CN113054365A

CN113054365A - Communication system and filter thereof

Info

Publication number: CN113054365A
Application number: CN201911383485.6A
Authority: CN
Inventors: 杨绍春; 张海峰; 贺从虎; 李炳才
Original assignee: Shenzhen Tatfook Technology Co Ltd
Current assignee: Shenzhen Tatfook Technology Co Ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2021-06-29

Abstract

The application discloses a communication system and a filter thereof. The filter includes: the third filtering branch, the first filtering branch, the second filtering branch and the fourth filtering branch are sequentially arranged on the shell along the second direction; nine filter cavities of the first filter branch further form three inductive cross coupling zero points, and the second filter branch and the first filter branch are symmetrically arranged; ten filter cavities of the third filter branch further form four inductive cross coupling zeros; ten filter cavities of the fourth filter branch further form four inductive cross coupling zeros; the first filtering cavity to the sixth filtering cavity of the third filtering branch and the first filtering cavity to the sixth filtering cavity of the fourth filtering branch are symmetrically arranged; in this way, the filter cavity symmetry setting of this application can reduce the wave filter volume, and the debugging and reduction in production cost of being convenient for, and the setting at pure cross coupling zero point can realize the suppression at zero point, and the debugging index of being convenient for, the material uniformity is good, reduces the product complexity.

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 the filter cavity arrangement in the existing filter is irregular in long-term research and development work, so that the filter is large in size, inconvenient to debug and high in production cost; in order to improve the zero suppression effect of the filter, the filter is usually provided with two or more cross-coupling zeros, which results in multiple material types, high production cost and poor product stability.

Disclosure of Invention

The application provides a filter to solve prior art's filter chamber and arrange irregularly, lead to the wave filter bulky, be not convenient for the debugging, manufacturing cost is high, and the material kind is many, the poor technical problem of product stability.

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 third filtering branch, the first filtering branch, the second filtering branch and the fourth filtering branch are sequentially arranged on the shell along the second direction;

the first filtering branch consists of nine filtering cavities which are coupled in sequence, the nine filtering cavities of the first filtering branch further form three inductive cross coupling zero points, and the second filtering branch is symmetrically arranged with the first filtering branch;

the third filtering branch consists of ten filtering cavities which are coupled in sequence, and the ten filtering cavities of the third filtering branch further form four inductive cross-coupling zeros;

the fourth filtering branch consists of ten filtering cavities which are coupled in sequence, and the ten filtering cavities of the fourth filtering branch further form four inductive cross-coupling zeros;

and the first filtering cavity to the sixth filtering cavity of the third filtering branch and the first filtering cavity to the sixth filtering cavity of the fourth filtering branch are symmetrically arranged.

In order to solve the above problem, an embodiment of the present application provides a communication system, where the communication system includes an antenna and a radio frequency unit connected to the antenna, and the radio frequency unit includes the filter as described above and is configured to filter a radio frequency signal.

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 third filtering branch, the first filtering branch, the second filtering branch and the fourth filtering branch are sequentially arranged on the shell along the second direction; the first filtering branch consists of nine filtering cavities which are coupled in sequence, the nine filtering cavities of the first filtering branch further form three inductive cross coupling zero points, and the second filtering branch is symmetrically arranged with the first filtering branch; the third filtering branch consists of ten filtering cavities which are coupled in sequence, and the ten filtering cavities of the third filtering branch further form four inductive cross coupling zeros; the fourth filtering branch consists of ten filtering cavities which are sequentially coupled, and the ten filtering cavities of the fourth filtering branch further form four inductive cross coupling zeros; the first filtering cavity to the sixth filtering cavity of the third filtering branch and the first filtering cavity to the sixth filtering cavity of the fourth filtering branch are symmetrically arranged; in this way, the filter cavity symmetry setting of this application can reduce the filter volume, and the debugging and reduction in production cost of being convenient for, the setting at pure cross coupling zero point can realize the suppression at zero point, and the debugging index of being convenient for reaches the design requirement, and the material kind reduces, can reduce the product complexity, and the material uniformity is good, and product stability is high.

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 third filtering branch provided in the present application;

FIG. 4 is a schematic diagram of another embodiment of a filter provided herein;

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

FIG. 6 is a diagram illustrating a first simulation result of the filter provided herein;

FIG. 7 is a diagram illustrating a second simulation result of the filter provided herein;

FIG. 8 is a diagram illustrating a third simulation result of the filter provided herein;

fig. 9 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, a first filtering branch 12, a second filtering branch 13, a third filtering branch 14, and a fourth filtering branch 15; the first filtering branch 12, the second filtering branch 13, the third filtering branch 14 and the fourth filtering branch 15 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 12, the second filtering branch 13, the third filtering branch 14, and the fourth filtering branch 15 are all receiving filtering branches. The housing 11 has a first direction L and a second direction D, and the first direction L of the housing 11 is perpendicular to the second direction D of the housing 11.

The third filtering branch 14, the first filtering branch 12, the second filtering branch 13 and the fourth filtering branch 15 are sequentially disposed on the housing 11 along the second direction D.

The first filtering branch 12 is composed of nine filtering cavities coupled in sequence, and the nine filtering cavities of the first filtering branch 12 further form three inductive cross-coupling zeros 121.

And the second filtering branch 13 is composed of nine filtering cavities coupled in sequence, the nine filtering cavities of the second filtering branch 13 further form three inductive cross-coupling zeros 131, and the second filtering branch 13 and the first filtering branch 12 are symmetrically arranged.

And the third filtering branch 14 is composed of ten filtering cavities which are coupled in sequence, and the ten filtering cavities of the third filtering branch 14 further form four inductive cross-coupling zeros 141.

The fourth filtering branch 15 is composed of ten filtering cavities coupled in sequence, and the ten filtering cavities of the fourth filtering branch 15 further form four inductive cross-coupling zeros 151.

The first filter cavity C1 through the sixth filter cavity C6 of the third filter branch 14 and the first filter cavity D1 through the sixth filter cavity D6 of the fourth filter branch 15 are symmetrically disposed.

The partial filtering cavity symmetry setting of this application can reduce the wave filter volume, and the debugging and reduction in production cost of being convenient for, the setting at pure cross coupling zero point can realize the suppression at zero point, and the debugging index of being convenient for reaches the design requirement, and the material kind reduces, can reduce the product complexity, and the material uniformity is good, and product stability is high.

The first filtering cavity a1, the second filtering cavity a2, the sixth filtering cavity a6, the eighth filtering cavity A8 and the ninth filtering cavity a9 of the first filtering branch 12 are in a row and are sequentially arranged along the first direction L; the third filtering cavity A3, the fifth filtering cavity a5, the seventh filtering cavity a7 of the first filtering branch 12, the fourth filtering cavity C4 and the sixth filtering cavity C6 of the third filtering branch 14 are in a row and are sequentially arranged along the first direction L; the fourth filtering cavity a4 of the first filtering branch 12, the second filtering cavity C2 of the third filtering branch 14, the third filtering cavity C3 and the fifth filtering cavity C5 are in a row and are sequentially arranged along the first direction L; the ninth filtering cavity C9 and the tenth filtering cavity C10 of the third filtering branch 14 are in a row and are sequentially arranged along the second direction D; the sixth filtering cavity C6 to the ninth filtering cavity C9 of the third filtering branch 14 are quadrilateral, the projection of the center of the seventh filtering cavity C7 and the center of the eighth filtering cavity C8 in the first direction L is located between the projections of the centers of the ninth filtering cavity C9 in the center of the sixth filtering cavity C6 in the first direction L, and the projection of the centers of the sixth filtering cavity C6 and the ninth filtering cavity C9 in the second direction D is located between the centers of the seventh filtering cavity C7 and the projection of the centers of the eighth filtering cavity C8 in the second direction D.

Further, the eighth filtering cavity C8 of the third filtering branch 14 is respectively disposed adjacent to the sixth filtering cavity C6, the ninth filtering cavity C9 and the tenth filtering cavity C10; the fourth filtering cavity C4 of the third filtering branch 14 is respectively adjacent to the third filtering cavity C3, the fifth filtering cavity C5, the sixth filtering cavity C6, the seventh filtering cavity a7, the eighth filtering cavity A8 and the ninth filtering cavity a9 of the first filtering branch 12; the third filtering cavity C3, the fifth filtering cavity C5, the sixth filtering cavity C6 of the third filtering branch 14, the seventh filtering cavity a7, the eighth filtering cavity a8 and the ninth filtering cavity a9 of the first filtering branch 12 are arranged in a regular hexagon; the first filter cavity C1 of the third filter branch 14 is respectively arranged adjacent to the second filter cavity C2 and the third filter cavity C3; the fifth filtering cavity a5 of the first filtering branch 12 is respectively adjacent to the second filtering cavity a2, the third filtering cavity A3, the fourth filtering cavity a4, the sixth filtering cavity a6, the seventh filtering cavity a7 and the second filtering cavity C2 of the third filtering branch 14; the second filtering cavity a2, the third filtering cavity A3, the fourth filtering cavity a4, the sixth filtering cavity a6, the seventh filtering cavity a7 of the first filtering branch 12 and the second filtering cavity C2 of the third filtering branch 14 are arranged in a regular hexagon; the first filter cavity a1 of the first filter branch 12 is arranged adjacent to the second filter cavity a2 and the third filter cavity A3, respectively.

Nine filter cavities of the first filter branch 12 and ten filter cavities of the third filter branch 14 are regularly arranged, so that the space in the shell 11 can be saved, the size of the filter 10 can be reduced, and the stability of the filter 10 can be improved. Further, nine filter cavities of the first filter branch 12 and ten filter cavities of the third filter branch 14 are the same in size, so that the first filter cavity a1 to the ninth filter cavity a9 of the first filter branch 12 and the first filter cavity C1 to the tenth filter cavity C10 of the third filter branch 14 in the housing 11 can be equidistantly distributed, the distances between the centers of any two adjacent filter cavities are equal, the arrangement is compact, the layout and debugging are facilitated, and the consistency of the filter 10 is improved.

The cavity array of the first filtering cavity B1 through the ninth filtering cavity B9 of the second filtering branch 13 is consistent with the cavity array of the first filtering cavity a1 through the ninth filtering cavity a9 of the first filtering branch 12, and will not be described herein again.

The fifth filtering cavity D5 to the seventh filtering cavity D7 of the fourth filtering branch 15 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; the ninth filtering cavity D9 and the eighth filtering cavity D8 of the fourth filtering branch 15 are in a row and are sequentially arranged along the second direction D; the seventh filtering cavity D7 of the fourth filtering branch 15 is respectively adjacent to the sixth filtering cavity D6, the eighth filtering cavity D8 and the ninth filtering cavity D9, and the seventh filtering cavity D7 and the sixth filtering cavity D6 of the fourth filtering branch 15 are intersected.

Optionally, referring to fig. 1, the seventh filtering cavity D7 of the fourth filtering branch 15 intersects the cavity circle of the sixth filtering cavity D6 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 seventh filtering cavity D7 and the sixth filtering cavity D6 form a window coupling, and the width of the window is equal to the length of the 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.

Further, as shown in fig. 2, the first filter cavity a1 and the third filter cavity A3, the third filter cavity A3 and the fifth filter cavity a5, and the sixth filter cavity a6 and the eighth filter cavity A8 of the first filter branch 12 are inductively cross-coupled to form three inductive cross-coupling zeros 121 of the first filter branch 12, such as inductances L1, L2, and L3 shown in fig. 2, respectively. The arrangement of the inductive cross-coupling zero point 121 of the first filtering branch 12 can realize zero point suppression, so that the debugging indexes are convenient, and the design requirements are met, and moreover, the purely inductive cross-coupling zero point 121 can reduce the product complexity, so that the material consistency of the filter 10 is good, and the product stability is high.

Specifically, a window may be disposed between the first filter cavity a1 and the third filter cavity A3 of the first filter branch 12, and a metal coupling rib is disposed on the window, so that the inductive cross-coupling is achieved between the first filter cavity a1 and the third filter cavity A3, and an inductive cross-coupling zero 121 is formed, which is equivalent to the inductance L1 in fig. 2. A window may be disposed between the third filter cavity A3 and the fifth filter cavity a5 of the first filter branch 12, and a metal coupling rib is disposed on the window, so that the third filter cavity A3 and the fifth filter cavity a5 realize inductive cross coupling, and an inductive cross coupling zero 121 is formed, which is equivalent to the inductance L2 in fig. 2. A window may be disposed between the sixth filtering cavity a6 and the eighth filtering cavity A8 of the first filtering branch 12, and a metal coupling rib is disposed on the window, so that the sixth filtering cavity a6 and the eighth filtering cavity A8 realize inductive cross coupling, and an inductive cross coupling zero 121 is formed, which is equivalent to the inductance L3 in fig. 2. In this embodiment, the inductive cross coupling is realized by the metal coupling rib, and the metal coupling rib is less subject to the change of the external temperature, so as to prevent the filter 10 from generating the temperature drift.

The cross-coupling zero setting mode of the second filtering branch 13 is consistent with the cross-coupling zero setting mode of the first filtering branch 12, and is not described herein again.

As shown in fig. 3, the four inductive cross-coupling zeros 141 of the third filtering branch 14 are respectively formed by inductive cross-coupling between the first filtering cavity C1 and the third filtering cavity C3, between the third filtering cavity C3 and the fifth filtering cavity C5, between the fifth filtering cavity C5 and the seventh filtering cavity C7, and between the seventh filtering cavity C7 and the ninth filtering cavity C9 of the third filtering branch 14, such as the inductors L1, L2, L3, and L4 shown in fig. 3. The inductive cross-coupling zero point 141 of the third filtering branch 14 is configured to achieve zero point suppression, so that the debugging indexes are facilitated, and the design requirements are met.

Specifically, a window may be disposed between the first filter cavity C1 and the third filter cavity C3 of the third filter branch 14, and a metal coupling rib is disposed on the window, so that the inductive cross-coupling is achieved between the first filter cavity C1 and the third filter cavity C3, and an inductive cross-coupling zero 141 is formed, which is equivalent to the inductance L1 in fig. 3. A window may be disposed between the third filter cavity C3 and the fifth filter cavity C5 of the third filter branch 14, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is achieved between the third filter cavity C3 and the fifth filter cavity C5, and an inductive cross coupling zero 141 is formed, which is equivalent to the inductance L2 in fig. 3. A window may be disposed between the fifth filter cavity C5 and the seventh filter cavity C7 of the third filter branch 14, and a metal coupling rib is disposed on the window, so that the inductive cross coupling is achieved between the fifth filter cavity C5 and the seventh filter cavity C7, and an inductive cross coupling zero 141 is formed, which is equivalent to the inductor L3 in fig. 3. A window may be disposed between the seventh filtering cavity C7 and the ninth filtering cavity C9 of the third filtering branch 14, and a metal coupling rib is disposed on the window, so that the inductive cross-coupling is achieved between the seventh filtering cavity C7 and the ninth filtering cavity C9, and an inductive cross-coupling zero 141 is formed, which is equivalent to the inductor L4 in fig. 3. 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 cross-coupling zero setting mode of the fourth filtering branch 15 is the same as the cross-coupling zero setting mode of the third filtering branch 14, and is not described herein again.

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 embodiment, part of the filter cavities are symmetrically arranged, so that the size of the filter can be reduced, debugging and production cost reduction are facilitated, zero point inhibition can be realized by the arrangement of the pure cross coupling zero point, the debugging index is facilitated, the design requirement is met, the material types are reduced, the product complexity can be reduced, the material consistency is good, and the product stability is high; nine filter cavities of the first filter branch 12 and ten filter cavities of the third filter branch 14 are regularly arranged, so that the space in the shell 11 can be saved, the size of the filter 10 can be reduced, and the stability of the filter 10 can be improved. Further, the nine filter cavities of the first filter branch 12 and the ten filter cavities of the third filter branch 14 are the same in size, so that the first filter cavity a1 to the ninth filter cavity a9 of the first filter branch 12 and the first filter cavity C1 to the tenth filter cavity C10 of the third 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; the zero point suppression can be realized by the arrangement of the inductive cross coupling zero point 121 of the first filtering branch 12, the inductive cross coupling zero point 131 of the second filtering branch 13, the inductive cross coupling zero point 141 of the third filtering branch 14 and the inductive cross coupling zero point 151 of the fourth filtering branch 15, so that the debugging index is convenient, the design requirement is met, the product complexity can be reduced by the pure inductive cross coupling zero point, the material consistency of the filter 10 is good, and the product stability is high.

Referring to fig. 4, fig. 4 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 fifth filtering branch 16 and a sixth filtering branch 17 on the basis of the embodiment shown in fig. 1.

The fifth filtering branch 16, the third filtering branch 14, the first filtering branch 12, the second filtering branch 13, the fourth filtering branch 15 and the sixth filtering branch 17 are sequentially arranged on the housing 11 along the second direction D.

And the fifth filtering branch 16 is arranged on the housing 11 and is composed of eleven sequentially coupled filtering cavities, and the eleven filtering cavities of the fifth filtering branch 16 further form four cross-coupling zeros 161.

And the sixth filtering branch 17 is arranged on the housing 11 and is composed of eleven filtering cavities coupled in sequence, and the eleven filtering cavities of the sixth filtering branch 17 further form four cross-coupling zeros 171.

In the present embodiment, the fifth filtering branch 16 and the sixth filtering branch 17 are transmitting filtering branches.

The third filter cavity E3 and the fifth filter cavity E5 of the fifth filter branch 16 are in a row and are sequentially arranged along the first direction L; the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch 16 are in a row and are sequentially arranged along the first direction L; the ninth filtering cavity E9 and the eighth filtering cavity E8 of the fifth filtering branch 16 are in a row and are sequentially arranged along the first direction L; the fourth filter cavity E4 to the sixth filter cavity E6 and the ninth filter cavity E9 of the fifth filter branch 16 are quadrilateral, the projection of the center of the fifth filter cavity E5 and the center of the ninth filter cavity E9 in the first direction L is positioned between the center of the sixth filter cavity E6 and the projection of the center of the fourth filter cavity E4 in the first direction L, and the projection of the center of the sixth filter cavity E6 and the projection of the center of the fourth filter cavity E4 in the second direction D is positioned between the center of the fifth filter cavity E5 and the projection of the center of the ninth filter cavity E9 in the second direction D; the ninth filter cavity E9 to the eleventh filter cavity E11 of the fifth filter branch 16 are arranged in a triangle, a projection of the center of the ninth filter cavity E9 in the first direction L is located between a center of the tenth filter cavity E10 and a projection of the center of the eleventh filter cavity E11 in the first direction L, and a projection of the center of the tenth filter cavity E10 in the second direction D is located between a center of the ninth filter cavity E9 and a center of the eleventh filter cavity E11.

Further, the first filter cavity E1 of the fifth filter branch 16 is respectively disposed adjacent to the second filter cavity E2, the first filter cavity C1 of the third filter branch 14 and the fifth filter cavity C5; the fourth filter cavity E4 of the fifth filter branch 16 is respectively adjacent to the third filter cavity E3, the fifth filter cavity E5, the ninth filter cavity E9, the tenth filter cavity E10 and the ninth filter cavity C9 of the third filter branch 14; the tenth filter cavity E10 of the fifth filter branch 16 is arranged to intersect the eleventh filter cavity E11.

As shown in fig. 5, the sixth filter cavity E6 and the eighth filter cavity E8 of the fifth filter branch 16 are inductively cross-coupled, and the third filter cavity E3 and the fifth filter cavity E5, the sixth filter cavity E6 and the ninth filter cavity E9, and the ninth filter cavity E9 and the eleventh filter cavity E11 are capacitively cross-coupled, respectively, to form four cross-coupling zeros 161 of the fifth filter branch 16, such as the inductor L1, the capacitors C1, C2, and C3 shown in fig. 5. The zero point suppression can be realized by the arrangement of the cross-coupling zero point 161 of the fifth filtering branch 16, so that the debugging index is facilitated, and the design requirement is met.

Specifically, a window may be disposed between the sixth filtering cavity E6 and the eighth filtering cavity E8 of the fifth filtering branch 16, and a metal coupling rib is disposed on the window, so that the inductive cross-coupling is achieved between the first filtering cavity G1 and the fourth filtering cavity G4, and an inductive cross-coupling zero point is formed, which is equivalent to the inductance L1 in fig. 5. A window may be disposed between the third filter cavity E3 and the fifth filter cavity E5 of the fifth filter branch 16, and a capacitive fly rod may be disposed at the window, so that capacitive cross coupling is achieved between the third filter cavity E3 and the fifth filter cavity E5, and a capacitive cross coupling zero point is formed, which is equivalent to the inductor C1 in fig. 5. A window may be disposed between the sixth filter cavity E6 and the ninth filter cavity E9 of the fifth filter branch 16, and a capacitive fly rod may be disposed at the window, so that capacitive cross coupling is achieved between the sixth filter cavity E6 and the ninth filter cavity E9, and a capacitive cross coupling zero point is formed, which is equivalent to the inductor C2 in fig. 5. A window may be disposed between the ninth filter cavity E9 and the eleventh filter cavity E11 of the fifth filter branch 16, and a capacitive fly rod may be disposed at the window, so that capacitive cross coupling is achieved between the ninth filter cavity E9 and the eleventh filter cavity E11, and a capacitive cross coupling zero point is formed, which is equivalent to the inductor C3 in fig. 5. 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 filter cavity F3 to the fifth filter cavity F5 of the sixth filter branch 17 are arranged in a triangle, the projection of the center of the fourth filter cavity F4 in the first direction L is located between the center of the third filter cavity F3 and the projection of the center of the fifth filter cavity F5 in the first direction L, and the projection of the center of the third filter cavity F3 in the second direction D is located between the center of the fourth filter cavity F4 and the center of the fifth filter cavity F5;

the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 17 are in a row and are sequentially arranged along the first direction L; the sixth filtering cavity F6 to the ninth filtering cavity F9 of the sixth filtering branch 17 are quadrilateral, the projection of the center of the sixth filtering cavity F6 and the center of the eighth filtering cavity F8 in the first direction L is located between the projection of the center of the seventh filtering cavity F7 and the projection of the center of the ninth filtering cavity F9 in the first direction L, and the projection of the center of the sixth filtering cavity F6 and the projection of the center of the eighth filtering cavity F8 in the second direction D is located between the projection of the center of the seventh filtering cavity F7 and the projection of the center of the ninth filtering cavity F9 in the second direction D; the fourth filter cavity F4, the ninth filter cavity F9 to the eleventh filter cavity F11 of the sixth filter branch 17 are disposed in a quadrilateral shape, a projection of a center of the ninth filter cavity F9 and a center of the tenth filter cavity F10 in the first direction L is located between a center of the fourth filter cavity F4 and a projection of a center of the eleventh filter cavity F11 in the first direction L, and a projection of a center of the ninth filter cavity F9 and a projection of a center of the tenth filter cavity F10 in the second direction D is located between a center of the fourth filter cavity F4 and a projection of a center of the eleventh filter cavity F11 in the second direction D.

Further, the tenth filtering cavity F10 of the sixth filtering branch 17 is respectively disposed adjacent to the fourth filtering cavity F4, the eleventh filtering cavity F11 and the tenth filtering cavity D10 of the fourth filtering branch 15, and the tenth filtering cavity F10 and the eleventh filtering cavity F11 of the sixth filtering branch 17 are disposed in an intersecting manner; the fourth filter cavity F4 of the sixth filter branch 17 is respectively adjacent to the tenth filter cavity F10, the ninth filter cavity F9, the fifth filter cavity F5 and the eighth filter cavity D8 of the fourth filter branch 15; the second filter cavity F2 of the sixth filter branch 17 is respectively adjacent to the first filter cavity F1, the third filter cavity F3, and the seventh filter cavity D7 and the eighth filter cavity D8 of the fourth filter branch 15; the first filter cavity F1 of the sixth filter branch 17 is disposed adjacent to the second filter cavity F2, the first filter cavity D1 of the fourth filter branch 15 and the fifth filter cavity D5, respectively.

The cross-coupling zero setting mode of the sixth filtering branch 17 is the same as the cross-coupling zero setting mode of the fifth filtering branch 16, and is not described herein again.

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 filtering cavity a1 of the first filtering branch 12 is connected to the first port, and the ninth filtering cavity a9 of the first filtering branch 12 is connected to the second port; the first filtering cavity B1 of the second filtering branch 13 is connected with the third port, and the ninth filtering cavity a9 of the second filtering branch 13 is connected with the fourth port; the first filter cavity C1 of the third filter branch 14 is connected to the fifth port, and the tenth filter cavity C10 of the third filter branch 14 is connected to the sixth port; the first filter cavity D1 of the fourth filter branch 15 is connected to the seventh port, and the tenth filter cavity D10 of the fourth filter branch 15 is connected to the eighth port; the first filter cavity E1 of the fifth filter branch 16 is connected to the ninth port, and the eleventh filter cavity E11 of the fifth filter branch 16 is connected to the tenth port; the first filter cavity F1 of the sixth filter branch 17 is connected to the eleventh port, and the eleventh filter cavity F11 of the sixth filter branch 17 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 12 of this embodiment lies in the range 813Mhz-850 Mhz. In particular, the coupling bandwidth between the first port and the first filter cavity a1 of the first filter branch 12 ranges from 32Mhz to 40 Mhz; the coupling bandwidth between the first filter cavity a1 and the second filter cavity a2 of the first filter branch 12 ranges from 22Mhz to 29 Mhz; the coupling bandwidth between the first filter cavity a1 and the third filter cavity A3 of the first filter branch 12 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 12 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 12 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the third filter cavity A3 and the fifth filter cavity a5 of the first filter branch 12 ranges from 3Mhz to 8 Mhz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 12 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 12 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the sixth filter cavity a6 and the seventh filter cavity a7 of the first filter branch 12 ranges from 9Mhz to 15 Mhz; the coupling bandwidth between the sixth filter cavity a6 and the eighth filter cavity A8 of the first filter branch 12 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the seventh filter cavity a7 and the eighth filter cavity A8 of the first filter branch 12 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the eighth filter cavity A8 and the ninth filter cavity a9 of the first filter branch 12 ranges from 25Mhz to 33 Mhz; the coupling bandwidth between the ninth filter cavity a9 of the first filter branch 12 and the second port is in the range of 32Mhz-40 Mhz.

The bandwidth parameter of the second filtering branch 13 is the same as the bandwidth parameter of the first filtering branch 12, and is not described herein again.

The bandwidth of the third filtering branch 14 of this embodiment lies in the range 813Mhz-850 Mhz. In particular, the coupling bandwidth between the fifth port and the first filter cavity C1 of the third filter branch 14 ranges from 33Mhz to 41 Mhz; the coupling bandwidth between the first filter cavity C1 and the second filter cavity C2 of the third filter branch 14 ranges from 13Mhz to 19 Mhz; the coupling bandwidth between the first filter cavity C1 and the third filter cavity C3 of the third filter branch 14 ranges from 22Mhz to 29 Mhz; the coupling bandwidth between the second filter cavity C2 and the third filter cavity C3 of the third filter branch 14 ranges from 5Mhz to 10 Mhz; the coupling bandwidth between the third filter cavity C3 and the fourth filter cavity C4 of the third filter branch 14 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the third filter cavity C3 and the fifth filter cavity C5 of the third filter branch 14 ranges from 5Mhz to 10 Mhz; the coupling bandwidth between the fourth filter cavity C4 and the fifth filter cavity C5 of the third filter branch 14 ranges from 15Mhz to 21 Mhz; the coupling bandwidth between the fifth filter cavity C5 and the sixth filter cavity C6 of the third filter branch 14 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the fifth filter cavity C5 and the seventh filter cavity C7 of the third filter branch 14 ranges from 10Mhz to 16 Mhz; the coupling bandwidth between the sixth filter cavity C6 and the seventh filter cavity C7 of the third filter branch 14 ranges from 11Mhz to 17 Mhz; the coupling bandwidth between the seventh filter cavity C7 and the eighth filter cavity C8 of the third filter branch 14 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the seventh filter cavity C7 and the ninth filter cavity C9 of the third filter branch 14 ranges from 4Mhz to 9 Mhz; the coupling bandwidth between the eighth filter cavity C8 and the ninth filter cavity C9 of the third filter branch 14 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the ninth filter cavity C9 and the tenth filter cavity C10 of the third filter branch 14 ranges from 26Mhz to 34 Mhz; the coupling bandwidth between the tenth filtering cavity C10 and the fifth port of the third filtering branch 14 ranges from 33Mhz to 41 Mhz.

The bandwidth parameter of the fourth filtering branch 15 is the same as the bandwidth parameter of the third filtering branch 14, and is not described herein again.

The bandwidth of the fifth filtering branch 16 of the present embodiment is in the range of 858Mhz-895 Mhz. In particular, the coupling bandwidth between the ninth port and the first filter cavity E1 of the fifth filter branch 16 ranges from 32Mhz to 40 Mhz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 16 ranges from 25Mhz to 33 Mhz; the coupling bandwidth between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch 16 ranges from 17Mhz to 24 Mhz; the coupling bandwidth between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch 16 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the third filter cavity E3 and the fifth filter cavity E5 of the fifth filter branch 16 ranges from-10 Mhz to-5 Mhz; the coupling bandwidth between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 16 ranges from 14Mhz to 20 Mhz; the coupling bandwidth between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch 16 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch 16 ranges from 10Mhz to 16 Mhz; the coupling bandwidth between the sixth filter cavity E6 and the eighth filter cavity E8 of the fifth filter branch 16 ranges from-15 Mhz to-9 Mhz; the coupling bandwidth between the sixth filter cavity E6 and the ninth filter cavity E9 of the fifth filter branch 16 ranges from 0Mhz to 5 Mhz; the coupling bandwidth between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch 16 ranges from 8Mhz to 14 Mhz; the coupling bandwidth between the eighth filter cavity E8 and the ninth filter cavity E9 of the fifth filter branch 16 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the ninth filter cavity E9 and the tenth filter cavity E10 of the fifth filter branch 16 ranges from 10Mhz to 16 Mhz; the coupling bandwidth between the ninth filter cavity E9 and the eleventh filter cavity E11 of the fifth filter branch 16 ranges from 16Mhz to 23 Mhz; the coupling bandwidth between the tenth filter cavity E10 and the eleventh filter cavity E11 of the fifth filter branch 16 ranges from 18Mhz to 25 Mhz; the coupling bandwidth between the eleventh filter cavity E11 and the tenth port of the fifth filter branch 16 ranges from 32Mhz to 40 Mhz.

The bandwidth parameter of the sixth filtering branch 17 is the same as the bandwidth parameter of the fifth filtering branch 16, and is not described herein again.

Therefore, the resonant frequencies of the first filter cavity a1 through the ninth filter cavity a9 of the first filter branch 12 are sequentially located in the following ranges: 829Mhz-831Mhz, 839Mhz-841Mhz, 827Mhz-829Mhz, 835Mhz-837Mhz, 828Mhz-830Mhz, 843Mhz-845Mhz, 829Mhz-831 Mhz.

The resonant frequencies of the first filter cavity C1 through the tenth filter cavity C10 of the third filter branch 14 are sequentially in the following ranges: 829Mhz-831Mhz, 847Mhz-849Mhz, 827Mhz-829Mhz, 837Mhz-839Mhz, 827Mhz-829Mhz, 843Mhz-845Mhz, 828Mhz-830Mhz, 836Mhz-838Mhz, 829Mhz-831 Mhz.

The resonant frequencies of the first filter cavity E1 through the eleventh filter cavity E11 of the fifth filter branch 16 are sequentially in the following ranges: 874Mhz-876Mhz, 865Mhz-867Mhz, 874Mhz-876Mhz, 860Mhz-862Mhz, 871Mhz-873Mhz, 872Mhz-874Mhz, 889Mhz-891Mhz, 874Mhz-876 Mhz.

The frequency parameter of the second filtering branch 13 is the same as the frequency parameter of the first filtering branch 12, the frequency parameter of the fourth filtering branch 15 is the same as the frequency parameter of the third filtering branch 14, and the frequency parameter of the sixth filtering branch 17 is the same as the frequency parameter of the fifth filtering branch 16, which is not described herein again.

It can be seen that the resonant frequencies of the filter cavities of the first filtering branch 12 to the sixth filtering branch 17 are substantially the same, for example, the resonant frequencies of the filter cavities of the first filtering branch 12 and the second filtering branch 13 are completely the same, the resonant frequencies of the filter cavities of the third filtering branch 14 and the fourth filtering branch 15 are completely the same, and the resonant frequencies of the filter cavities of the fifth filtering branch 16 and the sixth filtering branch 17 are completely the same, so that the convenience of manufacturing and debugging the filter 10 is improved, that is, the filter can be manufactured by using the same specification parameters in the manufacturing process, and the required parameter range can be reached only by simple debugging in the actual process.

As shown in fig. 6, fig. 6 is a schematic diagram of a first simulation result of the filter provided in the present application. Through experimental tests, the bandwidths of the first filtering branch 12 and the second filtering branch 13 of the present application are in the range of 813Mhz-850Mhz, as shown by the frequency band curve 21 in fig. 6.

The bandwidth rejection of the band curve 21 is greater than 25dB in the frequency range 794Mhz-804Mhz, greater than 40dB in the frequency range 851Mhz-859Mhz, greater than 80dB in the frequency range 859Mhz-869Mhz, greater than 85dB in the frequency range 869Mhz-894Mhz, greater than 85dB in the frequency range 894Mhz-1020Mhz, greater than 90dB in the frequency range 1020Mhz-2690Mhz, and greater than 41dB in the frequency range 2690Mhz-3250 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 21 in fig. 6, one inductive cross-coupling zero 121 of the first filtering branch 12 is zero a, and the frequency of the zero a is 851Mhz, where the bandwidth rejection is greater than 46 dB.

As shown in fig. 7, fig. 7 is a schematic diagram of a second simulation result of the filter provided in the present application. Through experimental tests, the bandwidths of the third filtering branch 14 and the fourth filtering branch 15 of the present application are in the range of 813Mhz-850Mhz, as shown by the frequency band curve 22 in fig. 7.

The bandwidth rejection of the band curve 22 is greater than 25dB over the frequency range 794Mhz-804Mhz, greater than 40dB over the frequency range 851Mhz-859Mhz, greater than 80dB over the frequency range 859Mhz-869Mhz, greater than 85dB over the frequency range 869Mhz-894Mhz, greater than 85dB over the frequency range 894Mhz-1020Mhz, greater than 90dB over the frequency range 1020Mhz-2690Mhz, and greater than 41dB over the frequency range 2690Mhz-3250 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 22 in fig. 7, one inductive cross-coupling zero 141 of the third filtering branch 14 is zero B, and the frequency of the zero B is 852Mhz, where the bandwidth rejection is greater than 54 dB.

As shown in fig. 8, fig. 8 is a schematic diagram of a third simulation result of the filter provided in the present application. Through experimental tests, the bandwidths of the fifth filtering branch 16 and the sixth filtering branch 17 of the present application are in the range of 858Mhz-895Mhz, as shown by the frequency band curve 23 in fig. 8.

The band curve 23 has a bandwidth rejection of greater than 105dB in the frequency range of 0.9Mhz-849Mhz, a bandwidth rejection of greater than 38dB in the frequency range of 898.5Mhz-986.5Mhz, a bandwidth rejection of greater than 52dB in the frequency range of 1000Mhz-1710Mhz, a bandwidth rejection of greater than 104dB in the frequency range of 1710Mhz-1785Mhz, a bandwidth rejection of greater than 97dB in the frequency range of 1785Mhz-2570Mhz, a bandwidth rejection of greater than 105dB in the frequency range of 2570Mhz-2602Mhz, a bandwidth rejection of greater than 61dB in the frequency range of 2602Mhz-3550Mhz, a bandwidth rejection of greater than 61dB in the frequency range of 3550Mhz-3600Mhz, a bandwidth rejection of greater than 106dB in the frequency range of 3600Mhz-3800Mhz, a bandwidth rejection of greater than 38dB in the frequency range of 4345 Mhz-8470 Mhz, a bandwidth rejection of greater than 64 dB in the frequency range of 5332 Mhz-5214 Mhz, the bandwidth rejection is greater than 26dB, and is greater than 15dB in the frequency range of 5760Mhz-12750 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 23 in fig. 8, one cross-coupling zero 161 of the fifth filtering branch 16 is zero C, and the frequency of the zero C is 899Mhz, and the bandwidth rejection is greater than 68 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. 9, fig. 9 is a schematic structural diagram of an embodiment of the communication system of the present application. The communication system 30 of the present embodiment includes an antenna 31 and a radio frequency unit 32 connected to the antenna 31, the radio frequency unit 32 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 32 may be integrally designed with the Antenna 31 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:

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

2. The filter of claim 1,

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

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

the ninth filtering cavity and the tenth filtering cavity of the third filtering branch are in a row and are sequentially arranged along the second direction;

the projection of the center of the seventh filter cavity and the center of the eighth filter cavity in the first direction is positioned between the projections of the centers of the ninth filter cavity and the sixth filter cavity in the second direction, and the projection of the centers of the sixth filter cavity and the ninth filter cavity in the second direction is positioned between the projections of the centers of the seventh filter cavity and the eighth filter cavity in the second direction;

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

a fourth filter cavity of the third filter branch is respectively adjacent to a third filter cavity, a fifth filter cavity, a sixth filter cavity, a seventh filter cavity, an eighth filter cavity and a ninth filter cavity of the first filter branch; the third filtering cavity, the fifth filtering cavity, the sixth filtering cavity of the third filtering branch, the seventh filtering cavity, the eighth filtering cavity and the ninth filtering cavity of the first filtering branch are arranged in a regular hexagon;

the first filter cavity of the third filter branch is respectively adjacent to the second filter cavity and the third filter cavity;

the fifth filtering cavity of the first filtering branch is respectively adjacent to the second filtering cavity, the third filtering cavity, the fourth filtering cavity, the sixth filtering cavity, the seventh filtering cavity and the second filtering cavity of the third filtering branch; the second filtering cavity, the third filtering cavity, the fourth filtering cavity, the sixth filtering cavity, the seventh filtering cavity of the first filtering branch and the second filtering cavity of the third filtering branch are arranged in a regular hexagon;

and the first filter cavity of the first filter branch is respectively adjacent to the second filter cavity and the third filter cavity.

3. The filter of claim 2,

inductive cross coupling is respectively performed between the first filtering cavity and the third filtering cavity, between the third filtering cavity and the fifth filtering cavity, and between the sixth filtering cavity and the eighth filtering cavity of the first filtering branch, so as to form three inductive cross coupling zeros of the first filtering branch;

and the first filtering cavity and the third filtering cavity, the third filtering cavity and the fifth filtering cavity, the fifth filtering cavity and the seventh filtering cavity, and the seventh filtering cavity and the ninth filtering cavity of the third filtering branch are inductively and cross-coupled respectively to form four inductive cross-coupling zeros of the third filtering branch.

4. The filter of claim 3,

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

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

5. The filter of claim 4,

and the four inductive cross coupling zeros of the fourth filtering branch are formed by inductive cross coupling between the first filtering cavity and the third filtering cavity, between the third filtering cavity and the fifth filtering cavity, between the fifth filtering cavity and the seventh filtering cavity, and between the seventh filtering cavity and the ninth filtering cavity.

6. The filter of claim 5, further comprising:

the fifth filtering branch is arranged on the shell and consists of eleven filtering cavities which are sequentially coupled, and the eleven filtering cavities of the fifth filtering branch further form four cross-coupling zeros;

and the sixth filtering branch is arranged on the shell and consists of eleven filtering cavities which are sequentially coupled, and the eleven filtering cavities of the sixth filtering branch further form four cross-coupling zeros.

7. The filter of claim 6,

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

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

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

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

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

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

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

and the tenth filtering cavity and the eleventh filtering cavity of the fifth filtering branch are arranged in a crossed manner.

8. The filter of claim 7,

and the sixth filtering cavity and the eighth filtering cavity of the fifth filtering branch are inductively cross-coupled, and the third filtering cavity and the fifth filtering cavity, the sixth filtering cavity and the ninth filtering cavity, and the ninth filtering cavity and the eleventh filtering cavity are capacitively cross-coupled respectively to form four cross-coupling zeros of the fifth filtering branch.

9. The filter of claim 8,

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

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

the projection of the center of the sixth filtering cavity and the projection of the center of the eighth filtering cavity in the first direction are positioned between the center of the seventh filtering cavity and the projection of the center of the ninth filtering cavity in the first direction, and the projection of the center of the sixth filtering cavity and the projection of the center of the eighth filtering cavity in the second direction are positioned between the center of the seventh filtering cavity and the projection of the center of the ninth filtering cavity in the second direction;

the fourth filtering cavity, the ninth filtering cavity to the eleventh filtering cavity of the sixth filtering branch are arranged in a quadrilateral manner, the projection of the center of the ninth filtering cavity and the center of the tenth filtering cavity in the first direction is positioned between the projection of the center of the fourth filtering cavity and the projection of the center of the eleventh filtering cavity in the first direction, and 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 is positioned between the projection of the center of the fourth filtering cavity and the projection of the center of the eleventh filtering cavity in the second direction;

a tenth filtering cavity of the sixth filtering branch is respectively adjacent to a fourth filtering cavity, an eleventh filtering cavity and a tenth filtering cavity of the fourth filtering branch, and the tenth filtering cavity of the sixth filtering branch is intersected with the eleventh filtering cavity;

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

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

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

and the sixth filtering cavity and the eighth filtering cavity of the sixth filtering branch are inductively cross-coupled, and the third filtering cavity and the fifth filtering cavity, the sixth filtering cavity and the ninth filtering cavity, and the ninth filtering cavity and the eleventh filtering cavity are capacitively cross-coupled respectively, so as to form four cross-coupling zeros of the sixth filtering branch.

10. A communication system, comprising a terminal and a base station, wherein the base station comprises a base station antenna and a radio frequency unit connected to the base station antenna, and wherein the radio frequency unit comprises a filter according to any one of claims 1 to 9, and wherein the filter is configured to filter a radio frequency signal.