CN113131119A

CN113131119A - Communication system and filter thereof

Info

Publication number: CN113131119A
Application number: CN201911383528.0A
Authority: CN
Inventors: 周峰; 韩军平; 宋文刚; 陈砚昌
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: 2021-07-16

Abstract

The application discloses a communication system and a filter thereof. The filter includes: the first filtering branch is arranged on the first surface and coupled with the first common cavity; the second filtering branch is arranged on the first surface and coupled with the first common cavity; a first filtering cavity of the first filtering branch, a first filtering cavity of the second filtering branch and a fifth filtering cavity of the second filtering branch are respectively intersected with the first common cavity; the third filtering branch is arranged on the second surface and coupled with the second common cavity; the fourth filtering branch is arranged on the second surface and coupled with the second common cavity; the first filter cavity of the third filter branch, the first filter cavity of the fourth filter branch and the second filter cavity of the fourth filter branch are respectively intersected with the second common cavity, and by the mode, the number of taps can be reduced by arranging the common cavities, and the size of the filter is reduced; the size of the filter is reduced through the arrangement of the front side and the back side, and the cost is reduced; the distance between the centers of the two filtering cavities can be reduced through the intersecting arrangement, the coupling is enhanced, the materials are reduced, and the processing is convenient.

Description

Communication system 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 precisely control its bandwidth.

The inventor of the application finds that in long-term research and development work, each existing filtering branch needs to be provided with a tap independently, and the number of the taps is too large, so that the number of required welding points is too large, the size of the filter is not reduced, and the stability of the filter is influenced; moreover, only one surface of the existing filter is provided with the filter cavity, and when the number of the filter cavities is large, the size of the filter is large, and the production cost is high; the distance between the filter cavities of the existing filter is too large, and the coupling effect is poor.

Disclosure of Invention

The application provides a filter to solve the filter of prior art and take a percentage quantity too much, lead to required welding point also more, the required volume of filter is big, and manufacturing cost is high, and the distance between the filter chamber is too big, the poor technical problem of coupling effect.

To solve the above problem, an embodiment of the present application provides a filter, where the filter includes:

a housing having a first direction and a second direction perpendicular to each other;

the first common cavity is arranged on the first surface of the shell, and the second common cavity is arranged on the second surface of the shell;

the first filtering branch is arranged on the first surface, is coupled with the first common cavity and consists of ten filtering cavities which are sequentially coupled, and four cross-coupling zeros are further formed by the ten filtering cavities of the first filtering branch;

the second filtering branch is arranged on the first surface, is coupled with the first common cavity, and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering cavity branch further form three cross-coupling zero points;

the first filtering cavity of the first filtering branch, the first filtering cavity of the second filtering branch and the fifth filtering cavity of the second filtering branch are respectively intersected with the first common cavity;

the third filtering branch is arranged on the second surface, is coupled with the second common cavity and consists of eleven filtering cavities which are sequentially coupled, and the eleven filtering cavities of the third filtering branch further form three cross-coupling zeros;

the fourth filtering branch is arranged on the second surface, is coupled with the second common cavity and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the fourth filtering cavity branch further form two cross-coupling zero points;

and the first filtering cavity of the third filtering branch, the first filtering cavity of the fourth filtering branch and the second filtering cavity of the fourth filtering branch are respectively intersected with the second common cavity.

Compared with the prior art, the filter of this application includes: a housing having a first direction and a second direction perpendicular to each other; the first common cavity is arranged on the first surface of the shell, and the second common cavity is arranged on the second surface of the shell; the first filtering branch is arranged on the first surface, is coupled with the first common cavity and consists of ten filtering cavities which are sequentially coupled, and the ten filtering cavities of the first filtering branch further form four cross-coupling zeros; the second filtering branch is arranged on the first surface, is coupled with the first common cavity and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering cavity branch further form three cross-coupling zero points; a first filtering cavity of the first filtering branch, a first filtering cavity of the second filtering branch and a fifth filtering cavity of the second filtering branch are respectively intersected with the first common cavity; the third filtering branch is arranged on the second surface, is coupled with the second common cavity and consists of eleven filtering cavities which are sequentially coupled, and the eleven filtering cavities of the third filtering branch further form three cross-coupling zero points; the fourth filtering branch is arranged on the second surface, is coupled with the second common cavity and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the fourth filtering cavity branch further form two cross-coupling zero points; the first filter cavity of the third filter branch, the first filter cavity of the fourth filter branch and the second filter cavity of the fourth filter branch are respectively intersected with the second common cavity; by the mode, the number of taps can be reduced by arranging the common cavity, required welding points are reduced, and the size of the filter is reduced; the size of the filter is reduced through the arrangement of the front side and the back side, and the cost is reduced; the zero point suppression can be realized by the cross coupling zero point, so that the indexes are convenient to debug and the design requirements are met; the distance between the centers of the two filtering cavities can be reduced by intersecting the filtering cavities, the coupling is enhanced, the situation that a partition wall needs to be arranged between the two filtering cavities which are sequentially coupled in the traditional filtering cavity is avoided, then a coupling window is formed on the partition wall, the materials are reduced, and the processing is convenient.

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 provided herein;

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

fig. 3 is a schematic diagram of a topology of a second filtering branch provided in the present application;

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

fig. 5 is a schematic diagram of a topology of a fourth filtering branch provided in the present application;

FIG. 6 is a schematic diagram of another embodiment of a filter provided herein;

fig. 7 is a schematic diagram of a topology of a fifth filtering branch provided in the present application;

fig. 8 is a schematic diagram of a topology of a sixth filtering branch provided in the present application;

fig. 9 is a schematic diagram of a topology of a seventh filtering branch provided in the present application;

fig. 10 is a schematic diagram of a topology of an eighth filtering branch provided in the present application;

FIG. 11 is a diagram illustrating simulation results of a filter provided herein;

fig. 12 is a schematic structural diagram of an embodiment of a communication system 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.

The present application provides a filter, as shown in fig. 1, fig. 1 is a schematic structural diagram of an embodiment of the filter of the present application. The filter 10 of the present embodiment includes a housing 11, and the housing 11 has a first direction L and a second direction D, and the first direction L of the housing 11 is disposed perpendicular to the second direction D of the housing 11. The housing 11 further includes front and back sides, i.e., a first surface 111 and a second surface 112.

The filter 10 further comprises a first common cavity 12, a first filtering branch 14 and a second filtering branch 15 arranged on the first surface 111, and a second common cavity 13, a third filtering branch 16 and a fourth filtering branch 17 arranged on the second surface 112. The first filtering branch 14, the second filtering branch 15, the third filtering branch 16 and the fourth filtering branch 17 may be a receiving filtering branch and a transmitting filtering branch, respectively, or may also be a receiving filtering branch or a transmitting filtering branch. In this embodiment, the first filtering branch 14 and the third filtering branch 16 are transmitting filtering branches, and the second filtering branch 15 and the fourth filtering branch 17 are receiving filtering branches.

The first filtering branch 14 is coupled to the first common cavity 12 and is composed of ten filtering cavities coupled in sequence, and the ten filtering cavities of the first filtering branch 14 further form four cross-coupling zeros 141.

And the second filtering branch 15 is coupled with the first common cavity 12 and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the second filtering cavity branch 15 further form three cross-coupling zeros 151.

And the third filtering branch 16 is coupled with the second common cavity 13 and is composed of eleven filtering cavities coupled in sequence, and the eleven filtering cavities of the third filtering branch 16 further form three cross-coupling zeros 161.

And a fourth filtering branch 17, coupled to the second common cavity 13, and composed of eight filtering cavities coupled in sequence, where the eight filtering cavities of the fourth filtering cavity branch 17 further form two cross-coupling zeros 171.

The first filtering cavity A1 of the first filtering branch 14, the first filtering cavity B1 of the second filtering branch 15 and the fifth filtering cavity B5 are respectively intersected with the first common cavity 12; the first filter cavity C1 of the third filter branch 16, the first filter cavity D1 of the fourth filter branch 17 and the second filter cavity D2 are respectively intersected with the second common cavity 13.

Optionally, referring to fig. 1, for example, the intersection of the first filter cavity a1 of the first filter branch 14 and the first common cavity 12 is set as an example, the first filter cavity a1 of the first filter branch 14 intersects with a cavity circle of the first common cavity 12 to form a cavity circle intersection region, the cavity circle intersection region has two end points, a window is disposed in the cavity circle intersection region, so that the first filter cavity a1 forms a window coupling with the first common cavity 12, and the width of the window is equal to the length of a connection line between the two end points. The cavity circles of the two filtering cavities are intersected, and the window is arranged in the intersected area of the cavity circles, so that the distance between the centers of the two filtering cavities can be reduced, the coupling is enhanced, the situation that a separation wall needs to be arranged between the two filtering cavities which are sequentially coupled in the traditional filtering cavity is avoided, then the coupling window is arranged on the separation wall, the materials are reduced, and the processing is convenient.

The number of taps can be reduced by arranging the first common cavity 12 and the second common cavity 13, so that required welding points are reduced, and the size of the filter 10 is reduced; the filter 10 is reduced in size and cost by arranging the first surface 111 and the second surface 112; the zero point suppression can be realized by the cross coupling zero point, so that the indexes are convenient to debug and the design requirements are met; the distance between the centers of the two filtering cavities can be reduced by intersecting the filtering cavities, the coupling is enhanced, the situation that a partition wall needs to be arranged between the two filtering cavities which are sequentially coupled in the traditional filtering cavity is avoided, then a coupling window is formed on the partition wall, the materials are reduced, and the processing is convenient.

The second filtering cavity a2, the third filtering cavity A3, the fourth filtering cavity a4, the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 14 are in a row and are sequentially arranged along the first direction L; the first filtering cavity a1, the fifth filtering cavity a5, the sixth filtering cavity a6 and the ninth filtering cavity a9 of the first filtering branch 14 are in a row and are sequentially arranged along the first direction L; the fifth filtering cavity B5, the sixth filtering cavity B6 and the eighth filtering cavity B8 of the second filtering branch 15 are in a row and are sequentially arranged along the first direction L; the first filtering cavity B1, the fourth filtering cavity B4 and the seventh filtering cavity B7 of the second filtering branch 15 are in a row and are sequentially arranged along the first direction L; the second filter cavity B2 and the third filter cavity B3 of the second filter branch 15 are in a row and are sequentially arranged along the first direction L.

Further, the first filter cavity a1 of the first filter branch 14 is respectively disposed adjacent to the second filter cavity a2, the third filter cavity A3, the fifth filter cavity a5 and the first common cavity 12; the sixth filtering cavity a6 of the first filtering branch 14 is respectively adjacent to the fourth filtering cavity a4, the fifth filtering cavity a5, the seventh filtering cavity a7, the ninth filtering cavity a9, the sixth filtering cavity B6 of the second filtering branch 15 and the eighth filtering cavity B8; the ninth filtering cavity a9 of the first filtering branch 14 is respectively adjacent to the sixth filtering cavity a6, the seventh filtering cavity a7, the eighth filtering cavity A8 and the tenth filtering cavity a 10; the eighth filtering cavity A8 of the first filtering branch 14 is respectively intersected with the seventh filtering cavity a7 and the ninth filtering cavity a 9; the fourth filtering cavity B4 of the second filtering branch 15 is respectively adjacent to the first filtering cavity B1, the third filtering cavity B3, the fifth filtering cavity B5, the sixth filtering cavity B6 and the seventh filtering cavity B7.

The ten filter cavities of the first filter branch 14 are regularly arranged, so that the space in the housing 11 can be saved, the size of the filter 10 can be reduced, and the stability of the filter 10 can be improved. Further, ten filter cavities of the first filter branch 14 have the same size, so that the first filter cavity a1 to the tenth filter cavity a10 of the first filter branch 14 in the housing 11 can be distributed at equal intervals, and the distances between the centers of any two adjacent filter cavities are equal, so that the arrangement is tight, the layout and debugging are facilitated, and the consistency of the filter 10 is improved.

As shown in fig. 2, the first filter cavity a1 and the third filter cavity A3, the fourth filter cavity a4 and the sixth filter cavity a6, and the seventh filter cavity a7 and the ninth filter cavity a9 of the first filter branch 14 are respectively capacitively cross-coupled, and the fourth filter cavity a4 and the seventh filter cavity a7 are inductively cross-coupled to form four cross-coupled zeros 141 of the first filter branch 14, such as capacitors C1, C2, C3, and an inductor L1 shown in fig. 2. The zero point suppression can be realized by setting the cross-coupling zero point 141 of the first filtering branch 14, so that the debugging index is facilitated, and the design requirement is met.

Specifically, a window may be disposed between the first filter cavity a1 and the third filter cavity A3 of the first filter branch 14, and a capacitive fly rod may be disposed at the window, so as to implement capacitive cross coupling between the first filter cavity a1 and the third filter cavity A3, forming a capacitive cross coupling zero, which is equivalent to the capacitor C1. A window may be disposed between the fourth filter cavity a4 and the sixth filter cavity a6 of the first filter branch 14, and a capacitive fly rod is disposed at the window, so that capacitive cross coupling is achieved between the fourth filter cavity a4 and the sixth filter cavity a6, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C2. A window may be disposed between the seventh filter cavity a7 and the ninth filter cavity a9 of the first filter branch 14, and a capacitive fly rod may be disposed at the window, so that capacitive cross coupling is achieved between the seventh filter cavity a7 and the ninth filter cavity a9, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C3. A window may be disposed between the fourth filtering cavity a4 and the seventh filtering cavity a7 of the first filtering branch 14, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is achieved between the fourth filtering cavity a4 and the seventh filtering cavity a7, and an inductive cross coupling zero is formed, which is equivalent to the inductor L1. 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.

As shown in fig. 3, the first filter cavity B1 and the third filter cavity B3, the fourth filter cavity B4 and the sixth filter cavity B6, and the fourth filter cavity B4 and the seventh filter cavity B7 of the second filter branch 15 are inductively cross-coupled to form three cross-coupled zeros 151 of the second filter branch 15, which are respectively shown as inductors L1, L2, and L3 in fig. 3. Wherein, zero point suppression can be realized to the cross coupling zero point 151's of second filtering branch 15 setting, and the debugging index of being convenient for reaches the design requirement, and the setting of pure cross coupling zero point 151 makes wave filter 10 material kind reduce moreover, can reduce the product complexity, and the uniformity of material is good, and product stability is high.

Specifically, a window may be disposed between the first filter cavity B1 and the third filter cavity B3 of the second filter branch 15, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the first filter cavity B1 and the third filter cavity B3, and an inductive cross coupling zero is formed, which is equivalent to the inductance L1. A window may be disposed between the fourth filtering cavity B4 and the sixth filtering cavity B6 of the second filtering branch 15, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the fourth filtering cavity B4 and the sixth filtering cavity B6, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L2. A window may be disposed between the fourth filtering cavity B4 and the seventh filtering cavity B7 of the second filtering branch 15, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is achieved between the fourth filtering cavity B4 and the seventh filtering cavity B7, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L3. 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 fourth filtering cavity C4 to the eighth filtering cavity C8 of the third filtering branch 16 are arranged in a W shape; the first filtering cavity C1 to the fourth filtering cavity C4 of the third filtering branch 16 are quadrilateral, the projection of the center of the first filtering cavity C1 and the center of the third filtering cavity C3 in the first direction L is located between the center of the second filtering cavity C2 and the projection of the center of the fourth filtering cavity C4 in the first direction L, and the projection of the center of the second filtering cavity C2 and the center of the fourth filtering cavity C4 in the second direction D is located between the center of the first filtering cavity C1 and the projection of the center of the third filtering cavity C3 in the second direction D; the eighth filtering cavity C8 and the ninth filtering cavity C9 of the third filtering branch 16 are in a row and are sequentially arranged along the first direction L; the first filter cavity D1 and the third filter cavity D3 of the fourth filter branch 17 are in a row and are sequentially arranged along the first direction L; the second filtering cavity D2 to the fifth filtering cavity D5 of the fourth filtering branch 17 are quadrilateral, the projection of the center of the third filtering cavity D3 and the center of the fourth filtering cavity D4 in the first direction L is located between the center of the second filtering cavity D2 and the projection of the center of the fifth filtering cavity D5 in the first direction L, and the projection of the center of the second filtering cavity D2 and the center of the fourth filtering cavity D4 in the second direction D is located between the center of the first filtering cavity D1 and the projection of the center of the third filtering cavity D3 in the second direction D; the fifth filtering cavity D5 to the seventh filtering cavity D7 of the fourth filtering branch 17 are arranged in a triangle, the projection of the center of the sixth filtering cavity D6 in the first direction L is located between the center of the fifth filtering cavity D5 and the projection of the center of the seventh filtering cavity D7 in the first direction L, and the projection of the center of the seventh filtering cavity D7 in the second direction D is located between the center of the fifth filtering cavity D5 and the projection of the center of the sixth filtering cavity D6 in the second direction D.

Further, the first filtering cavity C1 of the third filtering branch 16 is respectively disposed adjacent to the second filtering cavity C2, the third filtering cavity C3, the fourth filtering cavity C4, the fifth filtering cavity C5 and the second common cavity 13; the seventh filtering cavity C7 of the third filtering branch 16 is respectively adjacent to the fifth filtering cavity C5, the sixth filtering cavity C6, the eighth filtering cavity C8, the tenth filtering cavity C10, the fourth filtering cavity D4 of the fourth filtering branch 17 and the sixth filtering cavity D6; the seventh filter cavity D7 of the fourth filter branch 17 is respectively adjacent to the eighth filter cavity D8, the sixth filter cavity D6 and the eleventh filter cavity C11 of the third filter branch 16; the second filtering cavity D2 of the fourth filtering branch 17 is respectively adjacent to the first filtering cavity D1, the third filtering cavity D3, the fourth filtering cavity D4, the fifth filtering cavity C5 of the third filtering branch 16 and the second common cavity 13.

As shown in fig. 4, capacitive cross coupling is performed between the fourth filter cavity C4 and the sixth filter cavity C6, between the eighth filter cavity C8 and the tenth filter cavity C10, and inductive cross coupling is performed between the sixth filter cavity C6 and the eighth filter cavity C8 of the third filter branch 16, so as to form three cross-coupling zeros 161 of the third filter branch 16, such as a capacitor C1, a capacitor C2, and an inductor L1, which are shown in fig. 4. The zero point suppression can be realized by setting the cross-coupling zero point 161 of the third filtering branch 16, so that the debugging index is facilitated, and the design requirement is met.

Specifically, a window may be disposed between the fourth filter cavity C4 and the sixth filter cavity C6 of the third filter branch 16, and a capacitive fly rod is disposed at the window, so that capacitive cross coupling is achieved between the fourth filter cavity C4 and the sixth filter cavity C6, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C1. A window may be disposed between the eighth filtering cavity C8 and the tenth filtering cavity C10 of the third filtering branch 16, and a capacitive flying bar is disposed at the window, so that capacitive cross coupling is achieved between the eighth filtering cavity C8 and the tenth filtering cavity C10, and a capacitive cross coupling zero point is formed, which is equivalent to the capacitor C2. A window may be disposed between the sixth filtering cavity C6 and the eighth filtering cavity C8 of the third filtering branch 16, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity C6 and the eighth filtering cavity C8 realize inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L1. 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.

As shown in fig. 5, the first filter cavity D1 and the third filter cavity D3 of the fourth filter branch 17 and the fourth filter cavity D4 and the sixth filter cavity D6 are capacitively cross-coupled to form two cross-coupling zeros 171 of the fourth filter branch 17, such as capacitors C1 and C2 shown in fig. 5, respectively. The zero point suppression can be realized by the arrangement of the cross coupling zero point 171 of the fourth filtering branch 17, so that the debugging index is convenient, the design requirement is met, the material types of the filter 10 are reduced by the arrangement of the pure capacitive cross coupling zero point 171, the product complexity can be reduced, the material consistency is good, and the product stability is high.

Specifically, a window may be disposed between the first filter cavity D1 and the third filter cavity D3 of the fourth filter branch 17, and a capacitive fly rod is disposed at the window, so that capacitive cross coupling is achieved between the first filter cavity D1 and the third filter cavity D3, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C1. A window may be disposed between the fourth filter cavity D4 and the sixth filter cavity D6 of the fourth filter branch 17, and a capacitive flying bar is disposed at the window, so that capacitive cross coupling is achieved between the fourth filter cavity D4 and the sixth filter cavity D6, a capacitive cross coupling zero is formed, and the capacitive cross coupling zero is equivalent to the capacitor C2.

The coupling zero is also referred to as a transmission zero. The transmission zero is the transmission function of the filter 10 equal to zero, that is, the electromagnetic energy cannot pass through the network at the frequency point corresponding to the transmission zero, so that the complete isolation effect is achieved, the inhibition effect on signals outside the band-pass is achieved, and the high isolation among a plurality of band-passes can be better achieved.

In the present embodiment, the first common cavity 12 and the second common cavity 13 can reduce the number of taps, reduce the required welding points, and reduce the size of the filter 10; the filter 10 is reduced in size and cost by arranging the first surface 111 and the second surface 112; the zero point suppression can be realized by the cross coupling zero point, so that the indexes are convenient to debug and the design requirements are met; the distance between the centers of the two filter cavities can be reduced by intersecting the filter cavities, the coupling is enhanced, a partition wall is prevented from being required to be arranged between the two filter cavities which are sequentially coupled in the traditional filter cavity, and then a coupling window is arranged on the partition wall, so that the material is reduced, and the processing is convenient; zero point suppression can be realized by setting the cross coupling zero point 141 of the first filtering branch 14, the cross coupling zero point 151 of the second filtering branch 15, the cross coupling zero point 161 of the third filtering branch 16 and the cross coupling zero point 171 of the fourth filtering branch 17, so that the debugging index is convenient, and the design requirement is met; 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.

Referring to fig. 6, fig. 6 is a schematic structural diagram of another embodiment of the filter of the present application. The filter 10 of the present embodiment further includes a third common cavity 22, a fifth filtering branch 24 and a sixth filtering branch 25 disposed on the first surface 111, and a fourth common cavity 23, a seventh filtering branch 26 and an eighth filtering branch 27 disposed on the second surface 112, based on the embodiment shown in fig. 1.

In this embodiment, the fifth filtering branch 24 and the seventh filtering branch 26 are transmitting filtering branches, and the sixth filtering branch 25 and the eighth filtering branch 27 are receiving filtering branches.

And a fifth filtering branch 24, coupled to the third common cavity 22, and composed of ten filtering cavities coupled in sequence, where the ten filtering cavities of the fifth filtering branch 24 further form four cross-coupling zeros 241.

And a sixth filtering branch 25, coupled to the third common cavity 22, and composed of eight filtering cavities coupled in sequence, where the eight filtering cavities of the sixth filtering cavity branch 25 further form three cross-coupling zeros 251.

And the seventh filtering branch 26 is coupled with the fourth common cavity 23 and is composed of eleven filtering cavities coupled in sequence, and the eleven filtering cavities of the seventh filtering branch 26 further form three cross-coupling zeros 261.

And an eighth filtering branch 27, coupled to the fourth common cavity 23, and composed of eight filtering cavities coupled in sequence, where the eight filtering cavities of the eighth filtering cavity branch 27 further form two cross-coupling zeros 271.

The first filter cavity E1 of the fifth filter branch 24 intersects with the third common cavity 22, and the first filter cavity G1 of the seventh filter branch 26 intersects with the fourth common cavity 23.

The first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 24 are in a row and are sequentially arranged along the second direction D; the fourth filter cavity E4 and the third filter cavity E3 of the fifth filter branch 24 are in a row and are sequentially arranged along the second direction D; the fifth filter cavity E5, the eighth filter cavity E8 and the ninth filter cavity E9 of the fifth filter branch 24 are in a row and are sequentially arranged along the second direction D; the sixth filtering cavity E6, the seventh filtering cavity E7 and the tenth filtering cavity E10 of the fifth filtering branch 24 are in a row and are sequentially arranged along the second direction D; the first filter cavity F1 to the fourth filter cavity F4 of the sixth filter branch 25 are arranged in a quadrilateral shape, the projection of the center of the first filter cavity F1 and the center of the second filter cavity F2 in the first direction L is positioned between the center of the third filter cavity F3 and the projection of the center of the fourth filter cavity F4 in the first direction L, and the projection of the center of the second filter cavity F2 and the center of the fourth filter cavity F4 in the second direction D is positioned between the center of the third filter cavity F3 and the projection of the center of the first filter cavity F1 in the second direction D; the fourth filter cavity F4, the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 25 are in a row and are sequentially arranged along the first direction L; the sixth filtering cavity F6 to the eighth filtering cavity F8 of the sixth filtering branch 25 are arranged in a triangle, the projection of the center of the sixth filtering cavity F6 in the first direction L is located between the center of the seventh filtering cavity F7 and the projection of the center of the eighth filtering cavity F8 in the first direction L, and the projection of the center of the eighth filtering cavity F8 in the second direction D is located between the center of the seventh filtering cavity F7 and the projection of the center of the sixth filtering cavity F6 in the second direction D; the second filter cavity B2, the third filter cavity B3 of the second filter branch 15 and the seventh filter cavity F7 of the sixth filter branch 25 are in a row and are sequentially arranged along the first direction L.

Further, the fourth filtering cavity F4 of the sixth filtering branch 25 is respectively disposed adjacent to the first filtering cavity F1, the second filtering cavity F2, the third filtering cavity F3, the fifth filtering cavity F5 and the second filtering cavity B2 of the second filtering branch 15; the sixth filtering cavity F6 of the sixth filtering branch 25 is respectively adjacent to the fifth filtering cavity F5, the seventh filtering cavity F7, the eighth filtering cavity F8 and the fourth filtering cavity E4 of the fifth filtering branch 24; the first filter cavity E1 of the fifth filter branch 24 is respectively adjacent to the second filter cavity E2, the third filter cavity E3, the fourth filter cavity E4 and the third common cavity 22; the ninth filter cavity E9 of the fifth filter branch 24 is respectively adjacent to the third filter cavity E3, the eighth filter cavity E8 and the tenth filter cavity E10; the fifth filter cavity E5 of the fifth filter branch 24 is respectively adjacent to the fourth filter cavity E4, the sixth filter cavity E6, the seventh filter cavity E7, the eighth filter cavity E8 and the eighth filter cavity F8 of the sixth filter branch 25.

As shown in fig. 7, the first filter cavity E1 and the third filter cavity E3, the fifth filter cavity E5 and the seventh filter cavity E7, and the eighth filter cavity E8 and the tenth filter cavity E10 of the fifth filter branch 24 are respectively capacitively cross-coupled, and the seventh filter cavity E7 and the tenth filter cavity E10 are inductively cross-coupled to form four cross-coupled zeros 241 of the fifth filter branch 24, such as capacitors C1, C2, C3, and an inductor L1 shown in fig. 7. The zero point suppression can be realized by setting the cross-coupling zero point 241 of the fifth filtering branch 24, so that the debugging index is facilitated, and the design requirement is met.

Specifically, a window may be disposed between the first filter cavity E1 and the third filter cavity E3 of the fifth filter branch 24, and a capacitive fly rod is disposed at the window, so that capacitive cross coupling is achieved between the first filter cavity E1 and the third filter cavity E3, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C1. A window may be disposed between the fifth filter cavity E5 and the seventh filter cavity E7 of the fifth filter branch 24, and a capacitive flying bar is disposed at the window, so that capacitive cross coupling is achieved between the fifth filter cavity E5 and the seventh filter cavity E7, a capacitive cross coupling zero is formed, and the capacitive cross coupling zero is equivalent to the capacitor C2. A window may be disposed between the eighth filtering cavity E8 and the tenth filtering cavity E10 of the fifth filtering branch 24, and a capacitive flying bar is disposed at the window, so that capacitive cross coupling is achieved between the eighth filtering cavity E8 and the tenth filtering cavity E10, and a capacitive cross coupling zero point is formed, which is equivalent to the capacitor C3. A window may be disposed between the seventh filtering cavity E7 and the tenth filtering cavity E10 of the fifth filtering branch 24, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the seventh filtering cavity E7 and the tenth filtering cavity E10, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L1. 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.

As shown in fig. 8, the first filter cavity F1 and the fourth filter cavity F4, the second filter cavity F2 and the fourth filter cavity F4, and the sixth filter cavity F6 and the eighth filter cavity F8 of the sixth filter branch 25 are inductively cross-coupled to form three cross-coupled zeros 251 of the sixth filter branch 25, which are respectively inductors L1, L2, and L3 shown in fig. 8. The zero point suppression can be realized by the arrangement of the cross coupling zero point 251 of the sixth filtering branch 25, so that the debugging index is convenient, the design requirement is met, the material types of the filter 10 are reduced by the arrangement of the pure cross coupling zero point 251, the product complexity can be reduced, the material consistency is good, and the product stability is high.

Specifically, a window may be disposed between the first filter cavity F1 and the fourth filter cavity F4 of the sixth filter branch 25, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the first filter cavity F1 and the fourth filter cavity F4, and an inductive cross coupling zero is formed, which is equivalent to the inductance L1. A window may be disposed between the second filter cavity F2 and the fourth filter cavity F4 of the sixth filter branch 25, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the second filter cavity F2 and the fourth filter cavity F4, and an inductive cross coupling zero is formed, which is equivalent to the inductor L2. A window may be disposed between the sixth filtering cavity F6 and the eighth filtering cavity F8 of the sixth filtering branch 25, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity F6 and the eighth filtering cavity F8 realize inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L3. 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 third filtering cavity G3, the fourth filtering cavity G4 and the fifth filtering cavity G5 of the seventh filtering branch 26 are in a row and are sequentially arranged along the first direction L; the second filtering cavity G2 and the sixth filtering cavity G6 of the seventh filtering branch 26 are in a row and are sequentially arranged along the first direction L; the first filtering cavity G1, the seventh filtering cavity G7 and the eighth filtering cavity G8 of the seventh filtering branch 26 are in a row and are sequentially arranged along the first direction L; the eighth filtering cavity G8 to the tenth filtering cavity G10 of the seventh filtering branch 26 are arranged in a triangle, the projection of the center of the ninth filtering cavity G9 in the first direction L is located between the center of the eighth filtering cavity G8 and the projection of the center of the tenth filtering cavity G10 in the first direction L, and the projection of the center of the eighth filtering cavity G8 in the second direction D is located between the center of the ninth filtering cavity G9 and the projection of the center of the tenth filtering cavity G10 in the second direction D; the eleventh filtering cavity G11 of the seventh filtering branch 26 intersects the tenth filtering cavity G10; the first filter cavity H1 and the fourth filter cavity H4 of the eighth filter branch 27 are arranged in a diamond shape, the projection of the center of the first filter cavity H1 and the center of the fourth filter cavity H4 in the first direction L is located between the projection of the center of the second filter cavity H2 and the projection of the center of the third filter cavity H3 in the first direction L, and the projection of the center of the second filter cavity H2 and the projection of the center of the third filter cavity H3 in the second direction D is located between the projection of the center of the first filter cavity H1 and the projection of the center of the fourth filter cavity H4 in the second direction D; the fourth filter cavity H4 through the eighth filter cavity H8 of the eighth filter branch 27 are sequentially arranged in the first direction L.

Further, the third filter cavity H3 of the eighth filter branch 27 is respectively disposed adjacent to the first filter cavity H1, the second filter cavity H2 and the fourth filter cavity H4; the fifth filtering cavity H5 of the eighth filtering branch 27 is respectively adjacent to the fourth filtering cavity H4, the sixth filtering cavity H6, the first filtering cavity G1 of the seventh filtering branch 26 and the first filtering cavity D1 of the fourth filtering branch 17; the eighth filtering cavity H8 of the eighth filtering branch 27 is respectively adjacent to the seventh filtering cavity H7, the eighth filtering cavity G8 of the seventh filtering branch 26, the ninth filtering cavity G9 and the fifth filtering cavity D5 of the fourth filtering branch 17; the second filtering cavity G2 of the seventh filtering branch 26 is respectively adjacent to the first filtering cavity G1, the third filtering cavity G3, the fourth filtering cavity G4, the sixth filtering cavity G6 and the seventh filtering cavity G7; the eleventh filtering cavity G11 of the seventh filtering branch 26 is respectively adjacent to the tenth filtering cavity G10 and the fifth filtering cavity G5; the eighth filtering cavity G8 of the seventh filtering branch 26 is respectively adjacent to the sixth filtering cavity G6, the seventh filtering cavity G7, the ninth filtering cavity G9, the tenth filtering cavity G10 and the eighth filtering cavity H8 of the eighth filtering branch 27.

As shown in fig. 9, the fourth filtering cavity G4 and the sixth filtering cavity G6, the eighth filtering cavity G8 and the tenth filtering cavity G10 of the seventh filtering branch 26 are inductively cross-coupled, and the sixth filtering cavity G6 and the eighth filtering cavity G8 are capacitively cross-coupled, so as to form three cross-coupled zeros 261 of the seventh filtering branch 26, such as the inductors L1, L2 and the capacitor C1 shown in fig. 9. The zero point suppression can be realized by setting the cross-coupling zero point 261 of the seventh filtering branch 26, so that the debugging index is facilitated, and the design requirement is met.

Specifically, a window may be disposed between the fourth filtering cavity G4 and the sixth filtering cavity G6 of the seventh filtering branch 26, and a metal coupling rib is disposed on the window, so that the inductive cross-coupling is implemented between the fourth filtering cavity G4 and the sixth filtering cavity G6, and an inductive cross-coupling zero is formed, which is equivalent to the inductor L1. A window may be disposed between the eighth filtering cavity G8 and the tenth filtering cavity G10 of the seventh filtering branch 26, and a metal coupling rib is disposed on the window, so that the eighth filtering cavity G8 and the tenth filtering cavity G10 realize inductive cross coupling, and an inductive cross coupling zero point is formed, which is equivalent to the inductor L2. A window may be disposed between the fifth filtering cavity G5 and the eighth filtering cavity G8 of the seventh filtering branch 26, and a capacitive flying bar is disposed at the window, so that capacitive cross coupling is achieved between the fifth filtering cavity G5 and the eighth filtering cavity G8, a capacitive cross coupling zero is formed, and the capacitive cross coupling zero is equivalent to the capacitor C1. 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.

As shown in fig. 10, the second filter cavity H2 of the eighth filter branch 27 is capacitively cross-coupled with the fourth filter cavity H4, and the second filter cavity H2 is inductively cross-coupled with the fifth filter cavity H5, so as to form two cross-coupling zeros 271 of the eighth filter branch 27, such as the capacitor C1 and the inductor L1 shown in fig. 10. The setting of the cross-coupling zero 271 of the eighth filtering branch 27 can realize zero suppression, thereby facilitating the debugging of indexes and achieving design requirements.

Specifically, a window may be disposed between the second filtering cavity H2 and the fourth filtering cavity H4 of the eighth filtering branch 27, and a capacitive fly rod is disposed at the window, so that capacitive cross coupling is achieved between the second filtering cavity H2 and the fourth filtering cavity H4, and a capacitive cross coupling zero is formed, which is equivalent to the capacitor C1. A window may be disposed between the second filtering cavity H2 and the fifth filtering cavity H5 of the eighth filtering branch 27, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is implemented between the second filtering cavity H2 and the fifth filtering cavity H5, and an inductive cross coupling zero is formed, which is equivalent to the inductor L1.

Optionally, the housing 11 is further provided with a first port (not shown), a second port (not shown), a third port (not shown), a fourth port (not shown), a fifth port (not shown), a sixth port (not shown), a seventh port (not shown), an eighth port (not shown), a ninth port (not shown), a tenth port (not shown), an eleventh port (not shown), and a twelfth port (not shown).

The first common cavity 12 is connected to the first port, the tenth filtering cavity a10 of the first filtering branch 14 is connected to the second port, and the eighth filtering cavity B8 of the second filtering branch 15 is connected to the third port; the second common cavity 13 is connected with the fourth port, the eleventh filtering cavity C11 of the third filtering branch 16 is connected with the fifth port, and the eighth filtering cavity D8 of the fourth filtering branch 17 is connected with the sixth port; the third common cavity 22 is connected to the seventh port, the tenth filtering cavity E10 of the fifth filtering branch 24 is connected to the eighth port, and the eighth filtering cavity F8 of the sixth filtering branch 25 is connected to the ninth port; the fourth common cavity 23 is connected to the tenth port, the eleventh filtering cavity G11 of the seventh filtering branch 26 is connected to the eleventh port, and the eighth filtering cavity H8 of the eighth filtering branch 27 is connected to the twelfth port.

The first to twelfth ports may be taps of the filter 10.

The bandwidth of the first filtering branch 14 of this embodiment lies in the range 919Mhz-962 Mhz. In particular, the coupling bandwidth between the first common cavity 12 and the first filter cavity a1 of the first filter branch 14 ranges from 35Mhz to 44 Mhz; the coupling bandwidth between the first filter cavity a1 and the second filter cavity a2 of the first filter branch 14 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the first filter cavity a1 and the third filter cavity A3 of the first filter branch 14 ranges from-15 Mhz-9 Mhz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 14 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 14 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 14 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fourth filter cavity a4 and the sixth filter cavity a6 of the first filter branch 14 ranges from-17 Mhz to-11 Mhz; the coupling bandwidth between the fourth filter cavity a4 and the seventh filter cavity a7 of the first filter branch 14 ranges from 0Mhz to 5 Mhz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 14 ranges from 8Mhz to 14 Mhz; the coupling bandwidth between the sixth filter cavity a6 and the seventh filter cavity a7 of the first filter branch 14 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the seventh filter cavity a7 and the eighth filter cavity A8 of the first filter branch 14 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the seventh filter cavity a7 and the ninth filter cavity a9 of the first filter branch 14 ranges from-12 Mhz to-7 Mhz; the coupling bandwidth between the eighth filter cavity A8 and the ninth filter cavity a9 of the first filter branch 14 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the ninth filter cavity a9 and the tenth filter cavity a10 of the first filter branch 14 ranges from 28Mhz to 36 Mhz; the coupling bandwidth between the tenth filter cavity a10 of the first filter branch 14 and the second port is in the range of 35Mhz-44 Mhz.

The bandwidth of the second filtering branch 15 of this embodiment is in the range of 878Mhz-919 Mhz. In particular, the coupling bandwidth between the first common cavity 12 and the first filter cavity B1 of the second filter branch 15 ranges from 34Mhz to 42 Mhz; the coupling bandwidth between the first filter cavity B1 and the second filter cavity B2 of the second filter branch 15 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the first filter cavity B1 and the third filter cavity B3 of the second filter branch 15 ranges from 7Mhz to 13 Mhz; the coupling bandwidth between the second filter cavity B2 and the third filter cavity B3 of the second filter branch 15 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the third filter cavity B3 and the fourth filter cavity B4 of the second filter branch 15 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the fourth filter cavity B4 and the fifth filter cavity B5 of the second filter branch 15 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fourth filter cavity B4 and the sixth filter cavity B6 of the second filter branch 15 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fourth filter cavity B4 and the seventh filter cavity B7 of the second filter branch 15 ranges from 0Mhz to 5 Mhz; the coupling bandwidth between the fifth filter cavity B5 and the sixth filter cavity B6 of the second filter branch 15 ranges from 9Mhz to 15 Mhz; the coupling bandwidth between the sixth filter cavity B6 and the seventh filter cavity B7 of the second filter branch 15 ranges from 18Mhz to 25 Mhz; the coupling bandwidth between the seventh filter cavity B7 and the eighth filter cavity B8 of the second filter branch 15 ranges from 27Mhz to 35 Mhz; the coupling bandwidth between the eighth filter cavity B8 of the second filter branch 15 and the third port is in the range of 34Mhz-42 Mhz.

The bandwidth of the third filtering branch 16 of this embodiment lies in the range 789Mhz-824 Mhz. In particular, the coupling bandwidth between the second common cavity 13 and the first filter cavity C1 of the third filter branch 16 ranges from 27Mhz to 35 Mhz; the coupling bandwidth between the first filter cavity C1 and the second filter cavity C2 of the third filter branch 16 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the second filter cavity C2 and the third filter cavity C3 of the third filter branch 16 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity C3 and the fourth filter cavity C4 of the third filter branch 16 ranges from 13Mhz to 19 Mhz; the coupling bandwidth between the fourth filter cavity C4 and the fifth filter cavity C5 of the third filter branch 16 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fourth filter cavity C4 and the sixth filter cavity C6 of the third filter branch 16 ranges from 4Mhz to 9 Mhz; the coupling bandwidth between the fifth filter cavity C5 and the sixth filter cavity C6 of the third filter branch 16 ranges from 12Mhz to 18 Mhz; the coupling bandwidth between the sixth filter cavity C6 and the seventh filter cavity C7 of the third filter branch 16 ranges from 6Mhz to 11 Mhz; the coupling bandwidth between the sixth filter cavity C6 and the eighth filter cavity C8 of the third filter branch 16 ranges from-15 Mhz to-9 Mhz; the coupling bandwidth between the seventh filter cavity C7 and the eighth filter cavity C8 of the third filter branch 16 ranges from 7Mhz to 12 Mhz; the coupling bandwidth between the eighth filter cavity C8 and the ninth filter cavity C9 of the third filter branch 16 ranges from 12Mhz to 18 Mhz; the coupling bandwidth between the eighth filter cavity C8 and the tenth filter cavity C10 of the third filter branch 16 ranges from 4Mhz to 9 Mhz; the coupling bandwidth between the ninth filter cavity C9 and the tenth filter cavity C10 of the third filter branch 16 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the tenth filter cavity C10 and the eleventh filter cavity C11 of the third filter branch 16 ranges from 22Mhz to 29 Mhz; the coupling bandwidth between the eleventh filter cavity C11 and the fifth port of the third filter branch 16 is in the range of 27Mhz-35 Mhz.

The bandwidth of the fourth filtering branch 17 of this embodiment is in the range 826Mhz-865 Mhz. In particular, the coupling bandwidth between the second common cavity 13 and the first filter cavity D1 of the fourth filter branch 17 ranges from 32Mhz to 40 Mhz; the coupling bandwidth between the first filter cavity D1 and the second filter cavity D2 of the fourth filter branch 17 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the first filter cavity D1 and the third filter cavity D3 of the fourth filter branch 17 ranges from-14 Mhz to-8 Mhz; the coupling bandwidth between the second filter cavity D2 and the third filter cavity D3 of the fourth filter branch 17 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity D3 and the fourth filter cavity D4 of the fourth filter branch 17 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the fourth filter cavity D4 and the fifth filter cavity D5 of the fourth filter branch 17 ranges from 13Mhz to 19 Mhz; the coupling bandwidth between the fourth filter cavity D4 and the sixth filter cavity D6 of the fourth filter branch 17 ranges from-11 Mhz to-6 Mhz; the coupling bandwidth between the fifth filter cavity D5 and the sixth filter cavity D6 of the fourth filter branch 17 ranges from 13Mhz to 19 Mhz; the coupling bandwidth between the sixth filter cavity D6 and the seventh filter cavity D7 of the fourth filter branch 17 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the seventh filter cavity D7 and the eighth filter cavity D8 of the fourth filter branch 17 ranges from 15Mhz to 33 Mhz; the coupling bandwidth between the eighth filter cavity D8 and the sixth port of the fourth filter branch 17 is in the range of 32Mhz-40 Mhz.

The bandwidth of the fifth filtering branch 24 of this embodiment lies in the range 919Mhz-962 Mhz. In particular, the coupling bandwidth between the third common cavity 22 and the first filter cavity E1 of the fifth filter branch 24 ranges from 35Mhz to 44 Mhz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 24 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the first filter cavity E1 and the third filter cavity E3 of the fifth filter branch 24 ranges from-16 Mhz to-10 Mhz; the coupling bandwidth between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch 24 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch 24 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 24 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch 24 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the fifth filter cavity E5 and the seventh filter cavity E7 of the fifth filter branch 24 ranges from-10 Mhz to-5 Mhz; the coupling bandwidth between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch 24 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch 24 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the seventh filter cavity E7 and the tenth filter cavity E10 of the fifth filter branch 24 ranges from 3Mhz to 8 Mhz; the coupling bandwidth between the eighth filter cavity E8 and the ninth filter cavity E9 of the fifth filter branch 24 ranges from 7Mhz to 12 Mhz; the coupling bandwidth between the eighth filter cavity E8 and the tenth filter cavity E10 of the fifth filter branch 24 ranges from-27 Mhz to-20 Mhz; the coupling bandwidth between the ninth filter cavity E9 and the tenth filter cavity E10 of the fifth filter branch 24 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the tenth filter cavity E10 and the eighth port of the fifth filter branch 24 is in the range of 35Mhz-44 Mhz.

The bandwidth of the sixth filtering branch 25 of this embodiment is in the range of 878Mhz-919 Mhz. In particular, the coupling bandwidth between the third common cavity 22 and the first filter cavity F1 of the sixth filter branch 25 ranges from 34Mhz to 42 Mhz; the coupling bandwidth between the first filter cavity F1 and the second filter cavity F2 of the sixth filter branch 25 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the first filter cavity F1 and the fourth filter cavity F4 of the sixth filter branch 25 ranges from 1Mhz to 6 Mhz; the coupling bandwidth between the second filter cavity F2 and the third filter cavity F3 of the sixth filter branch 25 ranges from 8Mhz to 14 Mhz; the coupling bandwidth between the second filter cavity F2 and the fourth filter cavity F4 of the sixth filter branch 25 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the third filter cavity F3 and the fourth filter cavity F4 of the sixth filter branch 25 ranges from 10Mhz to 16 Mhz; the coupling bandwidth between the fourth filter cavity F4 and the fifth filter cavity F5 of the sixth filter branch 25 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 25 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the sixth filter cavity F6 and the seventh filter cavity F7 of the sixth filter branch 25 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the sixth filter cavity F6 and the eighth filter cavity F8 of the sixth filter branch 25 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the seventh filter cavity F7 and the eighth filter cavity F8 of the sixth filter branch 25 ranges from 24Mhz to 31 Mhz; the coupling bandwidth between the eighth filter cavity F8 and the ninth port of the sixth filter branch 25 is in the range of 24Mhz-31 Mhz.

The bandwidth of the seventh filtering branch 26 of this embodiment is in the range of 789Mhz-824 Mhz. In particular, the coupling bandwidth between the fourth common cavity 23 and the first filtering cavity G1 of the seventh filtering branch 26 ranges from 27Mhz to 35 Mhz; the coupling bandwidth between the first filter cavity G1 and the second filter cavity G2 of the seventh filter branch 26 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the second filter cavity G2 and the third filter cavity G3 of the seventh filter branch 26 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity G3 and the fourth filter cavity G4 of the seventh filter branch 26 ranges from 13Mhz to 19 Mhz; the coupling bandwidth between the fourth filter cavity G4 and the fifth filter cavity G5 of the seventh filter branch 26 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fourth filter cavity G4 and the sixth filter cavity G6 of the seventh filter branch 26 ranges from 4Mhz to 9 Mhz; the coupling bandwidth between the fifth filter cavity G5 and the sixth filter cavity G6 of the seventh filter branch 26 ranges from 12Mhz to 18 Mhz; the coupling bandwidth between the sixth filter cavity G6 and the seventh filter cavity G7 of the seventh filter branch 26 ranges from 6Mhz to 11 Mhz; the coupling bandwidth between the sixth filter cavity G6 and the eighth filter cavity G8 of the seventh filter branch 26 ranges from-15 Mhz to-9 Mhz; the coupling bandwidth between the seventh filtering cavity G7 and the eighth filtering cavity G8 of the seventh filtering branch 26 ranges from 7Mhz to 12 Mhz; the coupling bandwidth between the eighth filter cavity G8 and the ninth filter cavity G9 of the seventh filter branch 26 ranges from 12Mhz to 18 Mhz; the coupling bandwidth between the eighth filter cavity G8 and the tenth filter cavity G10 of the seventh filter branch 26 ranges from 4Mhz to 9 Mhz; the coupling bandwidth between the ninth filtering cavity G9 and the tenth filtering cavity G10 of the seventh filtering branch 26 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the tenth filter cavity G10 and the eleventh filter cavity G11 of the seventh filter branch 26 ranges from 22Mhz to 29 Mhz; the coupling bandwidth between the eleventh filter cavity G11 and the eleventh port of the seventh filter branch 26 is in the range of 22Mhz-29 Mhz.

The bandwidth of the eighth filtering branch 27 of this embodiment is in the range 826Mhz-865 Mhz. In particular, the coupling bandwidth between the fourth common cavity 23 and the first filtering cavity H1 of the eighth filtering branch 27 ranges from 32Mhz to 40 Mhz; the coupling bandwidth between the first filter cavity H1 and the second filter cavity H2 of the eighth filter branch 27 ranges from 20Mhz to 27 Mhz; the coupling bandwidth between the second filter cavity H2 and the third filter cavity H3 of the eighth filter branch 27 is in the range of 10Mhz to 16 Mhz; the coupling bandwidth between the second filter cavity H2 and the fourth filter cavity H4 of the eighth filter branch 27 ranges from-17 Mhz to-11 Mhz; the coupling bandwidth between the second filter cavity H2 and the fifth filter cavity H5 of the eighth filter branch 27 is in the range of 1Mhz-6 Mhz; the coupling bandwidth between the third filter cavity H3 and the fourth filter cavity H4 of the eighth filter branch 27 is in the range of 7Mhz-12 Mhz; the coupling bandwidth between the fourth filter cavity H4 and the fifth filter cavity H5 of the eighth filter branch 27 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the fifth filter cavity H5 and the sixth filter cavity H6 of the eighth filter branch 27 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the sixth filter cavity H6 and the seventh filter cavity H7 of the eighth filter branch 27 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the seventh filter cavity H7 and the eighth filter cavity H8 of the eighth filter branch 27 ranges from 25Mhz to 33 Mhz; the coupling bandwidth between the eighth filter cavity H8 and the twelfth port of the eighth filtering branch 27 is in the range of 32Mhz-40 Mhz.

Therefore, the resonant frequencies of the first filter cavity a1 through the tenth filter cavity a10 of the first filter branch 14 are sequentially located in the following ranges: 941Mhz-943Mhz, 929Mhz-931Mhz, 941Mhz-943Mhz, 940Mhz-942Mhz, 924Mhz-926Mhz, 937Mhz-939Mhz, 940Mhz-942Mhz, 929Mhz-931Mhz, 939Mhz-941Mhz, 938Mhz-940 Mhz.

The resonant frequencies of the first filter cavity B1 through the eighth filter cavity B8 of the second filter branch 15 are sequentially in the following ranges: 899Mhz-901Mhz, 907Mhz-909Mhz, 896Mhz-898Mhz, 911Mhz-913Mhz, 898Mhz-900Mhz, 896Mhz-898Mhz, and 896Mhz-898 Mhz.

The resonant frequencies of the first filter cavity C1 through the eleventh filter cavity C11 of the third filter branch 16 are sequentially in the following ranges: 803Mhz-805Mhz, 804Mhz-806Mhz, 805Mhz-807Mhz, 812Mhz-814Mhz, 805Mhz-807Mhz, 792Mhz-794Mhz, 805Mhz-807Mhz, 812Mhz-814Mhz, 805Mhz-807Mhz, 806Mhz-808 Mhz.

The resonant frequencies of the first filter cavity D1 through the eighth filter cavity D8 of the fourth filter branch 17 are sequentially in the following ranges: 842Mhz-844Mhz, 834Mhz-836Mhz, 846Mhz-848Mhz, 836Mhz-838Mhz, 846Mhz-848Mhz, 845Mhz-847 Mhz.

The resonant frequencies of the first filter cavity E1 through the tenth filter cavity E10 of the fifth filter branch 24 are in the following ranges in sequence: 940Mhz-942Mhz, 927Mhz-929Mhz, 941Mhz-943Mhz, 940Mhz-942Mhz, 931Mhz-933Mhz, 940Mhz-942Mhz, 938Mhz-940Mhz, 923Mhz-925Mhz, 940Mhz-942 Mhz.

The resonant frequencies of the first filter cavity F1 through the eighth filter cavity F8 of the sixth filter branch 25 are sequentially in the following ranges: 899Mhz-901Mhz, 911Mhz-913Mhz, 895Mhz-897Mhz, 896Mhz-898Mhz, 894Mhz-896Mhz, 907Mhz-909Mhz, and 897Mhz-899 Mhz.

The resonant frequencies of the first filter cavity G1 through the eleventh filter cavity G11 of the seventh filter branch 26 are sequentially in the following ranges: 803Mhz-805Mhz, 804Mhz-806Mhz, 805Mhz-807Mhz, 812Mhz-814Mhz, 805Mhz-807Mhz, 792Mhz-794Mhz, 805Mhz-807Mhz, 812Mhz-814Mhz, 805Mhz-807Mhz, 806Mhz-808 Mhz.

The resonant frequencies of the first filter cavity H1 through the eighth filter cavity H8 of the eighth filter branch 27 are sequentially in the following ranges: 843Mhz-845Mhz, 845Mhz-847Mhz, 830Mhz-832Mhz, 843Mhz-845Mhz, 845Mhz-847Mhz and 845Mhz-847 Mhz.

It can be seen that the resonant frequencies of the first filtering branch 14, the second filtering branch 15, the fifth filtering branch 24, and the sixth filtering branch 25 on the first surface 111 are substantially the same, so that the convenience of manufacturing and debugging the filter 10 is improved, that is, the same specification parameters can be adopted for manufacturing in the manufacturing process, and the required parameter range can be reached only by simple debugging in the actual process.

It can be seen that the resonant frequencies of the third filtering branch 16, the fourth filtering branch 17, the seventh filtering branch 26, and the eighth filtering branch 27 on the second surface 112 are substantially the same, so that the convenience of manufacturing and debugging the filter 10 is improved, that is, the same specification parameters can be adopted for manufacturing in the manufacturing process, and the required parameter range can be reached only by simple debugging in the actual process.

As shown in fig. 11, fig. 11 is a schematic diagram of simulation results of the filter provided in the present application. Through experimental tests, the bandwidths of the third filtering branch 16 and the seventh filtering branch 26 of the present application are in the range of 789Mhz-824Mhz, as shown by the frequency band curve 31 in fig. 11; the bandwidths of the fourth filtering branch 17 and the eighth filtering branch 27 of the present application are in the range of 826Mhz-865Mhz, as shown by the frequency band curve 32 in fig. 11; the bandwidth of the second filtering branch 15 and the sixth filtering branch 25 of the present application is in the range of 878Mhz-979Mhz, as shown by the frequency band curve 33 in fig. 11; the bandwidth of the first 14 and fifth 24 filtering branches of the present application lies in the range 919Mhz-962Mhz, as shown by the band curve 34 in fig. 11.

The bandwidth of the frequency band curve 31 is greater than or equal to 28dB at 787Mhz, greater than 22dB at 788Mhz, greater than 17dB at 789Mhz, greater than 10dB at 789.5Mhz, greater than 3.5dB at 790Mhz, and greater than 105dB at 832 Mhz.

Wherein, the bandwidth rejection of the band curve 32 is greater than 75dB at a frequency of 821Mhz and greater than 40dB at a frequency of 880 Mhz.

The bandwidth rejection of the frequency band curve 33 is greater than 40dB at a frequency of 862Mhz, greater than 20dB at a frequency of 870Mhz, greater than 3dB at a frequency of 875Mhz, and greater than 80dB at a frequency of 925 Mhz.

Wherein, the bandwidth of the band curve 34 is suppressed more than 105dB at 915Mhz, and is suppressed more than 27dB at 970 Mhz.

Therefore, the performance of the filter 10 such as out-of-band rejection can be improved.

Further, as shown in the frequency band curve 31 in fig. 11, one cross-coupling zero 161 of the third filtering branch 16 is zero a, and the frequency of the zero a is 790Mhz, where the bandwidth rejection is greater than 25 dB. As shown in the frequency band curve 32 in fig. 11, one cross-coupling zero 171 of the fourth filtering branch 17 is zero B, and the frequency of zero B is 822Mhz, and the bandwidth rejection is greater than 88 dB. As shown in the frequency band curve 33 of fig. 11, one cross-coupling zero 121 of the second filtering branch 15 is zero C, and the frequency of zero C is 868Mhz, where the bandwidth rejection is greater than 55 dB. As shown in the frequency band curve 34 of fig. 11, one cross-coupling zero 141 of the first filtering branch 14 is zero D, and the frequency of zero D is 915Mhz, and the bandwidth rejection is greater than 120 dB.

It should be noted that the parameters (e.g., frequency point and suppression) of two or more coupling zeros of the present application may be the same; in the simulation diagram, the coupling zeros of the same parameters are shown as the same coupling zeros.

Therefore, the filter 10 of the present application can reduce the size of the filter 10 and improve the performance of the filter 10 such as out-of-band rejection.

The present application further provides a communication system, as shown in fig. 12, fig. 12 is a schematic structural diagram of an embodiment of the communication system of the present application. The communication system 40 of the present embodiment includes an antenna 41 and a radio frequency unit 42 connected to the antenna 41, the radio frequency unit 42 includes the filter 10 as shown in the above-mentioned embodiment, and the filter 10 is used for filtering the radio frequency signal. In other embodiments, the rf Unit 42 may be integrally designed with the Antenna 41 to form an Active Antenna Unit (AAU).

Some embodiments of the present application are referred to as filters, and it is understood that in other embodiments, the present application may also be a combiner, i.e., a dual-frequency combiner.

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:

2. The filter of claim 1,

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

the first filtering cavity, the fifth filtering cavity, the sixth filtering cavity and the ninth filtering cavity of the first filtering branch are in a row and are sequentially arranged along the first direction;

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

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

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

a first filtering cavity of the first filtering branch is respectively adjacent to a second filtering cavity, a third filtering cavity, a fifth filtering cavity and the first common cavity;

the sixth filtering cavity of the first filtering branch is respectively adjacent to the fourth filtering cavity, the fifth filtering cavity, the seventh filtering cavity, the ninth filtering cavity, the sixth filtering cavity and the eighth filtering cavity of the second filtering branch;

a ninth filtering cavity of the first filtering branch is respectively adjacent to a sixth filtering cavity, a seventh filtering cavity, an eighth filtering cavity and a tenth filtering cavity;

the eighth filtering cavity of the first filtering branch is respectively intersected with the seventh filtering cavity and the ninth filtering cavity;

and a fourth filtering cavity of the second filtering branch is respectively adjacent to the first filtering cavity, the third filtering cavity, the fifth filtering cavity, the sixth filtering cavity and the seventh filtering cavity.

3. The filter of claim 2,

capacitive cross coupling is respectively carried out between a first filtering cavity and a third filtering cavity, between a fourth filtering cavity and a sixth filtering cavity and between a seventh filtering cavity and a ninth filtering cavity of the first filtering branch, and inductive cross coupling is carried out between the fourth filtering cavity and the seventh filtering cavity so as to form four cross coupling zeros of the first filtering branch;

and inductive cross coupling is respectively performed between the first filtering cavity and the third filtering cavity, between the fourth filtering cavity and the sixth filtering cavity, and between the fourth filtering cavity and the seventh filtering cavity of the second filtering branch so as to form three cross coupling zeros of the second filtering branch.

4. The filter of claim 3,

a fourth filtering cavity to an eighth filtering cavity of the third filtering branch are arranged in a W shape;

the projection of the center of the first filtering cavity and the projection of the center of the third filtering cavity in the first direction are positioned between the center of the second filtering cavity and the projection of the center of the fourth filtering cavity in the second direction are positioned between the center of the first filtering cavity and the projection of the center of the third filtering cavity in the second direction;

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

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

the projection of the center of the third filtering cavity and the projection of the center of the fourth filtering cavity in the first direction are positioned between the center of the second filtering cavity and the projection of the center of the fifth filtering cavity in the first direction, and the projection of the center of the second filtering cavity and the projection of the center of the fourth filtering cavity in the second direction are positioned between the center of the first filtering cavity and the projection of the center of the third filtering cavity in the second direction;

the fifth filtering cavity to the seventh filtering cavity of the fourth filtering branch are arranged in a triangular shape, the projection of the center of the sixth filtering cavity in the first direction is positioned between the center of the fifth filtering cavity and the projection of the center of the seventh filtering cavity in the first direction, and the projection of the center of the seventh filtering cavity in the second direction is positioned between the center of the fifth filtering cavity and the projection of the center of the sixth filtering cavity in the second direction;

the first filtering cavity of the third filtering branch is respectively adjacent to the second filtering cavity, the third filtering cavity, the fourth filtering cavity, the fifth filtering cavity and the second common cavity;

a seventh filtering cavity of the third filtering branch is respectively adjacent to a fifth filtering cavity, a sixth filtering cavity, an eighth filtering cavity, a tenth filtering cavity, a fourth filtering cavity of the fourth filtering branch and the sixth filtering cavity;

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

and the second filter cavity of the fourth filter branch is respectively adjacent to the first filter cavity, the third filter cavity, the fourth filter cavity, the fifth filter cavity of the third filter branch and the second common cavity.

5. The filter of claim 4,

capacitive cross coupling is respectively performed between a fourth filtering cavity and a sixth filtering cavity of the third filtering branch, between an eighth filtering cavity and a tenth filtering cavity of the third filtering branch, and inductive cross coupling is performed between the sixth filtering cavity and the eighth filtering cavity of the third filtering branch so as to form three cross coupling zeros of the third filtering branch;

capacitive cross coupling is respectively performed between the first filtering cavity and the third filtering cavity of the fourth filtering branch circuit and between the fourth filtering cavity and the sixth filtering cavity of the fourth filtering branch circuit, so that two cross coupling zeros of the fourth filtering branch circuit are formed.

6. The filter of claim 5, further comprising:

a third common cavity disposed on the first surface, and a fourth common cavity disposed on the second surface;

the fifth filtering branch is arranged on the first surface, is coupled with the third common cavity, and consists of ten filtering cavities which are sequentially coupled, wherein the ten filtering cavities of the fifth filtering branch further form four cross-coupling zeros;

the sixth filtering branch is arranged on the first surface, is coupled with the third common cavity, and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the sixth filtering cavity branch further form three cross-coupling zero points;

the first filtering cavity of the fifth filtering branch is intersected with the third common cavity;

the seventh filtering branch is arranged on the second surface, is coupled with the fourth common cavity, and consists of eleven filtering cavities which are sequentially coupled, and the eleven filtering cavities of the seventh filtering branch further form three cross-coupling zeros;

the eighth filtering branch is arranged on the second surface, is coupled with the fourth common cavity, and consists of eight filtering cavities which are sequentially coupled, and the eight filtering cavities of the eighth filtering cavity branch further form two cross-coupling zero points;

and the first filtering cavity of the seventh filtering branch circuit is intersected with the fourth common cavity.

7. The filter of claim 6,

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

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

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

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

the first filtering cavity to the fourth filtering cavity of the sixth filtering branch are arranged in a quadrilateral mode, the projection of the center of the first filtering cavity and the center of the second filtering cavity in the first direction is located between the projection of the center of the third filtering cavity and the projection of the center of the fourth filtering cavity in the first direction, and the projection of the center of the second filtering cavity and the projection of the center of the fourth filtering cavity in the second direction is located between the projection of the center of the third filtering cavity and the projection of the center of the first filtering cavity in the second direction;

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

the sixth filtering cavity to the eighth filtering cavity of the sixth filtering branch are arranged in a triangular shape, the projection of the center of the sixth filtering cavity in the first direction is located between the projection of the center of the seventh filtering cavity and the projection of the center of the eighth filtering cavity in the first direction, and the projection of the center of the eighth filtering cavity in the second direction is located between the projection of the center of the seventh filtering cavity and the projection of the center of the sixth filtering cavity in the second direction;

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

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

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

the first filtering cavity of the fifth filtering branch is respectively adjacent to the second filtering cavity, the third filtering cavity, the fourth filtering cavity and the third common cavity;

a ninth filtering cavity of the fifth filtering branch is respectively adjacent to the third filtering cavity, the eighth filtering cavity and the tenth filtering cavity;

and a fifth filtering cavity of the fifth filtering branch is respectively adjacent to a fourth filtering cavity, a sixth filtering cavity, a seventh filtering cavity, an eighth filtering cavity and an eighth filtering cavity of the sixth filtering branch.

8. The filter of claim 7,

capacitive cross coupling is respectively performed between a first filtering cavity and a third filtering cavity, between a fifth filtering cavity and a seventh filtering cavity, and between an eighth filtering cavity and a tenth filtering cavity of the fifth filtering branch, and the seventh filtering cavity and the tenth filtering cavity are inductively cross coupled to form four cross coupling zeros of the fifth filtering branch;

and the first filtering cavity and the fourth filtering cavity of the sixth filtering branch, the second filtering cavity and the fourth filtering cavity, and the sixth filtering cavity and the eighth filtering cavity of the sixth filtering branch are respectively subjected to inductive cross coupling so as to form three cross coupling zeros of the sixth filtering branch.

9. The filter of claim 8,

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

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

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

the eighth filtering cavity to the tenth filtering cavity of the seventh filtering branch are arranged in a triangular shape, the projection of the center of the ninth filtering cavity in the first direction is located between the projection of the center of the eighth filtering cavity and the projection of the center of the tenth filtering cavity in the first direction, and the projection of the center of the eighth filtering cavity in the second direction is located between the projection of the center of the ninth filtering cavity and the projection of the center of the tenth filtering cavity in the second direction;

an eleventh filter cavity and a tenth filter cavity of the seventh filter branch are arranged in an intersecting manner;

the first filtering cavity and the fourth filtering cavity of the eighth filtering branch are arranged in a rhombic shape, the projection of the center of the first filtering cavity and the center of the fourth filtering cavity in the first direction is positioned between the projection of the center of the second filtering cavity and the projection of the center of the third filtering cavity in the first direction, and the projection of the center of the second filtering cavity and the projection of the center of the third filtering cavity in the second direction is positioned between the projection of the center of the first filtering cavity and the projection of the center of the fourth filtering cavity in the second direction;

the fourth filtering cavity to the eighth filtering cavity of the eighth filtering branch are sequentially arranged along the first direction;

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

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

the eighth filtering cavity of the eighth filtering branch is respectively adjacent to the seventh filtering cavity, the eighth filtering cavity of the seventh filtering branch, the ninth filtering cavity of the seventh filtering branch and the fifth filtering cavity of the fourth filtering branch;

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

an eleventh filter cavity of the seventh filter branch is respectively adjacent to the tenth filter cavity and the fifth filter cavity;

the eighth filtering cavity of the seventh filtering branch is respectively adjacent to the sixth filtering cavity, the seventh filtering cavity, the ninth filtering cavity, the tenth filtering cavity and the eighth filtering cavity of the eighth filtering branch;

inductive cross coupling is respectively performed between a fourth filtering cavity and a sixth filtering cavity of the seventh filtering branch and between an eighth filtering cavity and a tenth filtering cavity of the seventh filtering branch, and capacitive cross coupling is performed between the sixth filtering cavity and the eighth filtering cavity to form three cross coupling zeros of the seventh filtering branch;

and the second filtering cavity and the fourth filtering cavity of the eighth filtering branch are capacitively and cross-coupled, and the second filtering cavity and the fifth filtering cavity are inductively and cross-coupled, so that two cross-coupling zeros of the eighth filtering branch are formed.

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