CN218772031U

CN218772031U - Hybrid acoustic filter and filter

Info

Publication number: CN218772031U
Application number: CN202223015321.8U
Authority: CN
Inventors: 高安明; 姜伟
Original assignee: Zhejiang Xingyao Semiconductor Co ltd
Current assignee: Zhejiang Xingyao Semiconductor Co ltd
Priority date: 2022-11-11
Filing date: 2022-11-11
Publication date: 2023-03-28
Anticipated expiration: 2032-11-11

Abstract

The utility model provides a mix acoustic filter and wave filter, include: an acoustic resonant network and an LC matching network; the LC matching network is coupled on both sides of the acoustic resonant network. The utility model discloses multiple type LC matching network is coupled in acoustics resonance network both sides to the high performance band pass filter who has that the passband bandwidth is big, roll-off characteristic is good, flat and outband restrain effectual equal electrical performance in the passband.

Description

Hybrid acoustic filter and filter

Technical Field

The utility model relates to an electronic components field specifically, relates to a mix acoustic filter and wave filter.

Background

With the rapid development of wireless communication technology, the rf filter becomes one of the key devices of the wireless communication device due to the selection or filtering function for the rf signal of a specific frequency band, and particularly, the acoustic filter has the characteristics of miniaturization, high performance and compatibility with the IC process, so that the characteristics suitable for mass production are in accordance with the high requirements and standards of the wireless communication device for its internal devices.

In the prior art, a filter is mainly formed by connecting a plurality of acoustic resonators in series and parallel, and a ladder type filter and a lattice type filter are typical. The ladder filter structure shown in fig. 1 is composed of a plurality of series resonators Rs and a plurality of parallel resonators Rp. In the design process, the out-of-band rejection effect is good when the number of resonators is large, but the in-band ripple is obvious and the device size is increased, and the out-of-band rejection effect is poor when the number of resonators is small, so that the design difficulty is greatly increased due to the fact that the number of resonators needs to be balanced in many aspects. In the process, two types of acoustic resonators (Rs and Rp) are often required to be processed on the wafer, which undoubtedly increases the process difficulty.

SUMMERY OF THE UTILITY MODEL

To the defect among the prior art, the utility model aims at providing a mix acoustic filter and wave filter.

According to the utility model provides a pair of hybrid acoustic filter, include: an acoustic resonant network 1 and an LC matching network 2;

the LC matching network 2 is coupled on both sides of the acoustic resonant network 1.

Preferably, the acoustic resonant network 1 comprises: an acoustic resonator R01 and an inductance L01;

the acoustic resonator R01 is connected with the inductor L01 in parallel;

the acoustic resonant network 1 has a center frequency F0 and two cut-off frequencies F1, F2, the two cut-off frequencies F1, F2 being located on either side of the center frequency F0.

Preferably, the LC matching network 2 comprises: an LC tank and an inductor;

one end of the inductor is connected with an input/output port, the other end of the inductor is connected with the acoustic resonance network 1, one end of the LC tank is connected between the acoustic resonance network 1 and the inductor, and the other end of the LC tank is grounded.

Preferably, the LC matching network 2 comprises: an LC tank and a capacitor;

one end of the capacitor is connected with an input/output port, the other end of the capacitor is connected with the acoustic resonance network 1, one end of the LC tank is connected between the acoustic resonance network 1 and the capacitor, and the other end of the LC tank is grounded.

Preferably, the LC tank comprises a capacitance and an inductance in parallel.

Preferably, the LC matching network 2 includes: an inductor and a capacitor;

one end of the capacitor is connected with an input/output port, the other end of the capacitor is connected with the acoustic resonance network 1, one end of the inductor is connected between the acoustic resonance network 1 and the capacitor, and the other end of the inductor is grounded.

Preferably, the LC matching networks 2 at both ends of the acoustic resonant network 1 are identical or different in structure.

Preferably, the inductor L01 is connected in parallel with the acoustic resonator R01 by means of surface mounting, integrated passive devices, or patches on a package substrate.

Preferably, the LC matching network 2 is coupled to the acoustic resonant network 1 by means of surface mounting, integrated passive devices or patches on a package substrate.

According to the utility model provides a pair of wave filter, including one or two the hybrid acoustic wave filter, two establish ties each other between the hybrid acoustic wave filter.

Compared with the prior art, the utility model discloses following beneficial effect has:

1. the utility model discloses multiple type LC matching network is coupled in acoustics resonance network both sides to the high performance band pass filter who has that the passband bandwidth is big, roll-off characteristic is good, flat and outband restrain effectual equal electrical performance in the passband.

2. For traditional wave filter, the utility model discloses at most only need two acoustics syntonizers, simplified band pass filter's circuit structure greatly to manufacturing cost has been reduced.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of a conventional ladder filter structure;

fig. 2 is a schematic structural diagram of the acoustic resonant network of the present invention;

FIG. 3 is a schematic diagram of the frequency response of an acoustic resonant network;

fig. 4 is a schematic structural diagram of an LC matching network according to the present invention;

fig. 5 is a schematic structural diagram of an LC matching network according to the present invention;

fig. 6 is a schematic structural diagram of an LC matching network according to the present invention;

fig. 7 is a schematic structural diagram of a hybrid acoustic filter according to embodiment 1 of the present invention;

fig. 8 is a schematic frequency response diagram of a hybrid acoustic filter according to embodiment 1 of the present invention;

FIG. 9 is an enlarged view of a portion of FIG. 8;

fig. 10 is a schematic structural diagram of a hybrid acoustic filter according to embodiment 2 of the present invention;

fig. 11 is a schematic structural diagram of a hybrid acoustic filter according to embodiment 3 of the present invention;

fig. 12 is a schematic structural diagram of a filter according to the present invention;

fig. 13 is a schematic structural diagram of a filter according to the present invention.

Detailed Description

The present invention will be described in detail with reference to the following embodiments. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that various changes and modifications can be made by one skilled in the art without departing from the spirit of the invention. These all belong to the protection scope of the present invention.

The utility model provides a pair of hybrid acoustic filter, include: an acoustic resonant network and a matching network. As shown in fig. 2, the acoustic resonant network is formed by connecting an acoustic resonator R01 and an inductor L01 in parallel. The acoustic resonator may be a surface acoustic wave resonator, a thin film bulk acoustic resonator, a solid state mount resonator, the like, or any combination thereof. The inductor may be connected in parallel with the acoustic resonator by surface mount technology, integrated passive device technology, or by a patch on a package substrate. As shown in fig. 3, the arrangement of the resonator in parallel with the inductor makes the acoustic resonant network a filter with 1 center frequency (F0) and 2 cut-off frequencies (F1 & F2), especially F1, F2 on both sides of F0, as will be understood with particular reference to the drawing of its frequency response. However, as can be seen from the frequency response curve of fig. 3, the curve cut between the frequencies F1, F2 is relatively sharp and does not form a passband, which does not meet the basic requirements of a high performance filter. Therefore, the present application also provides various LC matching networks on both sides of the acoustic resonant network.

The LC matching network is composed of a plurality of capacitors C and inductors L which are connected in series and in parallel, and three structures are provided in the application.

The structure I is as follows:

as shown in fig. 4, the resonant tank consists of an LC tank and an inductor, wherein a port is used as a signal input end or an output end or is connected with other networks, and b port is connected with an acoustic resonant network. The LC tank is a capacitor and inductor structure connected in parallel, one end of the LC tank is connected between the inductor and the capacitor at the b port, and the other end of the LC tank is grounded. The structure is the most flexible way of adjustment, the best overall electrical performance, and is therefore set forth as the most preferred embodiment.

The structure II is as follows:

as shown in fig. 5, consists of an LC tank and a capacitor. And on the basis of the first structure, the inductance between the ports a and b is replaced by the capacitance, and the connection mode is the same as that of the first structure. The structure has the advantage that the cost of the subsequent hybrid acoustic filter can be reduced by replacing the capacitance with the inductance as much as possible.

The structure is three:

as shown in fig. 6, the LC tank consists of an inductor and a capacitor, and the capacitor of the LC tank is removed on the basis of the second structure. One end of the inductor is connected between the capacitor and the port b, and the other end of the inductor is grounded. The structure has the advantage that the out-of-band rejection effect in the range below the cut-off frequency F1 of the subsequent hybrid acoustic filter can be improved.

EXAMPLE 1 (preferred embodiment)

As shown in fig. 7, a hybrid acoustic filter includes: an acoustic resonant network 1 and an LC matching network 2. The two LC matching networks 2 are both connected with the acoustic resonant network 1 through the b-port, and the other end of the two LC matching networks is used as a radio frequency signal input end or an output end (in and out can be exchanged). The LC matching network 2 may be coupled to the acoustic resonant network 1 by surface mount technology, integrated passive device technology, or patch on package substrate technology, among others.

The frequency response curve of the embodiment shows that a filter with excellent performance is obtained after the two ends of the acoustic resonant network 1 are coupled with the LC matching network 2. In the frequency response curve of fig. 8, it can be found that there is a good out-of-band suppression effect in the frequency ranges smaller than the cutoff frequency F1 and larger than the cutoff frequency F2. Further, the enlarged partial frequency response diagram shown in fig. 9 is a partially enlarged curve shape in the frequency response box of fig. 8, and the diagram visually shows that after the acoustic resonant network is coupled to the LC matching network, a passband with a larger bandwidth is formed between F1 and F2, and the passband Bandwidth (BW) is as high as 165MHz; the waveform in the passband is flat; the curves on both sides of the pass band and close to the cut-off frequencies F1, F2 exhibit good roll-off characteristics. The above characteristics all reflect the excellent electrical performance of the high-performance hybrid acoustic filter. The frequency response curve is a test result obtained by setting the capacitance and the inductance as certain parameter values, and the parameters of each electrical element (the capacitance and the inductance) can be flexibly set in practical application to obtain the high-performance filter meeting the requirements.

Example 2

As shown in fig. 10, a hybrid acoustic filter includes: the device comprises an acoustic resonant network 1 and an LC matching network 2, wherein the b-port of the two LC matching networks 2 is electrically connected with the acoustic resonant network 1, and the other end of the two LC matching networks 2 is used as a radio frequency signal input end or output end (in and out can be exchanged). The LC matching network 2 may be coupled to the acoustic resonant network 1 by surface mount technology, integrated passive device technology, or chip on package substrate, which may reduce the cost.

Example 3

As shown in fig. 11, a hybrid acoustic filter includes: the device comprises an acoustic resonance network 1 and an LC matching network 2, wherein both LC matching networks 3 are b-ports which are electrically connected with the acoustic resonance network 1, and the other ends of the LC matching networks are used as radio-frequency signal input ends or output ends (in and out can be exchanged). The LC matching network 3 may be coupled to the acoustic resonant network 1 by surface mount technology, integrated passive device technology, or patch on package substrate technology, among others.

Example 4

This embodiment provides a filter including one or two hybrid acoustic filters as shown in embodiment 1, embodiment 2 and/or embodiment 3, the two hybrid acoustic filters being connected in series with each other. For example, two of the

embodiments

1, 2 and 3 are connected in series, and any two of the

embodiments

1, 2 and 3 are connected in series. Fig. 12 shows two hybrid acoustic filters of embodiment 1 connected in series, and fig. 13 shows two hybrid acoustic filters of embodiment 1 and embodiment 2 connected in series. The better electrical performance compared with the embodiment 1 can be realized, but the circuit complexity is high, and the method is still used as an extension case of the embodiment 1.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of the specific embodiments of the invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by those skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims

1. A hybrid acoustic filter, comprising: an acoustic resonant network (1) and an LC matching network (2);

the LC matching network (2) is coupled on two sides of the acoustic resonance network (1);

the acoustic resonant network (1) comprises: an acoustic resonator R01 and an inductance L01;

the acoustic resonator R01 is connected with the inductor L01 in parallel;

the acoustic resonant network (1) has a center frequency F0 and two cut-off frequencies F1, F2, the two cut-off frequencies F1, F2 being located on either side of the center frequency F0.

2. The hybrid acoustic filter of claim 1, wherein the LC matching network (2) comprises: an LC tank and an inductor;

one end of the inductor is connected with an input/output port, the other end of the inductor is connected with the acoustic resonance network (1), one end of the LC tank is connected between the acoustic resonance network (1) and the inductor, and the other end of the LC tank is grounded.

3. The hybrid acoustic filter of claim 1, wherein the LC matching network (2) comprises: an LC tank and a capacitor;

one end of the capacitor is connected with an input/output port, the other end of the capacitor is connected with the acoustic resonance network (1), one end of the LC tank is connected between the acoustic resonance network (1) and the capacitor, and the other end of the LC tank is grounded.

4. A hybrid acoustic filter according to claim 2 or 3, wherein the LC tank comprises a capacitance and an inductance in parallel.

5. The hybrid acoustic filter according to claim 1, wherein the LC matching network (2) comprises: an inductor and a capacitor;

one end of the capacitor is connected with an input/output port, the other end of the capacitor is connected with the acoustic resonance network (1), one end of the inductor is connected between the acoustic resonance network (1) and the capacitor, and the other end of the inductor is grounded.

6. A hybrid acoustic filter according to claim 1, characterized in that the LC matching networks (2) at both ends of the acoustic resonant network (1) are structurally identical or different.

7. The hybrid acoustic filter of claim 1, wherein the inductor L01 is connected in parallel with the acoustic resonator R01 by means of surface mounting, integrated passive devices, or patches on a package substrate.

8. The hybrid acoustic filter according to claim 1, characterized in that the LC matching network (2) is coupled to the acoustic resonant network (1) by means of surface mounting, integrated passive components or patches on a package substrate.

9. A filter comprising one or two hybrid acoustic filters according to any one of claims 1 to 8, the two hybrid acoustic filters being connected in series with each other.