WO2020125214A1

WO2020125214A1 - Multi-channel filter and components thereof, and electronic device

Info

Publication number: WO2020125214A1
Application number: PCT/CN2019/114250
Authority: WO
Inventors: 庞慰; 边子鹏; 郑云卓
Original assignee: 天津大学; 诺思(天津)微系统有限责任公司
Priority date: 2018-12-18
Filing date: 2019-10-30
Publication date: 2020-06-25
Also published as: CN111342811A; CN111342811B

Abstract

A multi-channel filter, comprising: a series resonator branch comprising multiple series resonator units, each series resonator unit comprising n series resonators having different mass loads and connected in parallel, wherein n is a natural number not less than 2; and a parallel resonator branch comprising multiple parallel resonator units, wherein each parallel resonator unit comprises parallel resonators connected in series, and at least one parallel resonator unit comprises n parallel resonators having different mass loads. The ith series resonators in the series resonator units constitute an ith group of series resonators, resonators in the ith group of series resonators all have the ith mass loads connected in series, and i is a natural number and 1≤i≤n; the ith parallel resonators in all the parallel resonator units constitute an ith group of parallel resonators, and resonators in the ith group of parallel resonators all have the ith mass loads connected in parallel; the ith group of series resonators and the ith group of parallel resonators together constitute an ith frequency pass band; the mass loads of the n series resonators are different from one another, and the mass loads of the n parallel resonators are different from one another.

Description

Multi-channel filter and its components, electronic equipment

Technical field

Embodiments of the present invention relate to the semiconductor field, and in particular, to a multi-channel filter, a component with the filter, and an electronic device with the above filter or component.

Background technique

With the development of wireless communication applications, people have higher and higher requirements for data transmission rate. Corresponding to the data transmission rate is the high utilization rate of spectrum resources and the complexity of spectrum. The complexity of the communication protocol puts strict requirements on various performances of the RF system. In the RF front-end module, the RF filter plays a vital role. It can filter out-of-band interference and combined noise to satisfy the RF system and Communication protocol requirements for signal-to-noise ratio.

RF filters are mainly used in wireless communication systems, for example, radio frequency front-ends of base stations, mobile phones, computers, satellite communications, radar, electronic countermeasure systems, etc. The main performance indicators of RF filters are insertion loss, out-of-band rejection, power capacity, linearity, device size and cost. Good filter performance can improve the data transmission rate, life and reliability of the communication system to a certain extent. Therefore, the design of high-performance and simplified filters for wireless communication systems is crucial.

(A) in Fig. 5 is the electrical symbol of the piezoelectric acoustic wave resonator, and (b) in Fig. 5 is its equivalent electrical model diagram. Without considering the loss term, the electrical model is simplified to Lm, Cm and C0 Resonant circuit composed. According to the resonance conditions, there are two resonance frequency points in the resonance circuit: one is fs when the impedance value of the resonance circuit reaches the minimum value, and fs is defined as the series resonance frequency point of the resonator; the other is when the impedance value of the resonance circuit reaches Fp at the maximum value, fp is defined as the parallel resonance frequency of the resonator. among them,

Also, fs is smaller than fp. At the same time, the effective electromechanical coupling coefficient kt ² eff of the resonator is defined, which can be expressed by fs and fp:

Figure 6 shows the relationship between resonator impedance and frequency. At a certain frequency, the greater the effective electromechanical coupling coefficient, the greater the frequency difference between fs and fp, that is, the farther away the two resonance frequencies are.

10 shows a schematic cross-sectional view of a structure 600 of a thin film bulk acoustic resonator, 611 is a semiconductor substrate material, 601 is an air cavity obtained by etching, and the bottom electrode 631 of the thin film bulk acoustic resonator is deposited on the semiconductor substrate 611 Above, 621 is the piezoelectric thin film material, 641 is the top electrode, and 651, 652, and 653 are the first layer mass load, the second layer mass load, and the third layer mass load of the film bulk acoustic resonator, respectively. The dotted framed area is the overlapping area of 601 air cavity, 631 upper electrode, 641 lower electrode, mass load, and 621 piezoelectric layer. This area is the effective resonance area.

FIG. 11 shows a schematic cross-sectional view of an acoustic wave piezoelectric resonator structure 700 of a solid-state assembly, and materials with high

acoustic impedance

771, 772, 773, 774 and low

acoustic impedance materials

761, 762, 763 are alternately stacked instead of FIG. 10. 601 air cavity, the thickness of the high acoustic impedance material and the low acoustic impedance material is a quarter of the wavelength of the acoustic wave, and the number of high acoustic impedance material and low acoustic impedance material stacked can be freely selected. 751, 752 and 753 are the first layer mass load, the second layer mass load and the third layer mass load of the solid-state assembly acoustic wave piezoelectric resonator, respectively.

The multi-channel filter is designed based on the bulk acoustic wave resonators of FIGS. 10 and 11, and the conventional multi-channel filter is obtained by cascading or paralleling multiple filters. As shown in FIG. 1, for a dual-channel filter 100 obtained by cascading filters, the first-stage ladder circuit network 101 and the second-stage ladder circuit network 102 are cascaded. In this example, the first stage Both the ladder circuit network 101 and the second-stage ladder circuit network 102 respectively include four series resonators and three parallel resonators. Such an approach will increase the out-of-band rejection of the multi-channel filter, but the insertion of the filter The damage is worse. As shown in FIG. 2, for a dual-channel filter 200 obtained by connecting filters in parallel, the first-stage ladder circuit network 201 and the second-stage ladder circuit network 202 are connected in parallel. In this example, the first-stage ladder circuit Both the type circuit network 201 and the second-stage ladder type circuit network 202 include four series resonators and three parallel resonators, respectively, such a method will obtain better insertion loss, but the out-of-band rejection is relatively poor.

In addition, for thin-film bulk acoustic resonators and solid-state bulk acoustic resonator piezoelectric devices, the common disadvantage of the above two design methods is that the multi-channel filter has several channels and it is necessary to design several dies. Both design and manufacturing have certain complexity.

Summary of the invention

In order to alleviate or solve at least one aspect of using the above problems in the prior art, the present invention is proposed.

The present invention proposes a multi-channel filter, including:

The series resonator branch has a plurality of series resonator units, and each series resonator unit has n series resonators connected in parallel, where n is a natural number not less than 2; and

The parallel resonator branch has multiple parallel resonator units. Each parallel resonator unit has n parallel resonators connected in series. One end of each parallel resonator unit is connected to the port of the corresponding series resonator unit, and the other end is suitable for In order to connect to the ground through the corresponding grounding inductance,

among them:

The i-th series resonator in all series resonator units constitutes the i-th series resonator. The resonators in the i-th series resonator all have a series-i mass load, i is a natural number and 1≤i≤n;

The i-th parallel resonator in all parallel resonator units constitutes the i-th group of parallel resonators, and the resonators in the i-th group of parallel resonators all have a parallel i-th mass load;

The i-th series resonator and the i-th parallel resonator together constitute the i-th frequency passband; and

In the series resonator unit, the mass loads of n series resonators are different from each other, and in the parallel resonator unit, the mass loads of n parallel resonators are different from each other.

Optionally, the series resonance frequency of the i-th series resonator is greater than the series resonance frequency of the i-th parallel resonator.

Optionally, the series resonance frequency of the i-th parallel resonator is greater than the series resonance frequency of the i+1th series resonator, where i≤n-1.

Optionally, the series resonance frequency of the i-th series resonator is greater than the parallel resonance frequency of the i-th parallel resonator.

Embodiments of the present invention also relate to a multi-channel filter, including:

The parallel resonator branch has multiple parallel resonator units, each parallel resonator unit has m parallel resonators connected in series, at least one parallel resonator unit has n parallel resonators, one end of each parallel resonator unit Connected to the port of the corresponding series resonator unit, the other end is suitable to be connected to the ground terminal through the corresponding grounding inductance, where m is a natural number less than n,

among them:

In the series resonator branch, series resonators having the same mass load constitute a series resonator group, and the series resonator branch has n series resonator groups;

In the parallel resonator branch, parallel resonators with the same mass load form a parallel resonator group, and the parallel resonator branch has n parallel resonator groups;

The series resonator group and the corresponding parallel resonator group respectively form a frequency pass band;

The load mass corresponding to each resonator group is different from each other.

Optionally, the resonance frequencies corresponding to the resonator groups are different from each other.

Optionally, in the above multi-channel filter, the thickness of the film layer based on the mass load is different and the mass load of the resonator is different. Further, the film thickness of different filters is a function of the frequency difference between the frequency pass bands and the bandwidth of the frequency pass band.

The passband bandwidth is determined by the thickness difference of the mass load film between the series resonator group and the corresponding parallel resonator group. The frequency bands that define the n-channel filter from high to low are 1, 2...i, i+1...n Pass band, where i≤n-1, the frequency difference between the i th pass band and the i+1 th pass band is determined by the thickness of the mass load film between the i th parallel resonator group and the i+1 th series resonator group Determined by the difference, in general, the resonator frequency of a mass-loaded resonator changes linearly with respect to the thickness of the mass-loaded film layer, which approximately meets the following relationship f _ML = f ₀ -T _ML *K, where f ₀ is without mass The resonant frequency of the load resonator, f _ML is the resonant frequency of the resonator after adding the mass load film thickness to T _ML , and K is the coefficient.

Optionally, the above multi-channel filter further includes: a node connected between two parallel resonators of one parallel resonator branch and a node between two parallel resonators of another parallel resonator branch Of inductance.

Optionally, in the above multi-channel filter, one parallel resonator branch and the other parallel resonator branch are grounded together.

Optionally, in the above multi-channel filter, the resonator is a bulk acoustic wave piezoelectric resonator with an air gap or a solid-state bulk acoustic wave piezoelectric resonator with a Bragg impedance reflection layer.

Optionally, in the above multi-channel filter, the multi-channel filter has an input/output port, and an impedance matching device is provided between the input/output port and the series resonator branch. Further, the impedance matching device is a passive device, and the passive device includes an inductor and a transmission line, and implementation methods of the passive device include bonding wires, chip integrated passive devices (IPD), package carrier integration, or Discrete devices.

Optionally, in the above multi-channel filter, a grounding inductance is provided at the input/output port of the multi-channel filter.

An embodiment of the present invention also relates to a multi-channel filter assembly, including at least two of the above multi-channel filters, wherein: the at least two multi-channel filters are connected in cascade, or the at least two multi-channel filters The devices are connected in parallel.

Embodiments of the present invention also relate to an electronic device having the above-mentioned multi-channel filter or the above-mentioned multi-channel filter component.

This patent proposes a circuit architecture of a multi-channel filter for devices such as thin-film bulk acoustic resonators and solid-state bulk acoustic piezoelectric resonators. This circuit architecture utilizes a mass load to implement a multi-channel filter on a single die In this way, the size of the device can be reduced by nearly twice, so that the miniaturization of the device can be better achieved; at the same time, the number of grounding inductors required for the design will be doubled, and the design and manufacturing are greatly reduced. The complexity greatly reduces the production cost.

BRIEF DESCRIPTION

The following description and drawings can better help to understand these and other features and advantages in the various embodiments disclosed in the present invention. The same reference numerals in the figures always denote the same parts, among which:

FIG. 1 is a schematic structural diagram of a dual-channel filter in the prior art, in which a dual-channel filter design is implemented by cascading two filters;

2 is a schematic structural diagram of a dual-channel filter in the prior art, in which a dual-channel filter design is implemented by connecting two filters in parallel;

3, 3-1, 3-2, 3-3, 3-4, and 3-5 are schematic diagrams of the structure of a dual-channel filter according to an exemplary embodiment of the present invention;

4 is a schematic structural diagram of a three-channel filter according to an exemplary embodiment of the present invention;

(A) in FIG. 5 is the electrical symbol of the piezoelectric acoustic wave resonator, and (b) in FIG. 5 is its equivalent electrical model diagram;

FIG. 6 is the impedance frequency characteristic curve of the resonator shown in FIG. 5;

Figure 7-1 shows the impedance frequency characteristic curve based on the resonator in Figure 3 operating at different frequencies;

In Fig. 7-2, (a) exemplarily shows a series resonator unit of a dual-channel filter with a single mass load, and (b) exemplarily shows a parallel resonator of a dual-channel filter with a single mass load unit;

In the exemplary graph of Figure 7-3, MagZ_Series corresponds to the impedance amplitude frequency characteristic curve of the 7-2(a) series resonator unit, MagZ_Shunt corresponds to the impedance amplitude frequency characteristic curve of the 7-2(b) parallel resonator unit, and S21 is The transmission characteristic curve of the dual-channel filter with a single die of mass load;

FIG. 8a schematically shows a frequency characteristic curve of input-output transmission based on the circuit shown in FIG. 3;

FIG. 8b schematically shows an enlargement of the frequency characteristic curve based on the input and output transmission of the circuit shown in FIG. 3;

FIG. 8c schematically shows a frequency characteristic curve based on the reflection coefficients of the input port and the output port of the circuit shown in FIG. 3;

FIG. 9a schematically shows an input-output transmission frequency characteristic curve based on the circuit shown in FIG. 4;

9b schematically shows an enlargement of the input-output transmission frequency characteristic curve based on the circuit shown in FIG. 4;

9c schematically shows a frequency characteristic curve based on the reflection coefficients of the input port and the output port of the circuit shown in FIG. 4;

10 is a schematic cross-sectional view of the structure of a thin film bulk acoustic resonator;

11 is a schematic cross-sectional view of the structure of a solid-state assembly acoustic wave piezoelectric resonator;

12 is a schematic diagram of an exemplary form of a series resonator unit in a series resonator branch according to an embodiment of the present invention.

detailed description

The technical solutions of the present invention will be further specifically described below through the embodiments and the accompanying drawings. In the description, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the drawings is intended to explain the general inventive concept of the present invention, and should not be construed as a limitation of the present invention.

FIG. 3 is a circuit diagram 300 of a multi-channel filter with a compound ladder structure. T1 is the input terminal of the dual-channel filter, and T2 is the output terminal of the dual-channel filter. The input and output terminals are ports for external signals connected to the dual-channel filter. Between the input terminal T1 and the output terminal T2, there are a series of first series resonators S11, S21, S31, S41 connected in series and connected in parallel in series, and second series resonators S10, S20, S30, S40 connected in series. The first series resonator and the second series resonator are connected in parallel, and then connected in series. The series first resonator has a series first series resonance frequency fss1 and a series first parallel resonance frequency fsp1, the series second resonator has a series second series resonance frequency fss2 and a series second parallel resonance frequency fsp2; and is located in a parallel path position 1. Parallel first resonators P10, P20, P30, and parallel second resonators P11, P21, P31 drawn from certain nodes on the series path; one end of the parallel first resonator P10 is connected to the series first resonator S11 And a node between the series first resonator S21; one end of the parallel first resonator P20 is connected to the node between the series first resonator S21 and the series first resonator S31; one end of the parallel first resonator P30 is connected to The node between the series first resonator S31 and the series first resonator S41. Parallel first resonator P10 and parallel second resonator P11 are connected in series, parallel first resonator P20 and parallel second resonator P21 are connected in series, parallel first resonator P30 and parallel second resonator P31 are connected in series . Parallel first resonators P10, P20, P30 have parallel first series resonance frequency fps1 and parallel first parallel resonance frequency fpp1, parallel second resonators P11, P21, P31 have parallel second series resonance frequency fps2 and parallel second parallel Resonant frequency fpp2.

The resonance frequency relationship of the first series resonator, the second series resonator, the first parallel resonator, and the second parallel resonator is shown in Figure 7-1, where fps2<fss2<fps1<fss1. In other words, in the example of FIG. 3, the resonance frequencies of the resonance frequencies of the series first resonator, the series second resonator, the parallel first resonator, and the parallel second resonator are as follows: series first resonator, A first resonator in parallel, a second resonator in series, and a second resonator in parallel.

As shown in Figure 7-2, (a) is a series resonator unit, including a series first resonator and a series second resonator. The second series resonator is equivalent to a capacitor in the resonance frequency band of the first series resonator, so that under the action of the second series resonator, the series first parallel resonance frequency of the series first resonator moves to a low frequency band, and the series first A series resonant frequency remains the same; in the same way, the series second parallel resonant frequency of the series second resonator moves to a lower frequency band, and the series second series resonant frequency does not change. (b) is a parallel resonator unit, including a parallel first resonator, a parallel second resonator and a second inductor. The parallel second resonator and the second inductance act on the parallel first resonator in combination, thereby affecting the parallel first series resonance frequency of the parallel first resonator, the parallel first parallel resonance frequency is unchanged; similarly, the parallel first resonator Combined with the second inductance, it acts on the parallel second resonator, thereby affecting the parallel second series resonance frequency of the parallel second resonator, and the parallel second parallel resonance frequency is unchanged. As shown in Figure 7-3, where MagZ_Series corresponds to the impedance amplitude-frequency characteristic curve of the 7-2(a) series resonator unit, MagZ_Shunt corresponds to the impedance amplitude-frequency characteristic curve of the 7-2(b) parallel resonator unit, and S21 is the mass The transmission characteristic curve of a dual-channel filter loaded with a single die. When the input signal frequency of the dual-channel filter is fps2, the impedance of the parallel resonator unit is a minimum value, and the signal is almost all short-circuited to ground, so the left transmission zero point of the low-frequency passband of the dual-channel filter appears at the fps2 point; When the input signal frequency of the dual-channel filter is near fpp2 and fss2, the impedance of the parallel resonator unit is the largest. At this time, the parallel branch is open, the signal does not flow to the ground, and the impedance of the series resonator unit is the smallest. When the series branch is short-circuited, the signal passes through the series branch almost without loss; when the input signal frequency of the dual-channel filter is fsp2, the impedance of the series resonator unit is the maximum value, and the impedance of the parallel resonator unit is relatively Smaller, the signal is almost all short-circuited to ground, and the right transmission zero of the low-frequency passband of the dual-channel filter appears at the fsp2 point; therefore, the input signals with frequencies of fpp2 and fss2 are screened out by the dual-channel filter. When the input signal frequency of the dual-channel filter is fps1, the impedance of the parallel resonator unit is a minimum value, and the signal is almost all short-circuited to ground, so the left transmission zero point of the high-frequency passband of the dual-channel filter appears at the fps1 point ; When the input signal frequency of the dual-channel filter is near fpp1 and fss1, the impedance of the parallel resonator unit is the largest. At this time, the parallel branch is open, the signal will not flow to the ground, and the impedance of the series resonator unit is the smallest. At this time, the series branch is short-circuited, and the signal passes through the series branch almost without loss; when the input signal frequency of the dual-channel filter is fsp1, the impedance of the series resonator unit is the maximum value, and the impedance of the parallel resonator unit Relatively small, the signal is almost completely short-circuited to ground, and the right transmission zero of the low-frequency passband of the dual-channel filter appears at the point fsp1; therefore, the input signals with frequencies at fpp1 and fss1 are screened out by the dual-channel filter.

In addition, auxiliary inductors L1 and L2 are added to connect the series resonator to the input and output terminals of the filter, and auxiliary inductors L5, L6, and L7 are added to connect the parallel resonator to the ground. The auxiliary inductance may be a bonding wire used for connecting the chip and the package carrier, or may be a metal conductor used for flip-chip welding the chip on the package carrier, such as a copper pillar, a solder ball, and the like. The auxiliary inductors L1, L2, L5, L6, and L7 may also be referred to as second inductances, and the inductance of the second inductor is generally in the range of 0.1 nH to 0.8 nH.

In order for the filter to achieve better characteristics in the passband range, a first inductor L3 for impedance matching is added near the input terminal T1, and a third inductor for impedance matching is added near the output terminal T2 An inductor L4, the inductance values of the first inductor L3 and the first inductor L4 are in the range of 1nH-20nH, and further, in the range of 1nH-10nH. That is, the inductance value of the first inductor is larger than the inductance value of the second inductor. Among them, the impedance matching device for user impedance matching is not limited to inductors, it can also include other passive devices, such as capacitors, transmission lines, etc., and the implementation of passive devices includes but is not limited to bonding wires, chip integrated passive devices ( IPD), package carrier integration, discrete devices, etc.

In the present invention, according to an embodiment of the present invention, the first inductor and the second inductor may be implemented on a packaging substrate. According to an embodiment of the present invention, the first inductor and the second inductor may also be discrete inductor devices, which are provided outside the chip and integrated in a package carrier, and the package carrier includes the chip.

According to an embodiment of the present invention, the second inductor includes a bonding wire for connecting the chip and the package carrier, or includes a metal conductor for flip-chip bonding the chip on the package carrier.

FIG. 8 is a graph of the amplitude-frequency response of the insertion loss and return loss of the multi-channel filter 300, where FIG. 8a is the insertion loss curve of the filter in a wide frequency band, and FIG. 8b is the insertion loss curve of the filter into the passband. In 8c, S11 is the return loss curve of the filter input port, and S22 is the return loss curve of the filter output port. For bulk acoustic wave piezoelectric resonators (FBAR) with air gaps or solid-state body acoustic wave piezoelectric resonators (SMR) devices with Bragg impedance reflection layers, the traditional design method for dual-channel filters is to use two filter stages Connected or connected in parallel, the common shortcoming of the two methods is that the multi-channel filter has several channels and it is necessary to design several dies. Both the design and the manufacturing have certain complexity. Based on the filter 300 of an embodiment of the present invention, for FBAR and SMR devices, a new method for designing a multi-channel filter is proposed. This circuit architecture can use a mass load to implement a multi-channel filter with a single die Design greatly reduces the complexity of design and manufacturing, and the size of the device is nearly doubled, which can better achieve the miniaturization of the device.

Figure 3-1 is an embodiment based on the present invention. One or more parallel branches in the dual-channel filter can be composed of a single parallel first resonator or a single parallel second resonator, in this embodiment, the series first resonators S10, S20, S30, S40 and the parallel first resonance P10 and P20 form a high-band filter passband, and series second resonators S11, S21, S31, S41 and P11, P21, P31 form a low-band filter passband. In general, the smaller the number of filter series resonators, the smaller the insertion loss and the worse the out-of-band rejection, so a similar architecture can be applied to design dual-channel filters with specific specifications, while also increasing to a certain extent Design flexibility.

Figure 3-2 is another embodiment based on the present invention. In this embodiment, series first resonators S10, S20, S30, S40 and parallel first resonators P10, P20, P30 form a high-band filter passband, and series second resonators S11, S21, S31, S41, and P11, P21 and P31 form the low-band filter passband. In the two-channel filter, an inductance L8 is added between the connecting nodes of the parallel first resonator and the parallel second resonator of any two parallel branches. When the high-band filter works, the two branches connected by the inductor L8 are combined. Ground, so that the near-stopband rejection of the filter can be changed as required by the design specifications.

Figure 3-3 is another embodiment based on the present invention. In this embodiment, series first resonators S10, S20, S30, S40 and parallel first resonators P10, P20, P30 form a high-band filter passband, and series second resonators S11, S21, S31, S41, and P11, P21 and P31 form the low-band filter passband. In any two-channel filter, any two parallel branches are connected between the ground terminal nodes. The high-band filter and the low-band filter can realize the ground connection between the two parallel branches at the same time.

Figure 3-4 is another embodiment based on the present invention. This embodiment may be composed of two dual-channel filter dies working in different frequency bands to realize a four-channel filter.

Figures 3-5 are another embodiment based on the present invention. This embodiment cascades two dual-channel filters (die1, die2). When two dies work in different frequency bands, a four-channel filter design is realized; when two dies work in the same frequency band, ultra-high Dual-channel filter design with out-of-band rejection.

FIG. 4 is a schematic diagram of another embodiment 400 based on the present invention. T1 is the input terminal of the filter, and T2 is the output terminal of the filter. The input and output terminals are ports for external signals connected to the dual-channel filter. Between the input terminal T1 and the output terminal T2, there is a series of series-connected first resonators S12, S22, S32, S42 connected in series at the position of the series path, series-connected second resonators S11, S21, S31, S41, connected in series The third resonators S10, S20, S30, and S40, the first series resonator, the second series resonator, and the third series resonator are connected in parallel, and then connected in series. The series first resonator has a series first series resonance frequency fss1 and a series first parallel resonance frequency fsp1, the series second resonator has a series second series resonance frequency fss2 and a series second parallel resonance frequency fsp2, and the series third resonator has Series third series resonance frequency fss3 and series third parallel resonance frequency fsp3; and parallel first resonators P10, P20, P30 located at the position of the parallel path and drawn from certain nodes on the series path, parallel second resonator P11 , P21, P31, and the parallel third resonators P12, P22, P32; one end of the parallel first resonator P10 is connected to the node between the series first resonator S12 and the series first resonator S22; the parallel first resonator One end of P20 is connected to the node between the series first resonator S22 and the first series resonator S32; one end of the parallel first resonator P30 is connected to the node between the first series resonator S32 and the first series resonator S42 . Parallel first resonator P10, parallel second resonator P11 and parallel third resonator P12 are connected in series, parallel first resonator P20, parallel second resonator P21 and parallel third resonator P22 are connected in series, parallel A resonator P30, a parallel second resonator P31 and a parallel third resonator P32 are connected in series. Parallel first resonators P10, P20, P30 have parallel first series resonance frequency fps1 and parallel first parallel resonance frequency fpp1, parallel second resonators P11, P21, P31 have parallel second series resonance frequency fps2 and parallel second parallel Resonance frequency fpp2, parallel third resonators P12, P22, P32 have parallel third series resonance frequency fps3 and parallel third parallel resonance frequency fpp3, series first resonator, series second resonator, series third resonator, parallel The resonance frequency relationship of the first resonator, the parallel second resonator, and the parallel third resonator is fps3<fss3<fps2<fss2<fps1<fss1.

Based on the above, the present invention proposes a multi-channel filter, including:

among them:

It should be specifically pointed out that in the present invention, although the expression "i" is used for the expression of the i-th series resonator, the "piece" includes not only the case of one series resonator in practice, but also a plurality of series resonators. Equivalent to the case of a series resonator. Specifically, the series resonator located above in (a) of FIG. 7-2 may be a single series resonator S10 in FIG. 3 or two series resonators shown in FIG. 12 (of course There may be more) corresponding equivalent series resonators. A similar understanding is made for the expression "a" in the i-th parallel resonator. These are all within the protection scope of the present invention.

Correspondingly, the present invention also proposes a multi-channel filter, including:

among them:

The series resonator group and the corresponding parallel resonator group respectively form a frequency pass band; and

The mass loads corresponding to the respective resonator groups are different from each other.

In addition, auxiliary inductors L1 and L2 are added to connect the series resonator to the input and output terminals of the filter, and auxiliary inductors L5, L6, and L7 are added to connect the parallel resonator to the ground. The auxiliary inductance may be a bonding wire used for connecting the chip and the package carrier, or may be a metal conductor used for flip-chip welding the chip on the package carrier, such as a copper pillar, a solder ball, and the like. The auxiliary inductors L1, L2, L5, L6, and L7 may also be called second inductances, and the inductance of the second inductor is generally in the range of 0.1 nH to 0.8 nH. In order for the filter to achieve better characteristics in the passband range, a first inductor L3 for impedance matching is added near the input terminal T1, and a third inductor for impedance matching is added near the output terminal T2 An inductor L4, the inductance values of the first inductor L3 and the first inductor L4 are in the range of 1nH-20nH. That is, the inductance value of the first inductor is larger than the inductance value of the second inductor. Among them, the impedance matching device for user impedance matching is not limited to inductors, it can also include other passive devices, such as capacitors, transmission lines, etc., and the implementation of passive devices includes but is not limited to bonding wires, chip integrated passive devices ( IPD), package carrier integration, discrete devices, etc.

9 is a graph of the amplitude-frequency response of the insertion loss and return loss of the multi-channel filter 400, where FIG. 9a is the insertion loss curve of the filter in a wide frequency band, and FIG. 9b is the insertion loss curve of the filter into the passband. In 9c, S11 is the return loss curve of the filter input port, and S22 is the return loss curve of the filter output port.

In addition, the realization of more channel filters based on this invention can be realized by adding parallel branches on the series path and series branches on the parallel path. The n-channel filter is composed of a first series resonator, a second series resonator... ...The nth series resonator is composed of the first parallel resonator, the second parallel resonator...the nth parallel resonator and will not be repeated here.

In addition, “approximately”, “close to”, “approximately” and the like appearing in the present invention mean within the error range recognized by those skilled in the art.

Embodiments of the present invention also relate to an electronic device, including the filter described above. It should be noted that the electronic devices here include but are not limited to intermediate products such as radio frequency front-ends, filter amplification modules, and terminal products such as mobile phones, WIFI, and drones.

Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that these embodiments can be changed without departing from the principle and spirit of the present invention. The appended claims and their equivalents are limited.

Claims

A multi-channel filter, including:

The series resonator branch has a plurality of series resonator units, and each series resonator unit has n series resonators connected in parallel, where n is a natural number not less than 2; and

The parallel resonator branch has multiple parallel resonator units. Each parallel resonator unit has n parallel resonators connected in series. One end of each parallel resonator unit is connected to the port of the corresponding series resonator unit, and the other end is suitable for In order to connect to the ground through the corresponding grounding inductance,

among them:

The i-th series resonator in all series resonator units constitutes the i-th series resonator. The resonators in the i-th series resonator all have a series-i mass load, i is a natural number and 1≤i≤n;

The i-th parallel resonator in all parallel resonator units constitutes the i-th group of parallel resonators, and the resonators in the i-th group of parallel resonators all have a parallel i-th mass load;

The i-th series resonator and the i-th parallel resonator together constitute the i-th frequency passband; and

In the series resonator unit, the mass loads of n series resonators are different from each other, and in the parallel resonator unit, the mass loads of n parallel resonators are different from each other.
The multi-channel filter according to claim 1, wherein:

The series resonance frequency of the i-th series resonator is greater than the series resonance frequency of the i-th parallel resonator.
The multi-channel filter according to claim 2, wherein:

The series resonance frequency of the i-th parallel resonator is greater than the series resonance frequency of the i+1th series resonator, where i≤n-1.
The multi-channel filter according to claim 2 or 3, wherein:

The series resonance frequency of the i-th series resonator is greater than the parallel resonance frequency of the i-th parallel resonator.
A multi-channel filter, including:

The series resonator branch has a plurality of series resonator units, and each series resonator unit has n series resonators connected in parallel, where n is a natural number not less than 2; and

The parallel resonator branch has multiple parallel resonator units, each parallel resonator unit has m parallel resonators connected in series, at least one parallel resonator unit has n parallel resonators, one end of each parallel resonator unit Connected to the port of the corresponding series resonator unit, the other end is adapted to be connected to the ground terminal through a corresponding grounding inductance, where m is a natural number less than n, where:

In the series resonator branch, series resonators having the same mass load constitute a series resonator group, and the series resonator branch has n series resonator groups;

In the parallel resonator branch, parallel resonators with the same mass load form a parallel resonator group, and the parallel resonator branch has n parallel resonator groups;

The series resonator group and the corresponding parallel resonator group respectively form a frequency pass band;

The mass loads corresponding to the respective resonator groups are different from each other.
The multi-channel filter according to claim 1 or 5, wherein:

The resonance frequency corresponding to each resonator group is different from each other.
The multi-channel filter according to claim 1 or 5, wherein:

The thickness of the film layer based on the mass load is different and the mass load of the resonator is different.
The multi-channel filter according to claim 6, wherein:

The film thickness of different filters is a function of the frequency difference between the frequency passbands and the bandwidth of the frequency passband.
The multi-channel filter according to claim 1 or 5, further comprising:

The inductance between a node connected between two parallel resonators of one parallel resonator branch and a node between two parallel resonators of another parallel resonator branch.
The multi-channel filter according to claim 1 or 5, wherein:

One parallel resonator branch and the other parallel resonator branch are grounded together.
The multi-channel filter according to claim 1 or 5, wherein:

The resonator is a bulk acoustic wave piezoelectric resonator with an air gap or a solid-state bulk acoustic wave piezoelectric resonator with a Bragg impedance reflection layer.
The multi-channel filter according to claim 1 or 5, wherein:

The multi-channel filter has an input/output port, and an impedance matching device is provided between the input/output port and the series resonator branch.
The multi-channel filter according to claim 12, wherein:

The impedance matching device is a passive device, and the passive device includes an inductor and a transmission line. The implementation of the passive device includes a bonding wire, a chip integrated passive device (IPD), a package carrier integrated, or a discrete device.
The multi-channel filter according to claim 1 or 5, wherein:

A grounding inductance is provided at the input/output port of the multi-channel filter.
A multi-channel filter assembly comprising at least two multi-channel filters according to any one of claims 1-10, wherein: the at least two multi-channel filters are connected in cascade, or the at least two A multi-channel filter is connected in parallel.
An electronic device having the multi-channel filter according to any one of claims 1-14 or the multi-channel filter component according to claim 15.