A filter and communication device

Abstract

The present application discloses a filter and a communication device. The filter includes: a housing having a first direction and a second direction perpendicular to each other; a first filter branch arranged on the housing, and composed of six filter cavities coupled in sequence along a first coupling path; a second filter branch arranged on the housing, and composed of five filter cavities coupled in sequence along a second coupling path, forming an inductive coupling zero point of the second filter branch; a third filter branch arranged on the housing, and composed of eight filter cavities coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch; a first common cavity arranged on the housing, and coupled with the first filter cavity of the first filter branch, the first filter cavity of the second filter branch, and the first filter cavity of the third filter branch, respectively. In this way, the volume of the filter can be reduced, the number of taps and welding points can be reduced, and the cost can be reduced; and the signal isolation between the filter branches of the filter can be improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a filter and a communication device. Background Art

[0002] In a base station system of mobile communication, a communication signal carrying communication data within a specific frequency range is usually transmitted through a transmitting antenna, and the communication signal is received through a receiving antenna. The signal received by the receiving antenna includes not only the communication signal carrying communication data within the above-mentioned specific frequency range, but also many clutter or interference signals outside the above-mentioned specific frequency range. To obtain the communication signal carrying communication data within the specific frequency range transmitted by the transmitting antenna from the signal received by the receiving antenna, it is usually necessary to filter the signal received by the receiving antenna through a filter to filter out clutter or interference signals outside the specific frequency of the communication signal carrying communication data.

[0003] The inventors of this application discovered during long-term research and development work that the volume and number of taps of existing filters will increase with the increase of filter branches, resulting in a large number of taps and welding points, high cost, and poor signal isolation between multiple filter branches of the filter. Summary of the invention

[0004] The present application provides a filter and a communication device to reduce the size of the filter, reduce the number of taps and welding points, reduce costs, and improve the signal isolation between filter branches of the filter.

[0005] In order to solve the above technical problems, a technical solution adopted by the present application is: to provide a filter. The filter includes: a housing, having a first direction and a second direction perpendicular to each other; a first filter branch, arranged on the housing, the first filter branch is composed of six filter cavities coupled in sequence along a first coupling path; a second filter branch, arranged on the housing, the second filter branch is composed of five filter cavities coupled in sequence along a second coupling path, forming an inductive coupling zero point of the second filter branch; a third filter branch, arranged on the housing, the third filter branch is composed of eight filter cavities coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch; a first common cavity, arranged on the housing, and coupled with the first filter cavity of the first filter branch, the first filter cavity of the second filter branch, and the first filter cavity of the third filter branch, respectively.

[0006] To solve the above technical problems, a technical solution adopted by the present application is to provide a communication device. The communication device includes an antenna and a radio frequency unit connected to the antenna, and the radio frequency unit includes the above filter for filtering radio frequency signals.

[0007] The beneficial effects of the embodiments of the present application are as follows: different from the prior art, the filter of the embodiments of the present application includes: a shell having a first direction and a second direction perpendicular to each other; a first filter branch arranged on the shell, the first filter branch consisting of six filter cavities coupled in sequence along a first coupling path; a second filter branch arranged on the shell, the second filter branch consisting of five filter cavities coupled in sequence along a second coupling path, forming an inductive coupling zero point of the second filter branch; a third filter branch arranged on the shell, the third filter branch consisting of eight filter cavities coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch; a first common cavity arranged on the shell, coupled with the first filter cavity of the first filter branch, the first filter cavity of the second filter branch and the first filter cavity of the third filter branch respectively. The first filter branch, the second filter branch and the third filter branch of the filter in the embodiment of the present application share the first common cavity, which can reduce the volume of the filter, and the first filter branch, the second filter branch and the third filter branch can be connected to the common port through the first common cavity, without the need to set ports for the first filter branch, the second filter branch and the third filter branch respectively. Therefore, the number of taps and tap welding points can be reduced, thereby reducing the cost of the filter; at the same time, the first filter branch has no coupling zero point, and the coupling zero point type of the second filter branch is different from the coupling zero point type of the third filter branch, thereby improving the signal isolation between the first filter branch, the second filter branch and the third filter branch. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0009] Figure 1 It is a structural schematic diagram of an embodiment of a filter of the present application;

[0010] Figure 2 It is a structural schematic diagram of an embodiment of a filter of the present application;

[0011] Figure 3 Schematic diagram of the topological structure of the first filter branch in an embodiment of the filter of the present application;

[0012] Figure 4 Schematic diagram of the topological structure of the second filter branch in the first embodiment of the filter of the present application;

[0013] Figure 5 Schematic diagram of the topological structure of the third filter branch in the first embodiment of the filter of the present application;

[0014] Figure 6 Schematic diagram of the topological structure of the eighth filter branch in the first embodiment of the filter of the present application;

[0015] Figure 7 It is a schematic diagram of simulation results of an embodiment of a filter of the present application;

[0016] Figure 8 It is a structural diagram of an embodiment of the communication device of the present application. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0018] The terms "first" and "second" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0019] This application first proposes a filter, such as Figure 1 , Figure 3 , Figure 4 and Figure 5 As shown, Figure 1 It is a structural schematic diagram of an embodiment of a filter of the present application; Figure 3 Schematic diagram of the topological structure of the first filter branch in an embodiment of the filter of the present application; Figure 4 Schematic diagram of the topological structure of the second filter branch in the first embodiment of the filter of the present application; Figure 5It is a schematic diagram of the topological structure of the third filter branch in an embodiment of the filter of the present application. The filter 10 of this embodiment includes: a housing 11, a first filter branch 12, a second filter branch 13, a third filter branch 14 and a first common cavity ABC, wherein the housing 11 has a first direction x and a second direction y perpendicular to each other; the first filter branch 12 is arranged on the housing 11, and is composed of six filter cavities A1-A6 coupled in sequence along a first coupling path; the second filter branch 13 is arranged on the housing 11, and is composed of five filter cavities B1-B5 coupled in sequence along a second coupling path, and the five filter cavities B1-B5 of the second filter branch 13 form an inductive coupling zero point of the second filter branch 13; the third filter branch 14 is arranged on the housing 11, and is composed of eight filter cavities C1-C8 coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch 14; the first common cavity ABC is arranged on the housing 11, and the first common cavity ABC is coupled with the first filter cavity A1 of the first filter branch 12, the first filter cavity B1 of the second filter branch 13 and the first filter cavity C1 of the third filter branch 14 respectively.

[0020] Among them, Figure 1 As shown, the six filter cavities A1-A6 of the first filter branch 12 include: a first filter cavity A1, a second filter cavity A2, a third filter cavity A3, a fourth filter cavity A4, a fifth filter cavity A5, and a sixth filter cavity A6; the five filter cavities B1-B5 of the second filter branch 13 include: a first filter cavity B1, a second filter cavity B2, a third filter cavity B3, a fourth filter cavity B4, and a fifth filter cavity B5; the eight filter cavities C1-C8 of the third filter branch 14 include: a first filter cavity C1, a second filter cavity C2, a third filter cavity C3, a fourth filter cavity C4, a fifth filter cavity C5, a sixth filter cavity C6, a seventh filter cavity C7, and an eighth filter cavity C8.

[0021] Different from the prior art, the first filter branch 12, the second filter branch 13 and the third filter branch 14 of the filter 10 of this embodiment share the first common cavity ABC, which can reduce the volume of the filter 10, and the first filter branch 12, the second filter branch 13 and the third filter branch 14 can be connected to the common port through the first common cavity ABC, without the need to set ports for the first filter branch 12, the second filter branch 13 and the third filter branch 14 respectively, therefore, the number of taps and tap welding points can be reduced, and the cost of the filter 10 can be reduced; at the same time, the first filter branch 12 has no coupling zero point, and the coupling zero point type of the second filter branch 13 is different from the coupling zero point type of the third filter branch 14, therefore, the signal isolation between the first filter branch 12, the second filter branch 13 and the third filter branch 14 can be improved.

[0022] Furthermore, the filter branches in the embodiments of the present application are all provided with coupling zero points, which can improve the out-of-band suppression and other characteristics of the signal of the filter branch.

[0023] Among them, the first filter branch 12 has no cross-coupling and adopts pure window coupling. The window coupling has good consistency and low cost, and there is no need to set other materials (such as inductive cross-coupling materials); the coupling zero points of the second filter branch 13 are all inductive coupling zero points, which can improve its material consistency and reduce its temperature drift; the coupling zero points of the third filter branch 14 are all capacitive coupling, which can improve its material consistency, simplify the process and save costs.

[0024] Alternatively, if Figure 1 As shown, the first filter cavity A1 to the sixth filter cavity A6 of the first filter branch 12 and the second filter cavity B2 to the fifth filter cavity B5 of the second filter branch 13 are divided into three columns arranged in sequence along the first direction x; the first filter cavity A1, the second filter cavity A2, the third filter cavity A3, and the fourth filter cavity A4 of the first filter branch 12 are in one column and are arranged adjacent to each other in sequence along the second direction y, the third filter cavity B3 and the fifth filter cavity B5 of the second filter branch 13, and the fifth filter cavity A5 and the sixth filter cavity A6 of the first filter branch 12 are in one column and are arranged adjacent to each other in sequence along the second direction y; and the first filter cavity A1 of the first filter branch 12 is also adjacent to the first common cavity ABC, the third filter cavity B3 of the second filter branch 13, and the fifth filter cavity B5 of the second filter branch 13, respectively.

[0025] From the above analysis, it can be seen that the first filter cavity A1 to the sixth filter cavity A6 of the first filter branch 12 and the second filter cavity B2 to the fifth filter cavity B5 of the second filter branch 13 are arranged in three columns, and the three columns of filter cavities are adjacent to each other, and the multiple filter cavities in each column are arranged adjacent to each other in sequence. The three columns of filter cavities are staggered, which can reduce the arrangement space of the first filter branch 12 and the second filter branch 13.

[0026] like Figure 1 As shown, the first common cavity ABC, the first filter cavity B1 of the second filter branch 13 and the first filter cavity C1 to the eighth filter cavity C8 of the third filter branch 14 are divided into two columns arranged in sequence along the first direction x; the first common cavity ABC and the first filter cavity C1, the second filter cavity C2, the third filter cavity C3, and the fourth filter cavity C4 of the third filter branch 14 are in one column and are arranged adjacent to each other in sequence along the second direction y; the first filter cavity B1 of the second filter branch 13 and the seventh filter cavity C7 to the fifth filter cavity C5 of the third filter branch 14 are in one column and are arranged adjacent to each other in sequence along the second direction y; and the first filter cavity C1 of the third filter branch 14 is also adjacent to the first filter cavity B1 of the second filter branch 13 and the eighth filter cavity C8 of the third filter branch 14, respectively.

[0027] From the above analysis, it can be seen that the first common cavity ABC, the first filter cavity B1 of the second filter branch 13 and the first filter cavity C1 to the eighth filter cavity C8 of the third filter branch 14 are arranged in two rows, and the two rows of filter cavities are adjacent to each other, and the multiple filter cavities in each row are arranged adjacent to each other in sequence. The two rows of filter cavities are staggered, which can reduce the arrangement space of the first common cavity ABC, the second filter branch 13 and the third filter branch 14.

[0028] The projection of the center of the first filter cavity A1 of the first filter branch 12 in the first direction x is located between the center of the first common cavity ABC and the projection of the center of the third filter cavity B3 of the second filter branch 13 in the first direction x, and the projection of the center of the first common cavity ABC in the second direction y is located between the center of the first filter cavity A1 of the first filter branch 12 and the projection of the center of the first filter cavity C1 of the third filter branch 14 in the second direction y.

[0029] From the above analysis, it can be seen that the first filter branch 12 and the second filter branch 13 are distributed along the first direction x, and the filter cavity in the first filter branch 12, the filter cavity in the second filter branch 13 and the filter cavity in the third filter branch 14 are all distributed along the first direction x; and the first filter branch 12, the first common cavity ABC and the third filter branch 14 are distributed along the second direction y, which can avoid the filter 10 being too large in the first direction x and the second direction y.

[0030] Furthermore, if Figure 1 As shown, the sizes of the six filter cavities A1-A6 of the first filter branch 12 are all the same. From the arrangement of the above filter cavities, it can be seen that the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the first filter branch 12 more compact and reduce the arrangement space of the first filter branch 12; the sizes of the five filter cavities B1-B5 of the second filter branch 13 are all the same, and the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the second filter branch 13 more compact and reduce the arrangement space of the second filter branch 13; the sizes of the eight filter cavities C1-C8 of the third filter branch 14 are all the same, and the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the third filter branch 14 more compact and reduce the arrangement space of the third filter branch 14.

[0031] Optionally, the topological structure of the first filter branch 12 is as follows: Figure 3 shown.

[0032] Alternatively, if Figure 1 As shown, the second filter cavity B2 of the second filter branch 13 is inductively cross-coupled with the fourth filter cavity B4 of the second filter branch 13 , forming an inductive coupling zero point of the second filter branch 13 .

[0033] The coupling zero point is also called the transmission zero point. The transmission zero point is when the filter transfer function is equal to zero, that is, at the frequency point corresponding to the transmission zero point, electromagnetic energy cannot pass through the network, thus playing a complete isolation role, suppressing the signal outside the passband, and better achieving high isolation between multiple passbands.

[0034] Generally speaking, the way to achieve the inductive coupling zero point is to use a window, and a metal coupling rib is set in the window. Figure 4 As shown, a window and a metal coupling rib (not shown, indicated by a dotted line) may be provided between the second filter cavity B2 and the fourth filter cavity B4. In this embodiment, inductive cross coupling is achieved through the metal coupling rib, and the metal coupling rib is less affected by changes in external temperature, thereby reducing the temperature drift of the second filter branch 13.

[0035] Alternatively, if Figure 1 As shown, capacitive cross coupling is formed between the third filter cavity C3 of the third filter branch 14 and the sixth filter cavity C6 of the third filter branch 14 , and between the fourth filter cavity C4 of the third filter branch 14 and the sixth filter cavity C6 of the third filter branch 14 , respectively, to form two capacitive coupling zero points of the third filter branch 14 .

[0036] Generally speaking, the way to achieve the capacitive coupling zero point is to use a capacitive cross-coupling element, and a general capacitive cross-coupling element can be a flying rod. Figure 5 As shown, flying rods (not shown, indicated by dotted lines) may be respectively arranged between the third filter cavity C3 and the sixth filter cavity C6 and between the fourth filter cavity C4 and the sixth filter cavity C6.

[0037] From the above analysis, it can be seen that the distance between the third filter cavity C3 and the sixth filter cavity C6, and the distance between the fourth filter cavity C4 and the sixth filter cavity C6 are equal. Two flying rods of the same model can be used to realize the two capacitive coupling zero points of the third filter branch 14. Therefore, it can improve the consistency of materials, simplify the process and save costs.

[0038] In another embodiment, if Figures 2 to 7 As shown, Figure 2 It is a structural schematic diagram of an embodiment of a filter of the present application; Figure 3 Schematic diagram of the topological structure of the first filter branch in an embodiment of the filter of the present application; Figure 4 Schematic diagram of the topological structure of the second filter branch in the first embodiment of the filter of the present application; Figure 5 Schematic diagram of the topological structure of the third filter branch in the first embodiment of the filter of the present application; Figure 6 Schematic diagram of the topological structure of the eighth filter branch in the first embodiment of the filter of the present application; Figure 7 It is a schematic diagram of simulation results of an embodiment of the filter of the present application.

[0039] like Figure 2 As shown, the filter 10 of this embodiment further includes: a fourth filter branch 15, a fifth filter branch 16 and a second common cavity DE on the basis of the above embodiment; wherein the fourth filter branch 15 is arranged on the housing 11, and the fourth filter branch 15 is composed of six filter cavities D1-D6 coupled in sequence along the fourth coupling path; the fifth filter branch 16 is arranged on the housing 11, and the fifth filter branch 16 is composed of five filter cavities E1-E5 coupled in sequence along the fifth coupling path, forming an inductive coupling zero point of the fifth filter branch 16; the second common cavity DE is arranged on the housing 11, and is coupled with the first filter cavity D1 of the fourth filter branch 15 and the first filter cavity E1 of the fifth filter branch 16 respectively.

[0040] Among them, Figure 2 As shown, the six filter cavities D1-D6 of the fourth filter branch 15 include: a first filter cavity D1, a second filter cavity D2, a third filter cavity D3, a fourth filter cavity D4, a fifth filter cavity D5 and a sixth filter cavity D6; the five filter cavities E1-E5 of the fifth filter branch 16 include: a first filter cavity E1, a second filter cavity E2, a third filter cavity E3, a fourth filter cavity E4, and a fifth filter cavity E5.

[0041] like Figure 2 As shown, the second common cavity DE, the first filter cavity D1 to the sixth filter cavity D6 of the fourth filter branch 15, and the first filter cavity E1 to the fifth filter cavity E5 of the fifth filter branch 16 are divided into four columns arranged in sequence along the first direction x; the fifth filter cavity D5 and the sixth filter cavity D6 of the fourth filter branch 15 are in one column and are arranged adjacent to each other in sequence along the second direction y, the third filter cavity D3 and the fourth filter cavity D4 of the fourth filter branch 15 are in one column and are arranged adjacent to each other in sequence along the second direction y, the second filter cavity D2 of the fourth filter branch 15 and the third filter cavity E3 of the fifth filter branch 16 are in one column and are arranged adjacent to each other in sequence along the second direction y. The second common cavity DE and the first filter cavity E1, the second filter cavity E2, the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 16 are arranged adjacent to each other in a row and are arranged adjacent to each other in sequence along the second direction y; the third filter cavity D3 of the fourth filter branch 15 is also adjacent to the fifth filter cavity D5 of the fourth filter branch 15, the second filter cavity D2 of the fourth filter branch 15 and the third filter cavity E3 of the fifth filter branch 16, respectively, and the second filter cavity E2 of the fifth filter branch 16 is also adjacent to the second filter cavity D2 of the fourth filter branch 15 and the third filter cavity E3 of the fifth filter branch 16, respectively.

[0042] From the above analysis, it can be seen that the second common cavity DE, the filter cavity of the fourth filter branch 15 and the filter cavity of the fifth filter branch 16 are arranged in four columns, and the four columns of filter cavities are adjacent to each other. The multiple filter cavities in each column are arranged adjacent to each other in sequence. The two columns of filter cavities are staggered, which can reduce the arrangement space of the second common cavity DE, the fourth filter branch 15 and the fifth filter branch 16.

[0043] Furthermore, if Figure 2 As shown, the sizes of the six filter cavities D1-D6 of the fourth filter branch 15 are all the same. From the arrangement of the above filter cavities, it can be seen that the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the fourth filter branch 15 more compact and reduce the arrangement space of the fourth filter branch 15; the sizes of the five filter cavities E1-E5 of the fifth filter branch 16 are all the same, and the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the fifth filter branch 16 more compact and reduce the arrangement space of the fifth filter branch 16.

[0044] Among them, the coupling zero point distribution and topological structure of the fourth filter branch 15 are the same as the topological structure of the first filter branch 12, which will not be repeated here; the coupling zero point distribution and topological structure of the fifth filter branch 16 are the same as the second filter branch 13, which will not be repeated here.

[0045] Alternatively, if Figure 2 As shown, the filter 10 further includes: a sixth filter branch 17, which is arranged on the housing 11, and the sixth filter branch 17 is composed of eight filter cavities F1-F8 coupled in sequence along a sixth coupling path, forming two capacitive coupling zero points of the sixth filter branch 17. The coupling zero points of the sixth filter branch 17 are all capacitive coupling zero points, which can improve the consistency of the material.

[0046] Among them, the eight filter cavities F1-F8 of the sixth filter branch 17 include: a first filter cavity F1, a second filter cavity F2, a third filter cavity F3, a fourth filter cavity F4, a fifth filter cavity F5, a sixth filter cavity F6, a seventh filter cavity F7, and an eighth filter cavity F8.

[0047] The third filter cavity F3 to the eighth filter cavity F8 of the sixth filter branch 17 are divided into four columns arranged in sequence along the first direction x; the fifth filter cavity F5, the sixth filter cavity F6 and the seventh filter cavity F7 of the sixth filter branch 17 are in one column and are arranged adjacent to each other in sequence along the second direction y, and the fourth filter cavity F4, the third filter cavity F3 and the eighth filter cavity F8 of the sixth filter branch 17 are in one column and are arranged adjacent to each other in sequence along the second direction y; the third filter cavity F3 of the sixth filter branch 17 is also respectively connected to the sixth filter cavity F6, the seventh filter cavity F7, the second filter cavity F2 and the first filter cavity D1 of the fourth filter branch 15 of the sixth filter branch 17 1, the second filter cavity F2 of the sixth filter branch 17 is also adjacent to the eighth filter cavity F8 and the first filter cavity F1, the second common cavity DE and the first filter cavity D1 of the fourth filter branch 15 of the sixth filter branch 17; the projections of the first filter cavity F1 and the second common cavity DE of the sixth filter branch 17 in the first direction x overlap, the second filter cavity F2 of the sixth filter branch 17 and the first filter cavity D1 of the fourth filter branch 15 in the first direction x overlap, and the fourth filter cavity F4 of the sixth filter branch 17 and the third filter cavity D3 of the fourth filter branch 15 in the first direction x overlap.

[0048] From the above analysis, it can be seen that the filter cavity of the sixth filter branch 17 is arranged in the same column and adjacent to the filter cavity of the fourth filter branch 14 , which can make the cavity arrangement more regular and reduce the volume of the filter 10 .

[0049] The coupling zero point distribution and topological structure of the sixth filter branch 17 are the same as those of the third filter branch 14, and are not described in detail here.

[0050] Alternatively, if Figure 2 As shown, the filter 10 also includes: a seventh filter branch 18, which is arranged on the shell 11, and the seventh filter branch 18 is composed of eight filter cavities G1-G8 coupled in sequence along the seventh coupling path, forming two capacitive coupling zero points of the seventh filter branch 18; the coupling zero points of the seventh filter branch 18 are all capacitive coupling zero points, which can improve the consistency of the material.

[0051] Among them, the eight filter cavities G1-G8 of the seventh filter branch 18 include: a first filter cavity G1, a second filter cavity G2, a third filter cavity G3, a fourth filter cavity G4, a fifth filter cavity G5, a sixth filter cavity G6, a seventh filter cavity G7, and an eighth filter cavity G8.

[0052] The first filter cavity G1 to the eighth filter cavity G8 of the seventh filter branch 18 are divided into four columns arranged in sequence along the first direction x; the first filter cavity G1 and the eighth filter cavity G8 of the seventh filter branch 18 are in one column and are arranged adjacent to each other in sequence along the second direction y, the second filter cavity G2 and the seventh filter cavity G7 of the seventh filter branch 18 are in one column and are arranged adjacent to each other in sequence along the second direction y, the third filter cavity G3 and the sixth filter cavity G6 of the seventh filter branch 18 are in one column and are arranged adjacent to each other in sequence along the second direction y, the fourth filter cavity G4 and the fifth filter cavity G5 of the seventh filter branch 18 are in one column and are arranged adjacent to each other in sequence along the second direction y; the seventh filter cavity G7 of the seventh filter branch 18 is also adjacent to the first filter cavity G1, the eighth filter cavity G8, the third filter cavity G3 and the sixth filter cavity G6 of the seventh filter branch 18, respectively, and the fourth filter cavity G4 of the seventh filter branch 18 is also adjacent to the seventh filter cavity C7 and the sixth filter cavity C6 of the third filter branch 14.

[0053] The eight filter cavities G1 - G8 of the seventh filter branch 18 are arranged in multiple rows, which can make the cavity arrangement more regular and reduce the arrangement space. The seventh filter branch 18 is arranged adjacent to the third filter branch 14 , which can reduce the volume of the filter 10 .

[0054] The coupling zero point distribution and topological structure of the seventh filter branch 18 are the same as those of the third filter branch 14, and are not described in detail here.

[0055] Alternatively, if Figure 2 As shown, the filter 10 also includes: an eighth filter branch 19, which is arranged on the shell 11, and the eighth filter branch 19 is composed of eight filter cavities H1-H8 coupled in sequence along an eighth coupling path, forming two capacitive coupling zero points of the eighth filter branch 19; the coupling zero points of the eighth filter branch 19 are all capacitive coupling zero points, which can improve the consistency of the material.

[0056] Among them, the eight filter cavities H1-H8 of the eighth filter branch 19 include: a first filter cavity H1, a second filter cavity H2, a third filter cavity H3, a fourth filter cavity H4, a fifth filter cavity H5, a sixth filter cavity H6, a seventh filter cavity H7, and an eighth filter cavity H8.

[0057] The second filter cavity H2 to the sixth filter cavity H6 of the eighth filter branch 19 are divided into two columns arranged in sequence along the first direction x; the second filter cavity H2, the third filter cavity H3 and the fourth filter cavity H4 of the eighth filter branch 19 are in one column and are arranged adjacent to each other in sequence along the second direction y, the sixth filter cavity H6 and the fifth filter cavity H5 of the eighth filter branch 19 are in one column and are arranged adjacent to each other in sequence along the second direction y; the third filter cavity H3 of the eighth filter branch 19 is also adjacent to the fifth filter cavity H5 and the sixth filter cavity H6 of the eighth filter branch 19 and the fifth filter cavity E5 of the fifth filter branch 16, respectively; the fifth filter cavity H5 of the eighth filter branch 19 is also adjacent to the fourth filter cavity H4 of the eighth filter branch 19 and the fourth filter cavity D4 and the sixth filter cavity D6 of the fourth filter branch 15; the fourth filter cavity H4 of the eighth filter branch 19 overlaps with the projection of the third filter cavity E3 of the fifth filter branch 16 in the first direction x, and the eighth filter branch 19 The fifth filter cavity H5 overlaps with the projection of the fourth filter cavity D4 of the fourth filter branch 15 in the first direction x; the first filter cavity H1, the second filter cavity H2, the sixth filter cavity H6, the seventh filter cavity H7 and the eighth filter cavity H8 of the eighth filter branch 19 are arranged adjacent to each other in sequence, and the distances between the projections of the centers of the second filter cavity H2, the sixth filter cavity H6, the seventh filter cavity H7 and the eighth filter cavity H8 of the eighth filter branch 19 in the first direction x and the projection of the center of the first filter cavity H1 of the eighth filter branch 19 in the first direction x gradually increase; the projections of the seventh filter cavity H7 and the eighth filter cavity H8 of the eighth filter branch 19 in the second direction y overlap, and the projection of the center of the second filter cavity H2 of the eighth filter branch 19 in the second direction y is located between the projections of the center of the first filter cavity H1 of the eighth filter branch 19 and the center of the third filter cavity H3 of the eighth filter branch 19 in the second direction y.

[0058] From the above analysis, it can be seen that the filter cavity of the eighth filter branch 19 is arranged in the same column and adjacent to the filter cavity of the fourth filter branch 14 and the filter cavity of the fifth filter branch 16, which can make the cavity arrangement more regular and reduce the volume of the filter 10.

[0059] Furthermore, if Figure 2 As shown, the eight filter cavities H1-H8 of the eighth filter branch 19 have the same size. From the arrangement of the above filter cavities, it can be seen that the distance between the centers of any two adjacent filter cavities is equal, which can make the arrangement of the eighth filter branch 19 more compact and reduce the arrangement space of the eighth filter branch 19.

[0060] like Figure 2As shown, the third filter cavity H3 of the eighth filter branch 19 and the fifth filter cavity H5 of the eighth filter branch 19 and the third filter cavity H3 of the eighth filter branch 19 and the sixth filter cavity H6 of the eighth filter branch 19 are capacitively cross-coupled to form two capacitive coupling zero points of the eighth filter branch 19.

[0061] like Figure 6 As shown, flying rods (not shown, indicated by dotted lines) may be respectively arranged between the third filter cavity H3 and the fifth filter cavity H5 and between the third filter cavity H3 and the sixth filter cavity H6.

[0062] From the above analysis, it can be seen that the distance between the third filter cavity H3 and the fifth filter cavity H5, and the distance between the third filter cavity H3 and the sixth filter cavity H6 are equal. Two flying rods of the same model can be used to realize the two capacitive coupling zero points of the eighth filter branch 19. Therefore, it can improve the consistency of materials, simplify the process and save costs.

[0063] Optionally, the seventh filter branch 18 is arranged adjacent to the third filter branch 14 along the first direction x; the first filter branch 12, the second filter branch 13, the third filter branch 14 and the seventh filter branch 18 are arranged in a first area of ​​the shell 11 (not marked in the figure), the fourth filter branch 15, the fifth filter branch 16, the sixth filter branch 17 and the eighth filter branch 18 are arranged in a second area of ​​the shell 11 (not marked in the figure), and the first area and the second area are arranged at intervals; an input / output port can be set in the interval area between the first area and the second area to reduce the length of the tap.

[0064] Furthermore, if Figure 2 As shown, the housing 11 is further provided with: a first input port (not marked in the figure), connected to the first common cavity ABC; a second input port (not marked in the figure), connected to the second common cavity DE; a third input port (not marked in the figure), connected to the first filter cavity F1 of the sixth filter branch 17; a fourth input port (not marked in the figure), connected to the first filter cavity G1 of the seventh filter branch 18; a fifth input port (not marked in the figure), connected to the first filter cavity H1 of the eighth filter branch 19; a first output port (not marked in the figure) to an eighth output port (not marked in the figure), respectively connected to the sixth filter cavity A6 of the first filter branch 12, the fifth filter cavity B5 of the second filter branch 13, the eighth filter cavity C8 of the third filter branch 14, the sixth filter cavity D6 of the fourth filter branch 15, the fifth filter cavity E5 of the fifth filter branch 16, the eighth filter cavity F8 of the sixth filter branch 17, the eighth filter cavity G8 of the seventh filter branch 18, and the eighth filter cavity H8 of the eighth filter branch 19.

[0065] The above ports are used for filtering signal transmission; the above ports can all be taps.

[0066] like Figure 2 As shown, in the first filter branch 12, the coupling bandwidth range between the first input port of this embodiment and the first filter cavity A1 is 129MHz-133MHz; the coupling bandwidth range between the first filter cavity A1 and the second filter cavity A2 is 108MHz112MHz; the coupling bandwidth range between the second filter cavity A2 and the third filter cavity A3 is 77MHz-81MHz; the coupling bandwidth range between the third filter cavity A3 and the fourth filter cavity A4 is 74MHz-78MHz; the coupling bandwidth range between the fourth filter cavity A4 and the fifth filter cavity A5 is 77MHz-81MHz; the coupling bandwidth range between the fifth filter cavity A5 and the sixth filter cavity A6 is 108MHz112MHz; the coupling bandwidth range between the sixth filter cavity A6 and the first output port is 129MHz-133MHz, which can meet the design requirements.

[0067] Among them, the resonant frequencies of the first filter cavity A1 to the sixth filter cavity A6 of the first filter branch 12 are respectively in the following ranges: 2348MHz-2350MHz, 2348MHz-2350MHz, 2348MHz-2350MHz, 2348MHz-2350MHz, 2348MHz-2350MHz, 2348MHz-2350MHz, 2348MHz-2350MHz.

[0068] It can be seen that the resonant frequencies of the various filter cavities are the same, which improves the convenience of manufacturing and debugging; that is, the same specification parameters can be used for manufacturing, and only simple debugging is needed in the actual process to achieve the required parameter range.

[0069] like Figure 2 As shown, in the second filter branch 13, the coupling bandwidth range between the first input port of this embodiment and the first filter cavity B1 is 180MHz-184MHz; the coupling bandwidth range between the first filter cavity B1 and the second filter cavity B2 is 151MHz-155MHz; the coupling bandwidth range between the second filter cavity B2 and the third filter cavity B3 is 92MHz-96MHz; the coupling bandwidth range between the second filter cavity B2 and the fourth filter cavity B4 is 61MHz-65MHz; the coupling bandwidth range between the third filter cavity B3 and the fourth filter cavity B4 is 92MHz-96MHz; the coupling bandwidth range between the fourth filter cavity B4 and the fifth filter cavity B5 is 151MHz-155MHz; the coupling bandwidth range between the fifth filter cavity B5 and the second output port is 180MHz-184MHz, which can meet the design requirements.

[0070] Among them, the resonant frequencies of the first filter cavity B1 to the fifth filter cavity B5 of the second filter branch 13 are respectively within the following ranges: 1789MHz-1791MHz, 1788MHz-1790MHz, 1845MHz-1847MHz, 1788MHz-1790MHz, 1789MHz-1791MHz.

[0071] It can be seen that the resonant frequencies of the various filter cavities are basically the same, which improves the convenience of manufacturing and debugging; that is, the same specification parameters can be used for manufacturing, and only simple debugging is needed in the actual process to achieve the required parameter range.

[0072] like Figure 2 As shown, in the third filter branch 14, the coupling bandwidth range between the first input port of this embodiment and the first filter cavity C1 is 158MHz-162MHz; the coupling bandwidth range between the first filter cavity C1 and the second filter cavity C2 is 132MHz-136MHz; the coupling bandwidth range between the second filter cavity C2 and the third filter cavity C3 is 94MHz-98MHz; the coupling bandwidth range between the third filter cavity C3 and the fourth filter cavity C4 is 84MHz-88MHz; the coupling bandwidth range between the third filter cavity C3 and the sixth filter cavity C6 is (-27)MHz-(-23)MHz; the coupling bandwidth range between the fourth filter cavity C4 and the fifth filter cavity C The coupling bandwidth range between the fourth filter cavity C4 and the sixth filter cavity C6 is 104MHz-108MHz; the coupling bandwidth range between the fifth filter cavity C5 and the sixth filter cavity C6 is 80MHz-84MHz; the coupling bandwidth range between the sixth filter cavity C6 and the seventh filter cavity C7 is 94MHz-98MHz; the coupling bandwidth range between the seventh filter cavity C7 and the eighth filter cavity C8 is 132MHz-136MHz; the coupling bandwidth range between the eighth filter cavity C8 and the third output port is 158MHz-162MHz, which can meet the design requirements.

[0073] Among them, the resonant frequencies of the first filter cavity C1 to the eighth filter cavity C8 of the third filter branch 14 are respectively in the following ranges: 2593MHz-2595MHz, 2593MHz-2595MHz, 2593MHz-2595MHz, 2601MHz-2603MHz, 2567MHz-2569MHz, 2593MHz-2595MHz, 2593MHz-2595MHz, 2593MHz-2595MHz, 2593MHz-2595MHz.

[0074] It can be seen that the resonant frequencies of the various filter cavities are basically the same, which improves the convenience of manufacturing and debugging; that is, the same specification parameters can be used for manufacturing, and only simple debugging is needed in the actual process to achieve the required parameter range.

[0075] like Figure 7 As shown, the bandwidth of the first filter branch 12 is within the range of 2299MHz-2301MHz, and its frequency band curve is shown in S1. The suppression of the first filter branch 12 satisfies: 9KHz-960MHz is greater than or equal to 40dB, 1710MHz-1880MHz is greater than or equal to 25dB, 1920MHz-2170MHz is greater than or equal to 25dB, 2496MHz-2690MHz is greater than or equal to 25dB, and 3400MHz-3800MHz is greater than or equal to 25dB.

[0076] The bandwidth of the second filter branch 13 is within the range of 1709MHz-1881MHz, and its frequency band curve is shown in S2. The suppression of the second filter branch 13 satisfies: 9KHz-960MHz is greater than or equal to 40dB, 1920MHz-2170MHz is greater than or equal to 25dB, 2300MHz-2690MHz is greater than or equal to 25dB, and 3400MHz-3800MHz is greater than or equal to 25dB.

[0077] The bandwidth of the third filter branch 14 is within the range of 2514MHz-2676MHz, and its band curve is shown in S3. The suppression of the third filter branch 14 satisfies: 9KHz-960MHz is greater than or equal to 40dB, 1710MHz-1880MHz is greater than or equal to 25dB, 1920MHz-2170MHz is greater than or equal to 25dB, 2483.5MHz-2500MHz is greater than or equal to 28dB, 2700MHz-2900MHz is greater than or equal to 25dB, and 3400MHz-3800MHz is greater than or equal to 25dB.

[0078] It can be seen that the bandwidths of the first filter branch 12 , the second filter branch 13 and the third filter branch 14 are different, and the signal isolation is relatively high.

[0079] The above-mentioned RF parameters and simulation results of the fourth filter branch 15 are the same as those of the first filter branch 12, the above-mentioned RF parameters and simulation results of the fifth filter branch 16 are the same as those of the second filter branch 13, and the above-mentioned RF parameters and simulation results of the sixth filter branch 17 and the seventh filter branch 18 are the same as those of the third filter branch 14, which will not be repeated here.

[0080] It should be noted that the parameters (such as frequency and suppression) of two or more coupling zero points of the present application may be the same; in the simulation diagram, coupling zero points with the same parameters are displayed as the same coupling zero point.

[0081] Some implementations of the present application are called filters, and may also be called duplexers or combiners.

[0082] The present application also provides a communication device, such as Figure 8 As shown, Figure 8 The communication device of this embodiment includes an antenna 32 and a radio frequency unit 31 connected to the antenna 32. The radio frequency unit 31 includes the filter 10 shown in the above embodiment. The filter 10 is used to filter the radio frequency signal.

[0083] In other implementation examples, the radio frequency unit 31 may also be integrated with the antenna 32 to form an active antenna unit (AAU).

[0084] Different from the prior art, the filter in the embodiment of the present application includes: a shell having a first direction and a second direction perpendicular to each other; a first filter branch, arranged on the shell, the first filter branch consists of six filter cavities coupled in sequence along a first coupling path; a second filter branch, arranged on the shell, the second filter branch consists of five filter cavities coupled in sequence along a second coupling path, forming an inductive coupling zero point of the second filter branch; a third filter branch, arranged on the shell, the third filter branch consists of eight filter cavities coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch; a first common cavity, arranged on the shell, coupled with the first filter cavity of the first filter branch, the first filter cavity of the second filter branch and the first filter cavity of the third filter branch respectively. The first filter branch, the second filter branch and the third filter branch of the filter in the embodiment of the present application share the first common cavity, which can reduce the volume of the filter, and the first filter branch, the second filter branch and the third filter branch can be connected to the common port through the first common cavity, without the need to set ports for the first filter branch, the second filter branch and the third filter branch respectively. Therefore, the number of taps and tap welding points can be reduced, thereby reducing the cost of the filter; at the same time, the first filter branch has no coupling zero point, and the coupling zero point type of the second filter branch is different from the coupling zero point type of the third filter branch, thereby improving the signal isolation between the first filter branch, the second filter branch and the third filter branch.

[0085] The above description is only an implementation method of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A filter, It is characterized in that The filter comprises: The housing has a first direction and a second direction perpendicular to each other; A first filter branch is arranged on the housing, wherein the first filter branch is composed of six filter cavities coupled in sequence along a first coupling path; A second filter branch is arranged on the housing, the second filter branch is composed of five filter cavities coupled in sequence along a second coupling path, forming an inductive coupling zero point of the second filter branch; A third filter branch is arranged on the housing, the third filter branch is composed of eight filter cavities coupled in sequence along a third coupling path, forming two capacitive coupling zero points of the third filter branch; A first common cavity is arranged on the housing and is respectively coupled with the first filter cavity of the first filter branch, the first filter cavity of the second filter branch, and the first filter cavity of the third filter branch; Among them, the first filter cavity to the sixth filter cavity of the first filter branch and the second filter cavity to the fifth filter cavity of the second filter branch are divided into three columns arranged in sequence along the first direction; the first filter cavity, the second filter cavity, the third filter cavity, and the fourth filter cavity of the first filter branch are in one column and are arranged adjacent to each other in sequence along the second direction, the third filter cavity and the fifth filter cavity of the second filter branch, and the fifth filter cavity and the sixth filter cavity of the first filter branch are in one column and are arranged adjacent to each other in sequence along the second direction; and the first filter cavity of the first filter branch is also arranged adjacent to the first common cavity, the third filter cavity of the second filter branch, and the fifth filter cavity of the second filter branch respectively; the first common cavity, the first filter cavity of the second filter branch, and the first filter cavity to the eighth filter cavity of the third filter branch are divided into two columns arranged in sequence along the first direction; The first common cavity, the first filter cavity to the fourth filter cavity of the third filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; the first filter cavity of the second filter branch and the seventh filter cavity to the fifth filter cavity of the third filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; and the first filter cavity of the third filter branch is also arranged adjacent to the first filter cavity of the second filter branch and the eighth filter cavity of the third filter branch respectively; the projection of the center of the first filter cavity of the first filter branch in the first direction is located between the center of the first common cavity and the projection of the center of the third filter cavity of the second filter branch in the first direction, and the projection of the center of the first common cavity in the second direction is located between the center of the first filter cavity of the first filter branch and the projection of the center of the first filter cavity of the third filter branch in the second direction; Wherein, an inductive cross-coupling is formed between the second filter cavity of the second filter branch and the fourth filter cavity of the second filter branch, forming an inductive coupling zero point of the second filter branch; a capacitive cross-coupling is formed between the third filter cavity of the third filter branch and the sixth filter cavity of the third filter branch, and between the fourth filter cavity of the third filter branch and the sixth filter cavity of the third filter branch, respectively, forming two capacitive coupling zero points of the third filter branch; Wherein, the filter further comprises: a fourth filter branch, which is arranged on the housing, and the fourth filter branch is composed of six filter cavities coupled in sequence along a fourth coupling path; a fifth filter branch, which is arranged on the housing, and the fifth filter branch is composed of five filter cavities coupled in sequence along a fifth coupling path, forming an inductive coupling zero point of the fifth filter branch; A second common cavity is arranged on the housing and is coupled with the first filter cavity of the fourth filter branch and the first filter cavity of the fifth filter branch respectively; Among them, the six filter cavities of the first filter branch have the same size, the five filter cavities of the second filter branch have the same size, the eight filter cavities of the third filter branch have the same size, and the distance between the centers of any two adjacent filter cavities is equal.

2. The filter according to claim 1, It is characterized in that The second common cavity, the first filter cavity to the sixth filter cavity of the fourth filter branch, and the first filter cavity to the fifth filter cavity of the fifth filter branch are divided into four columns arranged in sequence along the first direction; The fifth filter cavity and the sixth filter cavity of the fourth filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; the third filter cavity and the fourth filter cavity of the fourth filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; the second filter cavity of the fourth filter branch and the third filter cavity of the fifth filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; the second common cavity and the first filter cavity, the second filter cavity, the fourth filter cavity and the fifth filter cavity of the fifth filter branch are in a row and are arranged adjacent to each other in sequence along the second direction; The third filter cavity of the fourth filter branch is also arranged adjacent to the fifth filter cavity of the fourth filter branch, the second filter cavity of the fourth filter branch and the third filter cavity of the fifth filter branch, respectively; the second filter cavity of the fifth filter branch is also arranged adjacent to the second filter cavity of the fourth filter branch and the third filter cavity of the fifth filter branch, respectively; The coupling zero point distribution of the fifth filter branch is the same as the coupling zero point distribution of the second filter branch.

3. The filter according to claim 2, It is characterized in that The filter further comprises: A sixth filter branch is arranged on the housing, the sixth filter branch is composed of eight filter cavities coupled in sequence along a sixth coupling path, forming two capacitive coupling zero points of the sixth filter branch; The third filter cavity to the eighth filter cavity of the sixth filter branch are divided into four columns arranged in sequence along the first direction; the fifth filter cavity, the sixth filter cavity and the seventh filter cavity of the sixth filter branch are in one column and are arranged adjacent to each other in sequence along the second direction; the fourth filter cavity, the third filter cavity and the eighth filter cavity of the sixth filter branch are in one column and are arranged adjacent to each other in sequence along the second direction; the third filter cavity of the sixth filter branch is also arranged adjacent to the sixth filter cavity, the seventh filter cavity, the second filter cavity of the sixth filter branch and the first filter cavity of the fourth filter branch respectively; the second filter cavity of the sixth filter branch is also arranged adjacent to the eighth filter cavity and the first filter cavity of the sixth filter branch, the second common cavity and the first filter cavity of the fourth filter branch; the projection of the first filter cavity of the sixth filter branch overlaps with the projection of the second common cavity in the first direction, the second filter cavity of the sixth filter branch overlaps with the projection of the first filter cavity of the fourth filter branch in the first direction, and the fourth filter cavity of the sixth filter branch overlaps with the projection of the third filter cavity of the fourth filter branch in the first direction; The coupling zero point distribution of the sixth filter branch is the same as the coupling zero point distribution of the third filter branch.

4. The filter according to claim 3, It is characterized in that The filter further comprises: A seventh filter branch is arranged on the housing, the seventh filter branch is composed of eight filter cavities coupled in sequence along a seventh coupling path, forming two capacitive coupling zero points of the seventh filter branch; The first filter cavity to the eighth filter cavity of the seventh filter branch are divided into four columns arranged in sequence along the first direction; the first filter cavity and the eighth filter cavity of the seventh filter branch are in one column and are arranged adjacent to each other in sequence along the second direction, the second filter cavity and the seventh filter cavity of the seventh filter branch are in one column and are arranged adjacent to each other in sequence along the second direction, the third filter cavity and the sixth filter cavity of the seventh filter branch are in one column and are arranged adjacent to each other in sequence along the second direction, the fourth filter cavity and the fifth filter cavity of the seventh filter branch are in one column and are arranged adjacent to each other in sequence along the second direction; the seventh filter cavity of the seventh filter branch is also arranged adjacent to the first filter cavity, the eighth filter cavity, the third filter cavity and the sixth filter cavity of the seventh filter branch respectively, and the fourth filter cavity of the seventh filter branch is also arranged adjacent to the seventh filter cavity and the sixth filter cavity of the third filter branch; The coupling zero point distribution of the seventh filter branch is the same as the coupling zero point distribution of the third filter branch.

5. The filter according to claim 4, It is characterized in that The filter further comprises: An eighth filter branch is arranged on the housing, the eighth filter branch is composed of eight filter cavities coupled in sequence along an eighth coupling path, forming two capacitive coupling zero points of the eighth filter branch; The second filter cavity to the sixth filter cavity of the eighth filter branch are divided into two columns arranged in sequence along the first direction; the second filter cavity, the third filter cavity and the fourth filter cavity of the eighth filter branch are in one column and are arranged adjacent to each other in sequence along the second direction, and the sixth filter cavity and the fifth filter cavity of the eighth filter branch are in one column and are arranged adjacent to each other in sequence along the second direction; the third filter cavity of the eighth filter branch is also arranged adjacent to the fifth filter cavity and the sixth filter cavity of the eighth filter branch and the fifth filter cavity of the fifth filter branch respectively, and the fifth filter cavity of the eighth filter branch is also arranged adjacent to the fourth filter cavity of the eighth filter branch and the fourth filter cavity and the sixth filter cavity of the fourth filter branch; the fourth filter cavity of the eighth filter branch overlaps with the projection of the third filter cavity of the fifth filter branch in the first direction, and the fifth filter cavity of the eighth filter branch overlaps with the projection of the fourth filter cavity of the fourth filter branch in the first direction; The first filter cavity, the second filter cavity, the sixth filter cavity, the seventh filter cavity and the eighth filter cavity of the eighth filter branch are arranged adjacent to each other in sequence, and the distances between the projections of the centers of the second filter cavity, the sixth filter cavity, the seventh filter cavity and the eighth filter cavity of the eighth filter branch in the first direction and the projections of the center of the first filter cavity of the eighth filter branch in the first direction gradually increase; the projections of the seventh filter cavity and the eighth filter cavity of the eighth filter branch in the second direction overlap, and the projection of the center of the second filter cavity of the eighth filter branch in the second direction is located between the projections of the center of the first filter cavity of the eighth filter branch and the center of the third filter cavity of the eighth filter branch in the second direction; The third filter cavity of the eighth filter branch and the fifth filter cavity of the eighth filter branch and the third filter cavity of the eighth filter branch and the sixth filter cavity of the eighth filter branch are capacitively cross-coupled to form two capacitive coupling zero points of the eighth filter branch.

6. The filter according to claim 5, It is characterized in that The seventh filter branch and the third filter branch are arranged adjacent to each other along the first direction; The first filter branch, the second filter branch, the third filter branch and the seventh filter branch are arranged in a first area of ​​the shell, the fourth filter branch, the fifth filter branch, the sixth filter branch and the eighth filter branch are arranged in a second area of ​​the shell, and the first area and the second area are arranged at intervals.

7. A communication device, It is characterized in that The communication device comprises an antenna and a radio frequency unit connected to the antenna, wherein the radio frequency unit comprises the filter according to any one of claims 1 to 6, and is used to filter radio frequency signals.

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