off improvement effect of the above-mentioned first filter circuit; referring to FIG. 4c, the solid line is the roll-off curve of the first filter circuit in this embodiment, and the dashed line is the existing For the roll-off curve of the filter circuit in the technology, it can be clearly seen that the third filter circuit provided in the embodiment of the present application improves the roll-off by 1.5 MHz for the same suppression (for example, -50 dB).

FIG. 3 is a schematic structural diagram of a second type of filter circuit shown in an exemplary embodiment of the present application. Referring to FIG. 3, this embodiment includes a designated series resonator 70, and the designated series resonator 70 is connected to a series resonator. After the devices are connected in series, they are connected to the parallel resonator respectively. Specifically, referring to FIG. 3, the input end of the designated series resonator 70 is connected to a parallel resonator and a series resonator, and the output end of the designated series resonator is only connected to another series resonator.

It should be noted that the number and connection positions of the above-mentioned designated series resonators in this embodiment can be arbitrary, which is not limited in this application.

In an embodiment of the present application, the second number of parallel resonators includes at least one designated parallel resonator, and the electromechanical coupling coefficient of the designated parallel resonator is different from the electromechanical coupling coefficient of other parallel resonators.

FIG. 4a is a schematic structural diagram of a third filter circuit shown in an exemplary embodiment of the present application. Referring to FIG. 4a, in the filter circuit provided in this embodiment, a designated parallel resonator 60 is provided, and the designated parallel resonator The input end of the designated parallel resonator 60 is connected to two series resonators, and the output end of the designated parallel resonator 60 is connected to the third inductance. The electromechanical coupling coefficient of the designated parallel resonator 60 is different from that of other parallel resonators.

4b is the impedance diagram of the third filter shown in FIG. 4a, the dashed line is the impedance diagram of the resonator in the prior art, and the solid line is the impedance diagram of the combined structure in this embodiment. In terms of the device, the two low impedances formed are used as the zero points for out-of-band suppression, and the position of the out-of-band zero point is more advanced than in the prior art, which can better improve the left roll-off.

In another embodiment of the present invention, the above-mentioned designated parallel resonator 60 may be connected in series with a parallel resonator; FIG. 5 is a schematic structural diagram of a fourth filter circuit shown in an exemplary embodiment of the present application. In this embodiment, it is taken as an example that a designated parallel resonator 60 is included. The designated parallel resonator 60 is connected in series with a parallel resonator. Specifically, the input end of the designated parallel resonator 60 is connected with two series resonators. , The output terminal of the designated parallel resonator 60 is connected to a parallel resonator.

It should be noted that in this embodiment, the designated parallel resonator can be connected in series with any parallel resonator, and the number of the designated parallel resonator can be multiple, and the designated parallel resonator can be set in any one of the parallel resonators. The branch where the parallel resonator and the third inductor are located. In another embodiment of the present application, the aforementioned attribute parameter is the frequency of the resonator.

Optionally, the above-mentioned first number of series resonators includes at least one designated series resonator, and the resonator frequency of the designated series resonator is different from the frequencies of other series resonators.

Fig. 6a is a schematic structural diagram of a fifth filter circuit shown in an exemplary embodiment of the present application. Referring to Fig. 6a, in the filter circuit provided in this embodiment, a designated series resonator 70 is provided. The input terminal and the output terminal of the device 70 are respectively connected to a parallel resonator, and the frequency of the designated series resonator 70 is different from the frequencies of other series resonators.

Furthermore, in this embodiment, the insertion loss and roll-off are improved by setting the first number of series resonators to include one or more designated series resonators 70 with different frequencies.

Fig. 6b shows the impedance diagram of the fifth filter circuit shown in Fig. 6a. With reference to Fig. 6b, the dashed line is the impedance diagram of the resonator in the prior art, and the solid line is the new one proposed in this embodiment. The impedance diagram of the combined structure. For the series resonator, the two high impedances formed are used as the zero points for out-of-band suppression, and the position of the out-of-band zero points is earlier than the original one, which can improve the roll-off on the right.

FIG. 7 is a schematic structural diagram of a sixth filter circuit shown in an exemplary embodiment of the present application. Referring to FIG. 7, in this embodiment, the first number of series resonators includes a designated series resonator 70, which The frequency of the designated series resonator 70 is different from the frequencies of the other series resonators 20. And the two ends of the designated resonator 70 are respectively connected to the series resonator and the parallel resonator.

Specifically, the input end of the designated series resonator 70 is connected to a parallel resonator and a series resonator, and the output end of the designated series resonator is connected to only one series resonator.

In another embodiment of the present invention, the second number of parallel resonators includes at least one designated parallel resonator, and the resonator frequency of the designated parallel resonator is different from the attribute parameters of the other parallel resonators.

Optionally, the aforementioned designated parallel resonator 60 may be connected in series with a parallel resonator; FIG. 8 is a schematic structural diagram of a sixth filter circuit shown in an exemplary embodiment of this application. Taking as an example a designated parallel resonator 60, the designated parallel resonator 60 is connected in series with a parallel resonator. Specifically, the input end of the designated parallel resonator 60 is connected to two series resonators, and the designated parallel resonator 60 is connected in series. The output terminal of the resonator 60 is connected to a parallel resonator. The resonator frequency of the designated parallel resonator 60 is different from the resonator frequencies of other parallel resonators.

Optionally, the designated parallel resonator is obtained by splitting the difference frequency with unequal area. Referring to Figure 10, the left side of the upper figure in the figure is a single resonator, the two upper ones on the right represent series splitting, and the lower one represents parallel splitting. The area, frequency and even structure of the two resonators split in series or in parallel in the parallel resonator in this application can be different. The number of splits is not limited to two, but can also be three or more than three.

In this embodiment, this embodiment has the following positive effects: ensuring process manufacturing reliability; non-linear splitting ensures better non-linear performance of the device: power splitting, in high-power applications, multiple resonators will be used to perform Split to reduce power distribution; layout layout is more flexible, which is conducive to making full use of die area and reducing diesiz.

Fig. 10a is a schematic diagram showing the comparison result of the overall curve before and after parallel splitting according to an exemplary embodiment of the present application. Except for the impedances at points Fs and Fp, the other impedances are basically unchanged. Therefore, when the actual splitting is performed, the other impedances of the filter are not changed. There is no impact on performance. The solid line is after splitting, and the dashed line is before splitting.

Figure 10b is a schematic diagram showing the comparison result of Rs at the Fs frequency before and after parallel splitting according to an exemplary embodiment of the present application. It can be seen from Figure 5b that after splitting, Rs is significantly reduced, and the decrease of Rs affects the left of the passband. There is a significant improvement on the side. The solid line is after splitting, and the dashed line is before splitting.

Fig. 10c is a schematic diagram showing the comparison result of Rp at Fp before and after the serial splitting according to an exemplary embodiment of the present application. It can be seen from Fig. 5c that after splitting, Rp is significantly reduced, and the reduction of Rp affects the right side of the passband. There is deterioration. The solid line is after splitting, and the dashed line is before splitting.

Optionally, in parallel splitting, the frequency can be adjusted through the convex structure, the concave structure, the suspended wing structure or the mass load, including other ways of adjusting the frequency, to correspondingly improve the roll-off and insertion loss on the left side. Fig. 9a is a schematic structural diagram of a seventh filter circuit shown in an exemplary embodiment of the present application. Referring to Fig. 9a, in the filter circuit provided in this embodiment, a designated parallel resonator 60 is provided. The input end of the resonator 60 is connected to two series resonators, the output end of the designated parallel resonator 60 is connected to the third inductor, and the resonator frequency of the designated parallel resonator 60 is the same as that of other parallel resonators. different.

Figure 9b is a schematic diagram of the impedance of the seventh filter circuit shown in Figure 9a, the dashed line is the impedance diagram of the resonator in the prior art, and the solid line is the schematic diagram of the impedance of the combined structure proposed in this embodiment. In other words, the two low impedances formed are used as zero points for out-of-band suppression. It can be seen from the above figure that the position of the out-of-band zero point is earlier than the original, which can improve the left roll-off.

Fig. 9c is a schematic diagram of the roll-off improvement effect of the filter circuit shown in Fig. 9a; referring to Fig. 9c, the solid line is the roll-off curve of the filter circuit in this embodiment, and the dashed line is the roll-off curve of the filter circuit in the prior art The curve can be clearly obtained. The filter circuit provided in the embodiment of the present application improves the roll-off of the same suppression (for example -50dB) by 2MHz.

Optionally, the frequency difference between the aforementioned parallel resonators may be realized by adding an additional metal layer to the upper electrode of the split parallel resonator. Exemplarily, the upper electrode of the designated parallel resonator electrode is provided with a first additional metal layer.

Optionally, the area of the designated parallel resonator electrode is different from the area of the parallel resonator electrode connected in series.

In this embodiment, by setting the area of the electrode of the designated parallel resonator to be different from the area of the electrode of the parallel resonator connected in series, it is possible to better fill the space of the chip through the flexible design of the area, which is conducive to tighter arrangement Therefore, the chip area can be fully utilized, which helps to reduce the cost of the chip.

An embodiment of the present invention also provides a signal processing device, including: a signal input circuit, a signal output circuit, and any one of the foregoing filter circuits; the signal input circuit is connected to the filter circuit, and the filter circuit is connected to The signal output circuit is connected.

The signal processing device provided in this embodiment has better roll-off and insertion loss performance, so the signal processing effect is better.

An embodiment of the present application also provides a method for improving the performance of a filter circuit. The filter circuit includes a plurality of resonators, and the plurality of resonators includes a first number of series resonators and a second number of parallel resonances. The input terminal of the circuit is connected with a first inductor, the output terminal of the circuit is connected with a second inductor, and the ground terminal of the circuit is connected with a third inductor; the method includes:

At least one designated parallel resonator is set in the second number of parallel resonators, the attribute parameter of the designated parallel resonator is different from the attribute parameters of other parallel resonators, and the attribute parameter includes: the frequency of the resonator .

In this embodiment, by providing at least one designated parallel resonator in the second number of parallel resonators, and the frequency of the designated parallel resonator is different from that of other parallel resonators, the performance of the filter circuit can be significantly improved. Insertion loss and roll-off, thereby obtaining better performance than the filtering circuit in the prior art.

Optionally, the method further includes: the designated parallel resonator is connected in series with a parallel resonator.

It should be noted that in this embodiment, the designated parallel resonator can be set in series with any parallel resonator, and the number of designated parallel resonators can be multiple, and the designated parallel resonator can be set On any branch where the parallel resonator and the third inductor are located.

Optionally, the above method further includes: connecting the input end of the designated parallel resonator to the two series resonators, and connecting the output end of the designated parallel resonator to the third inductor.

Optionally, the above method further includes: setting the designated parallel resonator to be obtained by a splitting method with unequal area of difference frequency.

Optionally, the above method further includes: disposing a first additional metal layer or other mass load materials on the upper electrode of the designated parallel resonator electrode.

It should be noted that in this embodiment, the designated parallel resonator can be connected in series with any parallel resonator, and the number of the designated parallel resonator can be multiple, and the designated parallel resonator can be set in any one of the parallel resonators. The branch where the parallel resonator and the third inductor are located.

Optionally, the filter circuit described in the foregoing embodiment of the present application may include both a designated series resonator and a designated parallel resonator, which is not limited in the present invention.

The above are only the preferred embodiments of this application and are not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in this application Within the scope of protection.

Claims

A filter circuit includes: a plurality of resonators, the plurality of resonators include a first number of series resonators and a second number of parallel resonators, and the input of the circuit is connected with the first Inductance, a second inductance is connected to the output end of the circuit, and a third inductance is connected to the ground end of the circuit; characterized in that:

The second number of parallel resonators includes at least one designated parallel resonator, and the attribute parameters of the split resonator of the designated parallel resonator are different from those of other parallel resonators, and the attribute parameters include: The frequency of the resonator.
The filter circuit according to claim 1, wherein the designated parallel resonator is connected in series or in parallel with a parallel resonator.
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.
The filter circuit according to claim 2, wherein the two resonators split by the designated parallel resonator have a frequency difference and have unequal areas and/or shapes.
A signal processing device, comprising: a signal input circuit, a signal output circuit, and the filter circuit according to any one of claims 1-4; the signal input circuit is connected to the filter circuit, and the filter The circuit is connected to the signal output circuit.
A method for improving the performance of a filter circuit, the filter circuit comprising: a plurality of resonators, the plurality of resonators including a first number of series resonators and a second number of parallel resonators, and an input end of the circuit A first inductor is connected, the output terminal of the circuit is connected with a second inductor, and the ground terminal of the circuit is connected with a third inductor; characterized in that, the method includes:

At least one designated parallel resonator is set in the second number of parallel resonators, and the attribute parameters of the split resonator of the designated parallel resonator are different from those of other parallel resonators, and the attribute parameters include : The frequency of the resonator.
The method according to claim 6, further comprising: connecting the designated parallel resonator and a parallel resonator in series or parallel.
The method according to claim 6, further comprising: connecting the input end of the designated parallel resonator to the two series resonators, and the output end of the designated parallel resonator is connected to the third inductor. Connected.
8. The method according to claim 7, further comprising: setting the two resonators split by the designated parallel resonator to have a frequency difference and have unequal areas and/or shapes.