CN113054380A

CN113054380A - Communication device and filter thereof

Info

Publication number: CN113054380A
Application number: CN201911383529.5A
Authority: CN
Inventors: 李华; 蔡永宏; 刘学鑫; 贺从虎
Original assignee: Shenzhen Tatfook Technology Co Ltd
Current assignee: Shenzhen Tatfook Technology Co Ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2021-06-29

Abstract

The application discloses a communication system and a filter thereof. The filter includes: the filter comprises a shell, a first filtering branch and a second filtering branch. A housing having a first direction and a second direction perpendicular to the first direction; the first filtering branch is arranged on the shell and consists of nine filtering cavities which are sequentially coupled, and the nine filtering cavities of the first filtering branch comprise two cross-coupling zeros; the second filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering branch comprise two cross-coupling zeros; the projection parts of the first filtering branch and the second filtering branch in the first direction are overlapped. Through the mode, the product complexity can be reduced, the stability of the filter is improved, and the filter can be reduced due to the close arrangement.

Description

Communication device and filter thereof

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication system and a filter thereof.

Background

In a mobile communication system, a desired signal is modulated to form a modulated signal, the modulated signal is carried on a high-frequency carrier signal, the modulated signal is transmitted to the air through a transmitting antenna, the signal in the air is received through a receiving antenna, and the signal received by the receiving antenna does not include the desired signal but also includes harmonics and noise signals of other frequencies. The signal received by the receiving antenna needs to be filtered by a filter to remove unnecessary harmonic and noise signals. Therefore, the designed filter must accurately control its upper and lower limit frequencies. And should also consider maintaining high isolation between the passbands of the channels if both transmit and receive channels are present.

The inventor of this application discovers in long-term research and development work that the distance between a plurality of filtering chambeies is unequal, and the volume of wave filter is increased in the space of the cavity of unable make full use of wave filter to the decentralized design, and in addition, present wave filter includes a plurality of filtering branch roads, and the output and the input of every filtering branch road all need set up the tap, occupy the space of wave filter, lead to the bulky of wave filter.

Disclosure of Invention

The application provides a filter to solve the technical problems of the filter.

To solve the above problem, an embodiment of the present application provides a filter, including: the filter comprises a shell, a first filtering branch and a second filtering branch. A housing having a first direction and a second direction perpendicular to the first direction; the first filtering branch is arranged on the shell and consists of nine filtering cavities which are sequentially coupled, and the nine filtering cavities of the first filtering branch comprise two cross-coupling zeros; the second filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering branch comprise two cross-coupling zeros; the projection parts of the first filtering branch and the second filtering branch in the first direction are overlapped.

The product complexity can be reduced, the stability of the filter is improved, and the compact arrangement can reduce the size of the filter.

Preferably, the first filter cavity, the second filter cavity, the third filter cavity and the fourth filter cavity of the first filter branch are in a row and are sequentially arranged along the second direction; a fifth filter cavity of the first filter branch is far away from the second filter branch relative to the fourth filter cavity, and an included angle between a connecting line of the center of the fifth filter cavity and the center of the fourth filter cavity of the first filter branch and a connecting line of the center of the third filter cavity and the center of the fourth filter cavity is an acute angle;

the fifth filtering cavities and the eighth filtering cavities of the first filtering branch are in a row and are sequentially arranged along the second direction; the sixth filtering cavities and the seventh filtering cavities of the first filtering branch are in a row and are sequentially arranged along the second direction; the ninth filtering cavity of the first filtering branch is considered towards the second filtering branch relative to the eighth filtering cavity, the ninth filtering cavity and the seventh filtering cavity of the first filtering branch are arranged adjacently, and the ninth filtering cavity, the eighth filtering cavity and the seventh filtering cavity are arranged in a triangular mode.

The row cavities are arranged in sequence, so that the space of the cavities is fully utilized, the volume of the cavities is reduced, debugging is facilitated, and the production cost is reduced.

Preferably, the first filter cavity, the second filter cavity, the third filter cavity, the fifth filter cavity and the eighth filter cavity of the second filter branch are in a row and are sequentially arranged along the second direction; the fourth filtering cavity, the sixth filtering cavity and the seventh filtering cavity of the second filtering branch are in a row and are sequentially arranged along the second direction; a fourth filter cavity of the second filter branch is respectively adjacent to the third filter cavity and the fifth filter cavity; a sixth filter cavity of the second filter branch is respectively adjacent to the fifth filter cavity and the eighth filter cavity; and a seventh filtering cavity and an eighth filtering cavity of the second filtering branch circuit are arranged adjacently.

Preferably, the fifth filter cavity and the eighth filter cavity of the first filter branch and the sixth filter cavity and the eighth filter cavity of the first filter branch are respectively cross-coupled to form two cross-coupling zeros of the first filter branch; and the third filtering cavity and the fifth filtering cavity of the second filtering branch circuit and the sixth filtering cavity and the eighth filtering cavity of the second filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the second filtering branch circuit.

The inductive cross coupling and the capacitive cross coupling can achieve high isolation, the out-of-band rejection performance is greatly improved, the isolation is high, and the radio frequency performance index of the filter is improved. Preferably, the filter further includes a third filtering branch and a fourth filtering branch, the third filtering branch and the second filtering branch are divided into three rows arranged in sequence along the first direction, and the fourth filtering branch is divided into two rows arranged in sequence along the first direction.

Preferably, the first filter cavity, the fourth filter cavity, the sixth filter cavity, the seventh filter cavity and the eighth filter cavity of the third filter branch are in a row and are sequentially arranged along the second direction; the second filtering cavity, the fourth filtering cavity and the fifth filtering cavity of the third filtering branch circuit, and the fourth filtering cavity, the sixth filtering cavity and the seventh filtering cavity of the second filtering branch circuit are in a row and are sequentially arranged along the second direction.

Preferably, the first filter cavity, the second filter cavity, the third filter cavity, the fourth filter cavity, the fifth filter cavity, the eighth filter cavity and the ninth filter cavity of the fourth filter branch are in a row and are sequentially arranged along the second direction; the sixth filtering cavities and the seventh filtering cavities of the fourth filtering branch are in a row and are sequentially arranged along the second direction; a sixth filter cavity of the fourth filter branch is respectively adjacent to the fifth filter cavity, the seventh filter cavity, the eighth filter cavity and the sixth filter cavity of the first filter branch;

the first filter cavity of the fourth filter branch is arranged adjacent to the first filter cavity of the third filter branch, and the second filter cavity of the fourth filter branch is arranged adjacent to the fourth filter cavity of the third filter branch; the eighth filter cavity of the third filter branch is respectively adjacent to the seventh filter cavity and the sixth filter cavity of the second filter branch and the fourth filter cavity of the fourth filter branch;

the fifth filtering cavity and the eighth filtering cavity of the third filtering branch circuit and the sixth filtering cavity and the eighth filtering cavity of the third filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the third filtering branch circuit; and the first filtering cavity and the third filtering cavity of the fourth filtering branch circuit and the fourth filtering cavity and the sixth filtering cavity of the fourth filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the fourth filtering branch circuit.

The inductive cross coupling and the capacitive cross coupling can achieve high isolation, the out-of-band rejection performance is greatly improved, the isolation is high, and the radio frequency performance index of the filter is improved. Preferably, the filter further includes a fifth filtering branch, a sixth filtering branch, a seventh filtering branch, an eighth filtering branch, a ninth filtering branch, a tenth filtering branch, an eleventh filtering branch, and a twelfth filtering branch; the fifth filtering branch and the eighth filtering branch are arranged at intervals, and the sixth filtering branch and the seventh filtering branch are arranged in front of the fifth filtering branch and the eighth filtering branch;

the second filtering cavity to the ninth filtering cavity of the fifth filtering branch and the second filtering cavity to the ninth filtering cavity of the fourth filtering branch are symmetrically arranged, and the second filtering cavity of the fifth filtering branch is intersected with the first filtering cavity;

the structures of the sixth filtering branch and the seventh filtering branch and the structures of the tenth filtering branch and the eleventh filtering branch are the same as the structures of the second filtering branch and the third filtering branch; the structure of the eighth filtering branch is the same as that of the fourth filtering branch; the structure of the ninth filtering branch is the same as that of the fifth filtering branch.

Preferably, the structures of the fifth to ninth filter cavities of the twelfth filter branch are the same as those of the fifth to ninth filter cavities of the fourth filter branch; the first filtering cavity, the second filtering cavity, the third filtering cavity and the fourth filtering cavity of the twelfth filtering branch are in a row and are sequentially arranged along the second direction;

and the fifth filter cavity of the twelfth filter branch is far away from the eleventh filter branch relative to the fourth filter cavity, and an included angle between a connecting line of the center of the fifth filter cavity and the center of the fourth filter cavity of the twelfth filter branch and a connecting line of the center of the third filter cavity and the center of the fourth filter cavity is an acute angle.

The present application provides a communication device of a communication system to solve the above technical problem. The communication system communication equipment comprises a terminal and a base station, wherein the base station comprises a base station antenna and a radio frequency unit connected with the antenna, and the radio frequency unit comprises the filter for filtering radio frequency signals.

The beneficial effects of the embodiment of the application are that: different from the prior art, the nine filter cavities of the first filter branch in the embodiment of the present application include two cross-coupling zeros; the second filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering branch comprise two cross-coupling zero points, so that zero point inhibition is realized, and indexes are convenient to debug; the product complexity can be reduced, the stability of the filter is improved, and the compact arrangement can reduce the size of the filter.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of an embodiment of a filter according to the present application;

fig. 2 is a schematic diagram of a topology of a first filtering branch of a filter provided in the present application;

FIG. 3 is a diagram illustrating simulation results of a first filtering branch of a filter provided in the present application;

fig. 4 is a schematic diagram of a topology of a second filtering branch of the filter provided in the present application;

FIG. 5 is a diagram illustrating simulation results of a second filtering branch of the filter provided by the present application;

fig. 6 is a schematic structural diagram of an embodiment of a communication device provided in the present application.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples. It is to be noted that the following examples are only illustrative of the present application, and do not limit the scope of the present application. Likewise, the following examples are only some examples and not all examples of the present application, and all other examples obtained by a person of ordinary skill in the art without any inventive step are within the scope of the present application.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the drawings described above, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or system that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or system.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an embodiment of a filter 10 according to the present application.

The filter 10 includes: the filter comprises a shell 101, a first filtering branch 11 and a second filtering branch 12.

A housing 101 having a first direction and a second direction D perpendicular to the first direction L;

the first filtering branch 11 is arranged on the shell 101 and consists of nine filtering cavities which are sequentially coupled, and the nine filtering cavities of the first filtering branch 11 comprise two cross-coupling zeros;

the second filtering branch 12 is arranged on the shell 101 and consists of eight filtering cavities which are coupled in sequence, and the eight filtering cavities of the second filtering branch 12 comprise two cross-coupling zeros;

the projections of the first filtering branch 11 and the second filtering branch 12 in the first direction L partially overlap. The first filtering branch 11 and the second filtering branch 12 are closely arranged, so that the size of the filter 10 can be reduced.

The first filter cavity TXA1, the second filter cavity TXA2, the third filter cavity TXA3 and the fourth filter cavity TXA4 of the first filter branch 11 are in a row and are sequentially arranged along the second direction D;

the fifth filtering cavity TXA5 of the first filtering branch 11 is far away from the second filtering branch 12 relative to the fourth filtering cavity TXA4, and an included angle between a connecting line of the center of the fifth filtering cavity TXA5 of the first filtering branch 11 and the center of the fourth filtering cavity TXA4 and a connecting line of the center of the third filtering cavity TXA3 and the center of the fourth filtering cavity TXA4 is an acute angle;

the fifth filtering cavity TXA4 and the eighth filtering cavity TXA8 of the first filtering branch 11 are in a row and are sequentially arranged along the second direction D;

the sixth filtering cavity TXA6 and the seventh filtering cavity TXA7 of the first filtering branch 11 are in a row and are sequentially arranged along the second direction D;

the ninth filtering cavity TXA9 of the first filtering branch 11 is closed to the second filtering branch 12 relative to the eighth filtering cavity TXA8, the ninth filtering cavity TXA9 of the first filtering branch 11 is adjacent to the seventh filtering cavity TXA7, and the ninth filtering cavity TXA9, the eighth filtering cavity TXA8 and the seventh filtering cavity TXA7 are arranged in a triangular shape.

The first filtering cavity RXA1, the second filtering cavity RXA2, the third filtering cavity RXA3, the fifth filtering cavity RXA5 and the eighth filtering cavity RXA8 of the second filtering branch 12 are in a row and are sequentially arranged along the second direction D;

the fourth filtering cavity RXA4, the sixth filtering cavity RXA6 and the seventh filtering cavity RXA7 of the second filtering branch 12 are in a row and are sequentially arranged along the second direction D;

the fourth filter cavity RXA4 of the second filter branch 12 is respectively arranged adjacent to the third filter cavity RXA3 and the fifth filter cavity RXA 5;

the sixth filter cavity RXA6 of the second filter branch 12 is respectively arranged adjacent to the fifth filter cavity RXA5 and the eighth filter cavity RXA 8;

the seventh filter cavity RXA7 of the second filter branch 12 is arranged adjacent to the eighth filter cavity RXA 8.

Referring to fig. 2, fig. 2 is a schematic diagram of a topology of a first filtering branch 11 of a filter 10 according to the present application.

The fifth filter chamber TXA5 and the eighth filter chamber TXA8 and the sixth filter chamber TXA6 and the eighth filter chamber TXA8 of the first filter branch 11 are respectively cross-coupled to form two cross-coupling zeros of the first filter branch 11;

specifically, a window may be disposed between the fifth filter cavity TXA5 of the first filter branch 11 and the eighth filter cavity TXA8 of the first filter branch 11, and a metal coupling rib is disposed on the window, so that the fifth filter cavity TXA5 of the first filter branch 11 and the eighth filter cavity TXA8 of the first filter branch 11 implement inductive cross coupling, and form an inductive cross coupling zero, which is equivalent to the inductor L1 shown in fig. 2. A window may be disposed between the sixth filtering cavity TXA6 of the first filtering branch 11 and the eighth filtering cavity TXA8 of the first filtering branch 11, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity TXA6 of the first filtering branch 11 and the eighth filtering cavity TXA8 of the first filtering branch 11 implement inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L2 shown in fig. 2. In this embodiment, the inductive cross coupling is realized by the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so as to prevent the filter 10 from generating the temperature drift.

The size of the first filter cavity TXA1 of the first filter branch 11, the size of the second filter cavity TXA2 of the first filter branch 11, the size of the third filter cavity TXA3 of the first filter branch 11, the size of the fourth filter cavity TXA4 of the first filter branch 11, the size of the fifth filter cavity TXA5 of the first filter branch 11, the size of the sixth filter cavity TXA6 of the first filter branch 11, the size of the seventh filter cavity TXA7 of the first filter branch 11, the size of the eighth filter cavity TXA8 of the first filter branch 11, and the size of the ninth filter cavity TXA9 of the first filter branch 11 may be the same. Namely, the nine filter cavities TXA1-TXA9 of the first filter branch 11 can be distributed at equal intervals, so that the layout and debugging are facilitated, and the consistency of the filter 10 is improved.

Referring to fig. 3, fig. 3 is a diagram illustrating simulation results of the first filtering branch 11 of the filter 10 according to the present application.

The first filtering branch 11 of this embodiment is composed of nine filtering cavities TXA1-TXA9 coupled in sequence, and the nine filtering cavities TXA1-TXA9 further form two inductive cross-coupling zeros W and zeros X, which can realize zero suppression and facilitate debugging of indexes; compared with the filter 10 in the prior art which is provided with capacitive cross coupling and inductive cross coupling at the same time, the two inductive cross coupling zeros W and the two inductive cross coupling zeros X of the present embodiment are made of the same material, so that the material types are reduced, the consistency of the material is improved, the product complexity is reduced, and the stability of the filter 10 is improved. In addition, in the embodiment, the inductive cross coupling is realized through the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so that the temperature drift of the filter 10 is avoided. In addition, the nine filter cavities TXA1-TXA9 are regularly distributed, so that the size of the filter 10 can be reduced; a plurality of filters 10 can be produced by the same die, so that the cost is reduced and the stability is high.

Optionally, the housing 101 is further provided with a first port (not shown) and a second port (not shown), and the first filtering chamber TXA1 of the first filtering branch 11 is coupled with the first port (not shown); the ninth filter chamber TXA9 of the first filter branch 11 is coupled to a second port (not shown). Wherein the first port (not shown) and the second port (not shown) may be taps of the filter 10.

The bandwidth of the first filtering branch 11 of this embodiment is in the range 2110Mhz-2170 Mhz. Specifically, in the first filtering branch 11, the coupling bandwidth between the first port (not shown) and the first filtering cavity TXA1 is in the range of 50Mhz to 60 Mhz; the coupling bandwidth between the first filter chamber TXA1 and the second filter chamber TXA2 ranges from 42Mhz to 51 Mhz; the coupling bandwidth between the second filter chamber TXA2 and the third filter chamber TXA3 ranges from 30Mhz to 37 Mhz; the coupling bandwidth between the third filter chamber TXA3 and the fourth filter chamber TXA4 ranges from 28Mhz to 35 Mhz; the coupling bandwidth between the fourth filter chamber TXA4 and the fifth filter chamber TXA5 ranges from 27Mhz to 34 Mhz; the coupling bandwidth between the fifth filter cavity TXA5 and the sixth filter cavity TXA6 ranges from 26Mhz to 33 Mhz; the coupling bandwidth between the sixth filter cavity TXA6 and the seventh filter cavity TXA7 ranges from 9Mhz to 14 Mhz; the coupling bandwidth between the sixth filter cavity TXA6 and the eighth filter cavity TXA8 ranges from 7Mhz to 12 Mhz; the coupling bandwidth between the fifth filter chamber TXA5 and the eighth filter chamber TXA8 ranges from 23Mhz to 30 Mhz; the coupling bandwidth between the seventh filter cavity TXA7 and the eighth filter cavity TXA8 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the eighth filter chamber TXA8 and the ninth filter chamber TXA9 ranges from 42Mhz to 51 Mhz; the coupling bandwidth between the ninth filter cavity TXA9 and the second port (not shown) is in the range of 50Mhz-60 Mhz. Therefore, the bandwidth of the first filtering branch 11 of the present embodiment is located at 2110Mhz-2170Mhz, which can meet the design requirement. Therefore, the resonant frequencies of the first filter chamber TXA1 to the ninth filter chamber TXA9 of the first filter branch 11 are in the following ranges in sequence: 2138Mhz-2140Mhz, 2146Mhz-2148Mhz, 2165Mhz-2167Mhz, 2138Mhz-2140 Mhz.

Experimentally tested, the bandwidth of the filter 10 of the present application was in the range 2110Mhz-2170Mhz, as shown by the band curve 20 in fig. 3. The zero point W and the zero point X are two inductive cross-coupling zero points in the first filtering branch 11 of the filter 10 of the present application.

The first filtering branch 11 bandwidth rejection satisfies the following table:

1980MHz	＞100dB
		2025MHz	＞80dB
2100MHz	＞15dB
		2105MHz	＞8dB
2180MHz	＞8dB
		2300MHz	＞35dB
2400MHz	＞75dB

referring to fig. 4, fig. 4 is a schematic diagram of a topology of the second filtering branch 12 of the filter 10 according to the present application.

The third filter cavity RXA3 and the fifth filter cavity RXA5 and the sixth filter cavity RXA6 and the eighth filter cavity RXA8 of the second filter branch 12 are cross-coupled to form two cross-coupled zeros of the second filter branch 12, respectively.

Specifically, a window may be disposed between the sixth filtering cavity RXA6 of the second filtering branch 12 and the eighth filtering cavity RXA8 of the second filtering branch 12, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity RXA6 of the second filtering branch 12 and the eighth filtering cavity RXA8 of the second filtering branch 12 implement inductive cross-coupling, and an inductive cross-coupling zero point is formed, which is equivalent to the inductor L3 shown in fig. 4. In this embodiment, the inductive cross coupling is realized by the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so as to prevent the filter 10 from generating the temperature drift.

Specifically, the capacitive coupling zero point is realized by a capacitive cross-coupling element, and a general capacitive cross-coupling element may be a flying bar; namely, a flying bar is arranged between the third filtering cavity RXA3 of the second filtering branch 12 and the fifth filtering cavity RXA5 of the second filtering branch 12; the effect of realizing capacitive coupling zero point is achieved, which is equivalent to the capacitor C1 shown in FIG. 4, zero point suppression is realized, and the production cost is reduced; the consistency of the single-capacity material is good.

The size of the first filter cavity RXA1 of the second filter branch 12, the size of the second filter cavity RXA2 of the second filter branch 12, the size of the third filter cavity RXA3 of the second filter branch 12, the size of the fourth filter cavity RXA4 of the second filter branch 12, the size of the fifth filter cavity RXA5 of the second filter branch 12, the size of the sixth filter cavity RXA6 of the second filter branch 12, the size of the seventh filter cavity RXA7 of the second filter branch 12, and the size of the eighth filter cavity RXA8 of the second filter branch 12 may be the same. Namely, the eight filter cavities RXA1-RXA8 of the second filter branch 12 can be distributed equidistantly, which is convenient for layout and debugging, and improves the consistency of the filter 10.

Referring to fig. 5, fig. 5 is a diagram illustrating simulation results of the second filtering branch 12 of the filter 10 according to the present application.

The second filtering branch 12 of this embodiment is composed of eight filtering cavities RXA1-RXA8 coupled in sequence, and the eight filtering cavities RXA1-RXA8 further form an inductive cross-coupling zero Y and a capacitive cross-coupling zero Z, which can achieve high isolation, and particularly, an inductive cross-coupling is provided between the third filtering cavity RXA3 of the second filtering branch 12 and the fifth filtering cavity RXA5 of the second filtering branch 12, and an inductive cross-coupling is provided between the sixth filtering cavity RXA6 of the second filtering branch 12 and the eighth filtering cavity RXA8 of the second filtering branch 12, which greatly improves out-of-band rejection performance, has high isolation, and improves radio frequency performance index. Optionally, the housing 101 is further provided with a third port (not shown) and a fourth port (not shown), and the first filter cavity RXA1 of the second filter branch 12 is coupled with the third port (not shown); the eighth filter cavity RXA8 of the second filter branch 12 is coupled to a fourth port (not shown). Wherein the third port (not shown) and the fourth port (not shown) may be taps of the filter 10.

The bandwidth of the second filtering branch 12 in this embodiment lies in the range 1920Mhz-1980 Mhz. In particular, in the second filtering branch 12, the coupling bandwidth between the third port (not shown) and the first filtering cavity RXA1 is in the range of 51Mhz-61 Mhz; the coupling bandwidth between the first filter cavity RXA1 and the second filter cavity RXA2 ranges from 42Mhz to 51 Mhz; the coupling bandwidth between the second filter cavity RXA2 and the third filter cavity RXA3 ranges from 30Mhz to 37 Mhz; the coupling bandwidth between the third filter cavity RXA3 and the fourth filter cavity RXA4 ranges from 26Mhz to 33 Mhz; the coupling bandwidth between the third filter cavity RXA3 and the fifth filter cavity RXA5 ranges from 8Mhz to 13 Mhz; the coupling bandwidth between the fourth filter cavity RXA4 and the fifth filter cavity RXA5 ranges from 26Mhz to 33 Mhz; the coupling bandwidth between the fifth filter cavity RXA5 and the sixth filter cavity RXA6 ranges from 28Mhz to 35 Mhz; the coupling bandwidth between the sixth filter cavity RXA6 and the seventh filter cavity RXA7 ranges from 25Mhz to 32 Mhz; the coupling bandwidth between the sixth filter cavity RXA6 and the eighth filter cavity RXA8 ranges from 18Mhz to 24 Mhz; the coupling bandwidth between the seventh filter cavity RXA7 and the eighth filter cavity RXA8 ranges from 38Mhz-46 Mhz; the coupling bandwidth between the eighth filter cavity RXA8 and the fourth port (not shown) is in the range of 51Mhz-61 Mhz. Therefore, the bandwidth of the second filtering branch 12 of the present embodiment is located in 1920Mhz-1980Mhz, which can meet the design requirement.

Therefore, the resonant frequencies of the first filtering cavity RXA1 through the eighth filtering cavity RXA8 of the second filtering branch 12 are sequentially located in the following ranges: 1949Mhz-1951Mhz, 1938Mhz-1940Mhz, 1948Mhz-1950Mhz, 1947Mhz-1949Mhz, 1965Mhz-1967Mhz, 1949Mhz-1951 Mhz.

Experimentally tested, the bandwidth of the filter 10 of the present application is in the range of 1920Mhz-1980Mhz, as shown by the band curve 21 in fig. 5. The zero Y and the zero Z are inductive cross-coupling zeros and capacitive cross-coupling zeros in the second filtering branch 12 of the filter 10 of the present application.

The second filtering branch 12 bandwidth rejection satisfies the following table:

the filter 10 further includes a third filtering branch 13 and a fourth filtering branch 14, the third filtering branch 13 and the second filtering branch 12 are divided into three rows arranged in sequence along the first direction L, and the fourth filtering branch 14 is divided into two rows arranged in sequence along the first direction L.

The first filter cavity, the fourth filter cavity, the sixth filter cavity, the seventh filter cavity and the eighth filter cavity of the third filter branch 13 are in a row and are sequentially arranged along the second direction D;

the second filter cavity, the fourth filter cavity and the fifth filter cavity of the third filter branch 13, and the fourth filter cavity, the sixth filter cavity and the seventh filter cavity of the second filter branch 12 are in a row and are sequentially arranged along the second direction D.

The first filter cavity, the second filter cavity, the third filter cavity, the fourth filter cavity, the fifth filter cavity, the eighth filter cavity and the ninth filter cavity of the fourth filter branch 14 are in a row and are sequentially arranged along the second direction D;

the sixth filtering cavities and the seventh filtering cavities of the fourth filtering branch 14 are in a row and are sequentially arranged along the second direction D;

a sixth filter cavity of the fourth filter branch 14 is respectively adjacent to the fifth filter cavity, the seventh filter cavity, the eighth filter cavity and the sixth filter cavity of the first filter branch 11;

a first filter cavity of the fourth filter branch 14 is adjacent to a first filter cavity of the third filter branch 13, and a second filter cavity of the fourth filter branch 14 is adjacent to a fourth filter cavity of the third filter branch 13;

the eighth filter cavity of the third filter branch 13 is respectively adjacent to the seventh filter cavity and the sixth filter cavity of the second filter branch 12 and the fourth filter cavity of the fourth filter branch 14;

the first filtering cavity and the third filtering cavity of the third filtering branch 13 and the fourth filtering cavity and the sixth filtering cavity of the third filtering branch 13 are respectively cross-coupled to form two cross-coupling zeros of the third filtering branch 13;

the fifth filtering cavity and the eighth filtering cavity of the fourth filtering branch 14 and the sixth filtering cavity and the eighth filtering cavity are respectively cross-coupled to form two cross-coupling zeros of the fourth filtering branch 14.

As shown in fig. 2, the fifth filter chamber TXB5 and the eighth filter chamber TXB8 and the sixth filter chamber TXB6 and the eighth filter chamber TXB8 of the third filter branch 13 are cross-coupled to form two cross-coupling zeros of the third filter branch 13;

specifically, a window may be disposed between the fifth filter cavity TXB5 of the third filter branch 13 and the eighth filter cavity TXB8 of the third filter branch 13, and a metal coupling rib is disposed on the window, so that the fifth filter cavity TXB5 of the third filter branch 13 and the eighth filter cavity TXB8 of the third filter branch 13 implement inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L1 shown in fig. 2. A window may be disposed between the sixth filtering cavity TXB6 of the third filtering branch 13 and the eighth filtering cavity TXB8 of the third filtering branch 13, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity TXB6 of the third filtering branch 13 and the eighth filtering cavity TXB8 of the third filtering branch 13 implement inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L2 shown in fig. 2. In this embodiment, the inductive cross coupling is realized by the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so as to prevent the filter 10 from generating the temperature drift.

The size of the first filter cavity TXB1 of the third filter branch 13, the size of the second filter cavity TXB2 of the third filter branch 13, the size of the third filter cavity TXB3 of the third filter branch 13, the size of the fourth filter cavity TXB4 of the third filter branch 13, the size of the fifth filter cavity TXB5 of the third filter branch 13, the size of the sixth filter cavity TXB6 of the third filter branch 13, the size of the seventh filter cavity TXB7 of the third filter branch 13, the size of the eighth filter cavity TXB8 of the third filter branch 13, and the size of the ninth filter cavity TXB9 of the third filter branch 13 may be the same. Namely, the nine filter cavities TXB1-TXB9 of the third filter branch 13 can be distributed at equal intervals, so that the layout and debugging are facilitated, and the consistency of the filter 10 is improved.

As shown in fig. 3, the third filtering branch 13 of the present embodiment is composed of nine filtering cavities TXB1-TXB9 coupled in sequence, and the nine filtering cavities TXB1-TXB9 further form two inductive cross-coupling zeros W and zeros X, which can implement zero suppression and facilitate debugging of indexes; compared with the filter 10 in the prior art which is provided with capacitive cross coupling and inductive cross coupling at the same time, the two inductive cross coupling zeros W and the two inductive cross coupling zeros X of the present embodiment are made of the same material, so that the material types are reduced, the consistency of the material is improved, the product complexity is reduced, and the stability of the filter 10 is improved. In addition, in the embodiment, the inductive cross coupling is realized through the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so that the temperature drift of the filter 10 is avoided. In addition, the nine filter cavities TXB1-TXB9 are regularly distributed, so that the size of the filter 10 can be reduced; a plurality of filters 10 can be produced by the same die, so that the cost is reduced and the stability is high.

Optionally, the housing 101 is further provided with a fifth port (not shown) and a sixth port (not shown), and the first filtering chamber TXB1 of the third filtering branch 13 is coupled with the fifth port (not shown); the ninth filter chamber TXB9 of the third filter branch 13 is coupled to a sixth port (not shown). Wherein the fifth port (not shown) and the sixth port (not shown) may be taps of the filter 10.

The bandwidth of the third filtering branch 13 of the present embodiment is in the range 2110Mhz-2170 Mhz. Specifically, in the third filtering branch 13, the coupling bandwidth between the fifth port (not shown) and the first filtering cavity TXB1 is in the range of 50Mhz to 60 Mhz; the coupling bandwidth between the first filter chamber TXB1 and the second filter chamber TXB2 ranges from 42Mhz to 51 Mhz; the coupling bandwidth between the second filter chamber TXB2 and the third filter chamber TXB3 ranges from 30Mhz to 37 Mhz; the coupling bandwidth between the third filter chamber TXB3 and the fourth filter chamber TXB4 ranges from 28Mhz to 35 Mhz; the coupling bandwidth between the fourth filter cavity TXB4 and the fifth filter cavity TXB5 ranges from 27Mhz to 34 Mhz; the coupling bandwidth between the fifth filter cavity TXB5 and the sixth filter cavity TXB6 ranges from 26Mhz to 33 Mhz; the coupling bandwidth between the sixth filter cavity TXB6 and the seventh filter cavity TXB7 ranges from 9Mhz to 14 Mhz; the coupling bandwidth between the sixth filter cavity TXB6 and the eighth filter cavity TXB8 ranges from 7Mhz to 12 Mhz; the coupling bandwidth between the fifth filter cavity TXB5 and the eighth filter cavity TXB8 ranges from 23Mhz to 30 Mhz; the coupling bandwidth between the seventh filter cavity TXB7 and the eighth filter cavity TXB8 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the eighth filter cavity TXB8 and the ninth filter cavity TXB9 ranges from 42Mhz to 51 Mhz; the coupling bandwidth between the ninth filter cavity TXB9 and the sixth port (not shown) ranges from 50Mhz to 60 Mhz. Therefore, the bandwidth of the third filtering branch 13 of the present embodiment is located at 2110Mhz-2170Mhz, which can meet the design requirement. Therefore, the resonant frequencies of the first filter chamber TXB1 to the ninth filter chamber TXB9 of the third filter branch 13 are sequentially in the following ranges: 2138Mhz-2140Mhz, 2146Mhz-2148Mhz, 2165Mhz-2167Mhz, 2138Mhz-2140 Mhz.

Experimentally tested, the bandwidth of the filter 10 of the present application was in the range 2110Mhz-2170Mhz, as shown by the band curve 20 in fig. 3. The zero point W and the zero point X are two inductive cross-coupling zero points in the third filtering branch 13 of the filter 10 of the present application.

The third filtering branch 13 bandwidth rejection satisfies the following table:

as shown in fig. 4, the third filter cavity RXB3 and the fifth filter cavity RXB5 and the sixth filter cavity RXB6 and the eighth filter cavity RXB8 of the fourth filter branch 14 are cross-coupled to form two cross-coupled zeros of the fourth filter branch 14, respectively.

Specifically, a window may be disposed between the fourth filtering cavity RXB4 of the fourth filtering branch 14 and the sixth filtering cavity RXB6 of the fourth filtering branch 14, and a metal coupling rib is disposed on the window, so that the fourth filtering cavity RXB4 of the fourth filtering branch 14 and the sixth filtering cavity RXB6 of the fourth filtering branch 14 implement inductive cross-coupling, and an inductive cross-coupling zero point is formed, which is equivalent to the inductor L3 shown in fig. 4. In this embodiment, the inductive cross coupling is realized by the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so as to prevent the filter 10 from generating the temperature drift.

Specifically, the capacitive coupling zero point is realized by a capacitive cross-coupling element, and a general capacitive cross-coupling element may be a flying bar; namely, a flying bar is arranged between the first filtering cavity RXB1 of the fourth filtering branch 14 and the third filtering cavity RXB3 of the fourth filtering branch 14; the effect of realizing capacitive coupling zero point is achieved, which is equivalent to the capacitor C1 shown in FIG. 4, zero point suppression is realized, and the production cost is reduced; the consistency of the single-capacity material is good.

The size of the first filter cavity RXB1 of the fourth filter branch 14, the size of the second filter cavity RXB2 of the fourth filter branch 14, the size of the third filter cavity RXB3 of the fourth filter branch 14, the size of the fourth filter cavity RXB4 of the fourth filter branch 14, the size of the fifth filter cavity RXB5 of the fourth filter branch 14, the size of the sixth filter cavity RXB6 of the fourth filter branch 14, the size of the seventh filter cavity RXB7 of the fourth filter branch 14, and the size of the eighth filter cavity RXB8 of the fourth filter branch 14 may be the same. Namely, the eight filter cavities RXB1-RXB8 of the fourth filter branch 14 may be distributed equidistantly, which is convenient for layout and debugging, and improves the consistency of the filter 10.

As shown in fig. 5, the fourth filtering branch 14 of this embodiment is composed of eight filtering cavities RXB1-RXB8 coupled in sequence, and the eight filtering cavities RXB1-RXB8 further form an inductive cross-coupling zero Y and a capacitive cross-coupling zero Z, so as to achieve high isolation, and in particular, an inductive cross-coupling is provided between the first filtering cavity RXB1 of the fourth filtering branch 14 and the third filtering cavity RXB3 of the fourth filtering branch 14, and an inductive cross-coupling is provided between the fourth filtering cavity RXB4 of the fourth filtering branch 14 and the sixth filtering cavity RXB6 of the fourth filtering branch 14, so as to greatly improve out-of-band rejection performance, high isolation, and improve radio frequency performance index. Optionally, the housing 101 is further provided with a seventh port (not shown) and an eighth port (not shown), and the first filter cavity RXB1 of the fourth filter branch 14 is coupled with the seventh port (not shown); the eighth filter cavity RXB8 of the fourth filter branch 14 is coupled to an eighth port (not shown). Wherein the seventh port (not shown) and the eighth port (not shown) may be taps of the filter 10.

The bandwidth of the fourth filtering branch 14 in this embodiment is in the range of 1920Mhz-1980 Mhz. In particular, in the fourth filtering branch 14, the coupling bandwidth between the seventh port (not shown) and the first filtering cavity RXB1 is in the range of 51Mhz-61 Mhz; the coupling bandwidth between the first filter cavity RXB1 and the second filter cavity RXB2 ranges from 39Mhz to 48 Mhz; the coupling bandwidth between the first filter cavity RXB1 and the third filter cavity RXB3 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the second filter cavity RXB2 and the third filter cavity RXB3 ranges from 27Mhz to 34 Mhz; the coupling bandwidth between the third filter cavity RXB3 and the fourth filter cavity RXB4 ranges from 28Mhz to 35 Mhz; the coupling bandwidth between the fourth filter cavity RXB4 and the fifth filter cavity RXB5 ranges from 24Mhz-31 Mhz; the coupling bandwidth between the fourth filter cavity RXB4 and the sixth filter cavity RXB6 ranges from 11Mhz to 16 Mhz; the coupling bandwidth between the fifth filter cavity RXB5 and the sixth filter cavity RXB6 ranges from 25Mhz to 32 Mhz; the coupling bandwidth between the sixth filter cavity RXB6 and the seventh filter cavity RXB7 ranges from 30Mhz to 37 Mhz; the coupling bandwidth between the seventh filter cavity RXB7 and the eighth filter cavity RXB8 ranges from 42Mhz-51 Mhz; the coupling bandwidth between the eighth filter cavity RXB8 and the eighth port (not shown) is in the range of 51Mhz-61 Mhz. Therefore, the bandwidth of the fourth filtering branch 14 of the present embodiment is located in 1920Mhz-1980Mhz, which can meet the design requirement.

Therefore, the resonant frequencies of the first filtering cavity RXB1 through the eighth filtering cavity RXB8 of the fourth filtering branch 14 are sequentially located in the following ranges: 1949Mhz-1951Mhz, 1936Mhz-1938Mhz, 1950Mhz-1952Mhz, 1949Mhz-1951Mhz, 1962Mhz-1964Mhz, 1949Mhz-1951Mhz, and 1949Mhz-1951 Mhz.

Experimentally tested, the bandwidth of the filter 10 of the present application is in the range of 1920Mhz-1980Mhz, as shown by the band curve 21 in fig. 5. The zero Y and the zero Z are inductive cross-coupling zeros and capacitive cross-coupling zeros in the fourth filtering branch 14 of the filter 10 of the present application.

The fourth filtering branch 14 bandwidth rejection satisfies the following table:

1880MHz	＞75dB
		1900MHz	＞25dB
1910MHz	＞12dB
		1915MHz	＞2dB
2000MHz	＞25dB
		2010MHz	＞56dB
2050MHz	＞35dB

the filter 10 further includes a fifth filtering branch 15, a sixth filtering branch 16, a seventh filtering branch 17, an eighth filtering branch 18, a ninth filtering branch 19, a tenth filtering branch 110, an eleventh filtering branch 111, and a twelfth filtering branch 112;

the fifth filtering branch 15 and the eighth filtering branch 18 are arranged at intervals, and the sixth filtering branch 16 and the seventh filtering branch 17 are arranged in front of the fifth filtering branch 15 and the eighth filtering branch 18;

the second to ninth filter cavities of the fifth filter branch 15 and the second to ninth filter cavities of the fourth filter branch 14 are symmetrically arranged, and the second filter cavity of the fifth filter branch 15 intersects with the first filter cavity;

the structures of the sixth filtering branch 16 and the seventh filtering branch 17, and the structures of the tenth filtering branch 110 and the eleventh filtering branch 111 are the same as those of the second filtering branch 12 and the third filtering branch 13;

the structure of the eighth filtering branch 18 is the same as that of the fourth filtering branch 14;

the eighth filtering branch 18 is disposed adjacent to the sixth filtering branch 16 and the seventh filtering branch 17, respectively.

The ninth filtering branch 19 has the same structure as the fifth filtering branch 15.

The ninth filtering branch 19 is disposed adjacent to the seventh filtering branch 17 and the tenth filtering branch, respectively.

The structures of the fifth to ninth filter cavities of the twelfth filter branch 112 are the same as those of the fifth to ninth filter cavities of the fourth filter branch 14;

the first filter cavity, the second filter cavity, the third filter cavity and the fourth filter cavity of the twelfth filter branch 112 are in a row and are sequentially arranged along the second direction D;

a fifth filter cavity of the twelfth filter branch 112 is far away from the eleventh filter branch 111 relative to the fourth filter cavity, and an included angle between a connecting line of the fifth filter cavity center and the fourth filter cavity center of the twelfth filter branch 112 and a connecting line of the third filter cavity center and the fourth filter cavity center is an acute angle.

Referring to fig. 6, fig. 6 is a schematic structural diagram of an embodiment of a communication device 60 provided in the present application.

The present application also provides a communication device 60, and the communication device 60 of the present embodiment includes an antenna 62 and a radio frequency unit 61. The antenna 62 and the radio frequency unit 61 can be installed on a base station, and can also be installed on objects such as a street lamp; the antenna 62 is connected to a Radio Unit (RRU) 61. The rf unit 61 includes the filter 10 disclosed in the above embodiments for filtering the rf signal.

In other embodiments, the rf Unit 61 may be integrated with the Antenna 62 to form an Active Antenna Unit (AAU).

The principle and the implementation of the present application are explained herein by applying specific examples, and the above description of the embodiments is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims

1. A filter, characterized in that the filter comprises:

a housing having a first direction and a second direction perpendicular to the first direction;

the first filtering branch is arranged on the shell and consists of nine filtering cavities which are sequentially coupled, and the nine filtering cavities of the first filtering branch comprise two cross-coupling zeros;

the second filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering branch comprise two cross-coupling zeros;

the projection parts of the first filtering branch and the second filtering branch in the first direction are overlapped.

2. The filter of claim 1,

the first filtering cavity, the second filtering cavity, the third filtering cavity and the fourth filtering cavity of the first filtering branch are in a row and are sequentially arranged along the second direction;

the fifth filter cavity of the first filter branch is far away from the second filter branch relative to the fourth filter cavity, and an included angle between a connecting line of the center of the fifth filter cavity of the first filter branch and the center of the fourth filter cavity and a connecting line of the center of the third filter cavity and the center of the fourth filter cavity is an acute angle;

the fifth filtering cavities and the eighth filtering cavities of the first filtering branch are in a row and are sequentially arranged along the second direction;

the sixth filtering cavities and the seventh filtering cavities of the first filtering branch are in a row and are sequentially arranged along the second direction;

the ninth filtering cavity of the first filtering branch is close to the second filtering branch relative to the eighth filtering cavity, the ninth filtering cavity and the seventh filtering cavity of the first filtering branch are adjacent, and the ninth filtering cavity, the eighth filtering cavity and the seventh filtering cavity are triangular.

3. The filter of claim 2,

the first filtering cavity, the second filtering cavity, the third filtering cavity, the fifth filtering cavity and the eighth filtering cavity of the second filtering branch are in a row and are sequentially arranged along the second direction;

the fourth filtering cavity, the sixth filtering cavity and the seventh filtering cavity of the second filtering branch are in a row and are sequentially arranged along the second direction;

a fourth filter cavity of the second filter branch is respectively adjacent to the third filter cavity and the fifth filter cavity;

a sixth filter cavity of the second filter branch is respectively adjacent to the fifth filter cavity and the eighth filter cavity;

and a seventh filtering cavity and an eighth filtering cavity of the second filtering branch are arranged adjacently.

4. The filter of claim 3,

the fifth filtering cavity and the eighth filtering cavity of the first filtering branch circuit and the sixth filtering cavity and the eighth filtering cavity of the first filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the first filtering branch circuit;

and the third filtering cavity and the fifth filtering cavity of the second filtering branch circuit and the sixth filtering cavity and the eighth filtering cavity of the second filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the second filtering branch circuit.

5. The filter according to claim 3, further comprising a third filtering branch and a fourth filtering branch, wherein the third filtering branch and the second filtering branch are divided into three columns arranged in sequence along the first direction, and the fourth filtering branch is divided into two columns arranged in sequence along the first direction.

6. The filter of claim 5,

the first filtering cavity, the fourth filtering cavity, the sixth filtering cavity, the seventh filtering cavity and the eighth filtering cavity of the third filtering branch are in a row and are sequentially arranged along the second direction;

and the second filtering cavity, the fourth filtering cavity and the fifth filtering cavity of the third filtering branch circuit, and the fourth filtering cavity, the sixth filtering cavity and the seventh filtering cavity of the second filtering branch circuit are in a row and are sequentially arranged along the second direction.

7. The filter according to claim 5, wherein the first filter cavity, the second filter cavity, the third filter cavity, the fourth filter cavity, the fifth filter cavity, the eighth filter cavity and the ninth filter cavity of the fourth filter branch are in a row and are sequentially arranged along the second direction;

the sixth filtering cavities and the seventh filtering cavities of the fourth filtering branch are in a row and are sequentially arranged along the second direction;

a sixth filter cavity of the fourth filter branch is respectively adjacent to a fifth filter cavity, a seventh filter cavity, an eighth filter cavity and the sixth filter cavity of the first filter branch;

the first filter cavity of the fourth filter branch is arranged adjacent to the first filter cavity of the third filter branch, and the second filter cavity of the fourth filter branch is arranged adjacent to the fourth filter cavity of the third filter branch;

the eighth filter cavity of the third filter branch is respectively adjacent to the seventh filter cavity and the sixth filter cavity of the second filter branch and the fourth filter cavity of the fourth filter branch;

the fifth filtering cavity and the eighth filtering cavity of the third filtering branch circuit and the sixth filtering cavity and the eighth filtering cavity of the third filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the third filtering branch circuit;

and the first filtering cavity and the third filtering cavity of the fourth filtering branch circuit and the fourth filtering cavity and the sixth filtering cavity of the fourth filtering branch circuit are respectively in cross coupling so as to form two cross coupling zeros of the fourth filtering branch circuit.

8. The filter of claim 7,

the filter also comprises a fifth filtering branch, a sixth filtering branch, a seventh filtering branch, an eighth filtering branch, a ninth filtering branch, a tenth filtering branch, an eleventh filtering branch and a twelfth filtering branch;

the fifth filtering branch and the eighth filtering branch are arranged at intervals, and the sixth filtering branch and the seventh filtering branch are arranged in front of the fifth filtering branch and the eighth filtering branch;

the structures of the sixth filtering branch and the seventh filtering branch and the structures of the tenth filtering branch and the eleventh filtering branch are the same as the structures of the second filtering branch and the third filtering branch;

the structure of the eighth filtering branch is the same as that of the fourth filtering branch;

the structure of the ninth filtering branch is the same as that of the fifth filtering branch.

9. The filter of claim 8,

the structures of a fifth filtering cavity to a ninth filtering cavity of the twelfth filtering branch are the same as the structures of the fifth filtering cavity to the ninth filtering cavity of the fourth filtering branch;

the first filtering cavity, the second filtering cavity, the third filtering cavity and the fourth filtering cavity of the twelfth filtering branch are in a row and are sequentially arranged along the second direction;

and an included angle between a connecting line of the fifth filter cavity center and the fourth filter cavity center of the twelfth filter branch and a connecting line of the third filter cavity center and the fourth filter cavity center is an acute angle.

10. A communication device, characterized in that the communication device comprises an antenna and a radio frequency unit connected to the antenna, the radio frequency unit comprising a filter according to any of claims 1-9 for filtering radio frequency signals.