CN113054381A

CN113054381A - Communication device and filter thereof

Info

Publication number: CN113054381A
Application number: CN201911383531.2A
Authority: CN
Inventors: 周峰; 温世议; 龚爱强; 韩军平
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 device and a filter thereof. The filter includes: a housing having a first direction and a second direction perpendicular to each other; the first filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled; the second filtering branch consists of eight filtering cavities which are coupled in sequence; the eight filter cavities of the first filter branch circuit, the eighth filter cavity and the eighth filter cavity are divided into four rows arranged along the second direction, and the projections of the first filter branch circuit and the second filter branch circuit in the second direction are at least partially overlapped. By the mode, the filter window coupling consistency is good, the product complexity is reduced, the stability of the filter is improved, the size of the filter can be reduced, and the miniaturization of the filter is facilitated.

Description

Communication device and filter thereof

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication device 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 existing filter is provided with capacitive cross coupling or inductive cross coupling, the types of materials required by the filter are various, the product complexity is high, and the window coupling consistency is poor.

Disclosure of Invention

In order to solve the above problems of the prior art filter, the present application provides a communication device and a filter thereof.

To solve the above problem, an embodiment of the present application provides a filter, including: a housing having a first direction and a second direction perpendicular to each other; the first filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled; the second filtering branch consists of eight filtering cavities which are coupled in sequence; the eight filter cavities of the first filter branch circuit, the eighth filter cavity and the eighth filter cavity are divided into four rows arranged along the second direction, and the projections of the first filter branch circuit and the second filter branch circuit in the second direction are at least partially overlapped.

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

Different from the situation of the prior art, in the application, the first filtering branch and the second filtering branch can be pure window coupling, the consistency of the window coupling is good, the cost is low, and other materials are not required to be arranged; in addition, the filter cavities of the first filter branch and the second filter branch are regularly arranged, and at least part of projections in the second direction are overlapped, so that the filter cavities are arranged more closely, the size of the filter is reduced, and the miniaturization of the filter is facilitated.

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 structural diagram of a first embodiment of a filter provided in the present application;

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

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

fig. 4 is a schematic diagram illustrating simulation results of an embodiment of a first filtering branch provided in the present application;

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

FIG. 6 is a schematic diagram of a topology of an embodiment of a fourth filtering branch provided in the present application;

fig. 7 is a schematic diagram illustrating simulation results of another embodiment of the first filtering branch provided in the present application;

FIG. 8 is a schematic diagram of a second embodiment of a filter provided herein;

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

FIG. 10 is a schematic topology diagram of another embodiment of a second filtering branch provided in the present application;

FIG. 11 is a schematic topology diagram of another embodiment of a third filtering branch provided herein;

FIG. 12 is a schematic topology diagram of another embodiment of a fourth filtering branch provided in the present application;

fig. 13 is a diagram illustrating simulation results of a further embodiment of the first filtering branch provided in the present application;

FIG. 14 is a diagram illustrating simulation results of yet another embodiment of the first filtering branch provided in the present application;

FIG. 15 is a schematic diagram of a third embodiment of a filter provided herein;

FIG. 16 is a schematic topology diagram of an embodiment of a fifth filtering branch provided in the present application;

FIG. 17 is a schematic topology diagram of an embodiment of a sixth filtering branch provided in the present application;

FIG. 18 is a diagram illustrating simulation results of an embodiment of a fifth filtering branch provided in the present application;

FIG. 19 is a schematic diagram of a topology of an embodiment of a seventh filtering branch provided in the present application;

FIG. 20 is a schematic diagram of a topology of an embodiment of an eighth filtering branch provided in the present application;

fig. 21 is a diagram illustrating simulation results of another embodiment of a fifth filtering branch provided in the present application;

FIG. 22 is a schematic diagram of a fourth embodiment of a filter provided herein;

FIG. 23 is a schematic topology diagram of another embodiment of a fifth filtering branch provided in the present application;

FIG. 24 is a schematic topology diagram of another embodiment of a sixth filtering branch provided herein;

FIG. 25 is a schematic topology diagram of another embodiment of a seventh filtering branch provided by the present application;

FIG. 26 is a schematic topology diagram of another embodiment of an eighth filtering branch provided in the present application;

FIG. 27 is a diagram illustrating simulation results of yet another embodiment of a fifth filtering branch provided in the present application;

fig. 28 is a schematic structural diagram of a fifth embodiment of the filter provided in the present application;

FIG. 29 is a schematic topology diagram of yet another embodiment of a fifth filtering branch provided by the present application;

FIG. 30 is a schematic topology diagram of yet another embodiment of a sixth filtering branch provided by the present application;

fig. 31 is a schematic structural diagram of a sixth embodiment of a filter provided in the present application;

fig. 32 is a schematic structural diagram of an embodiment of a communication device provided in the present application.

Detailed Description

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

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

The present application provides a filter, as shown in fig. 1, fig. 1 is a schematic structural diagram of a first embodiment of the filter provided in the present application. The filter 10 of the present embodiment includes a housing 11, a first filter branch 121, and a second filter branch 122. The first filtering branch 121 and the second filtering branch 122 may be a transmitting filtering branch or a receiving filtering branch.

The first filtering branch 121 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the first filtering branch 121 are specifically a first filtering cavity a1, a second filtering cavity a2, a third filtering cavity A3, a third filtering cavity a4, a fifth filtering cavity a5, a sixth filtering cavity a6, a seventh filtering cavity a7 and an eighth filtering cavity A8 of the first filtering branch 121.

The second filtering branch 122 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the second filtering branch 122 are specifically a first filtering cavity B1, a second filtering cavity B2, a third filtering cavity B3, a third filtering cavity B4, a fifth filtering cavity B5, a sixth filtering cavity B6, a seventh filtering cavity B7 and an eighth filtering cavity B8 of the second filtering branch 122.

The housing 11 has a first direction L and a second direction D perpendicular to the first direction L, the first direction L may be a length direction of the housing 11, and the second direction D may be a width direction of the housing 11. As shown in fig. 1, the projections of the first filtering branch 121 and the second filtering branch 122 in the second direction D at least partially coincide, and the second filtering cavity a2 to the eighth filtering cavity A8 of the first filtering branch 121 and the first filtering cavity B1 to the eighth filtering cavity B8 of the second filtering branch 122 are divided into four columns arranged along the second direction D.

Specifically, the first filter cavity B1, the second filter cavity B2, the third filter cavity B3 and the eighth filter cavity B8 of the second filter branch 122 are in a row and are sequentially arranged along the first direction L; the third filtering cavity A3, the fourth filtering cavity a4 of the first filtering branch 121, and the fourth filtering cavity B4 and the seventh filtering cavity B7 of the second filtering branch 122 are in a row and are sequentially arranged along the first direction L; the second filtering cavity a2 and the fifth filtering cavity a5 of the first filtering branch 121, and the fifth filtering cavity B5 and the sixth filtering cavity B6 of the second filtering branch 122 are in a row and are sequentially arranged along the first direction L; the sixth filtering cavity a6, the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 121 are in a row and are sequentially arranged along the first direction L. Wherein, the projection of the center of the first filter cavity a1 of the first filter branch 121 in the second direction D is located between the center of the second filter cavity a2 of the first filter branch 121 and the projection of the center of the sixth filter cavity a6 in the second direction D, and the projection of the center of the second filter cavity a2 of the first filter branch 121 in the first direction L is located between the center of the a1 of the first filter cavity of the first filter branch 121 and the projection of the center of the sixth filter cavity a6 in the first direction L. The cavity is regularly arranged in the filter 10, the cavity space can be fully utilized, the miniaturization of the filter 10 is facilitated, and the layout and debugging are facilitated.

The fifth filtering cavity B5 of the second filtering branch 122 is further disposed adjacent to the eighth filtering cavity a8, the seventh filtering cavity a7, and the fifth filtering cavity a5 of the first filtering branch 121, and the fourth filtering cavity B4 and the seventh filtering cavity B7 of the second filtering branch 122, respectively; the second filtering cavity a2 of the first filtering branch 121 is further disposed adjacent to the sixth filtering cavity a6, the fifth filtering cavity a5, the fourth filtering cavity a4, the third filtering cavity A3 and the first filtering cavity a1 of the first filtering branch 121, respectively; the second filter cavity B2 of the second filter branch 122 is further disposed adjacent to the third filter cavity B3 and the first filter cavity B1, respectively, of the second filter branch 122. By such a way of adjacent arrangement, the arrangement between the cavities can be tighter, and the size of the filter 10 can be reduced.

Referring to fig. 2 again, fig. 2 is a schematic diagram of a topology structure of an embodiment of the first filtering branch 121 provided in the present application, and the first filtering cavity a1 to the eighth filtering cavity A8 of the first filtering branch 121 may be pure window coupling, which has good consistency of window coupling and low cost, and no other material (e.g., inductive cross-coupling material) needs to be arranged.

Referring to fig. 3 again, fig. 3 is a schematic diagram of a topology structure of an embodiment of the second filtering branch 122 provided in the present application, and the first filtering chamber B1 to the eighth filtering chamber B8 of the second filtering branch 122 may also be pure window coupling, so that the window consistency is good, the cost is low, and no other material is required to be arranged.

Optionally, the housing 11 is further provided with a first port (not shown), a second port (not shown), a third port (not shown), and a fourth port (not shown), the first filter cavity a1 of the first filter branch 121 is connected to the first port, the eighth filter cavity A8 of the first filter branch 121 is connected to the second port, the first filter cavity B1 of the second filter branch 122 is connected to the third port, and the eighth filter cavity B8 of the second filter branch 122 is connected to the fourth port. The first port, the second port, the third port and the fourth port may be taps of the filter 10.

In a specific embodiment, in the first filtering branch 121, the coupling bandwidth between the first port and the first filtering cavity a1 of the first filtering branch 121 is in the range of 53MHz-63 MHz; the coupling bandwidth between the first filter cavity a1 and the second filter cavity a2 of the first filter branch 121 ranges from 43MHz to 52 MHz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 121 is in the range of 30MHz-38 MHz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 121 is in the range of 28MHz to 35 MHz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 121 is in the range of 28MHz to 35 MHz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 121 ranges from 28MHz to 35 MHz; the coupling bandwidth between the sixth filtering cavity a6 and the seventh filtering cavity a7 of the first filtering branch 121 ranges from 30MHz to 38 MHz; the coupling bandwidth between the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 121 ranges from 43MHz to 52 MHz; the coupling bandwidth between the eighth filter cavity A8 of the first filter branch 121 and the second port is in the range of 53MHz-63 MHz.

The resonant frequencies of the first filter cavity a1 through the eighth filter cavity A8 of the first filter branch 121 are sequentially in the following ranges: 2139MHz-2141MHz, 2139MHz-2141MHz, 2139MHz-2141MHz, 2139MHz-2141MHz, and 2139MHz-2141 MHz.

Therefore, the bandwidth of the first filtering branch 121 of the present embodiment is in the range of 2109MHz-2171MHz, and the bandwidth of the first filtering branch 121 can be accurately controlled, so as to meet the design requirement of the filter 10.

As shown in fig. 4, fig. 4 is a schematic diagram of a simulation result of an embodiment of the first filtering branch 121 provided in the present application. The simulated bandwidth of the first filtering branch 121 in this embodiment is as shown in a frequency band curve 41 in fig. 4, and it can be obtained that the simulated bandwidth of the first filtering branch 121 is within a range from 2109MHz to 2171MHz, and the bandwidth of the first filtering branch 121 can be accurately controlled. The bandwidth suppression of the first filtering branch 121 in the frequency band range of 2025MHz to 2100MHz is greater than 19 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 2180 MHz-2240 MHz is greater than 15 dB; the out-of-band rejection etc. of the first filtering branch 121 can be improved.

The tuning index parameter of the second filtering branch 122 may be the same as the tuning index parameter of the first filtering branch 121, and is not described herein again. The simulation result of the second filtering branch 122 is the same as the frequency band curve 41 shown in fig. 4, and is not described herein again. Therefore, the simulated bandwidth of the second filtering branch 122 may be in the range of 2109MHz-2171MHz, which enables precise control of the bandwidth of the second filtering branch 122.

Further, as shown in fig. 1, the filter 10 of this embodiment may further include a third filtering branch 123 and a fourth filtering branch 124, where the first filtering branch 121, the second filtering branch 122, the third filtering branch 123 and the fourth filtering branch 124 are sequentially disposed along the second direction D. The third filtering branch 123 and the fourth filtering branch 124 may be a transmitting filtering branch or a receiving filtering branch.

The third filtering branch 123 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the third filtering branch 123 are specifically a first filtering cavity C1, a second filtering cavity C2, a third filtering cavity C3, a third filtering cavity C4, a fifth filtering cavity C5, a sixth filtering cavity C6, a seventh filtering cavity C7 and an eighth filtering cavity C8 of the third filtering branch 123. The fourth filtering branch 124 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the fourth filtering branch 124 are specifically a first filtering cavity D1, a second filtering cavity D2, a third filtering cavity D3, a third filtering cavity D4, a fifth filtering cavity D5, a sixth filtering cavity D6, a seventh filtering cavity D7 and an eighth filtering cavity D8 of the fourth filtering branch 124.

As shown in fig. 1, the first through eighth filter cavities C1 through C8 of the third filter branch 123 and the first through eighth filter cavities D1 through D8 of the fourth filter branch 124 are divided into four columns arranged in the second direction D. Specifically, the first filter cavity C1, the second filter cavity C2, the third filter cavity C3 and the eighth filter cavity C8 of the third filter branch 123 are in a row and are sequentially arranged along the first direction L; the second filter cavity D2, the third filter cavity D3 of the fourth filter branch 124, and the fourth filter cavity C4 and the seventh filter cavity C7 of the third filter branch 123 are in a row and are sequentially arranged along the first direction L; the first filter cavity D1, the fourth filter cavity D4 of the fourth filter branch 124, and the fifth filter cavity C5 and the sixth filter cavity C6 of the third filter branch 123 are in a row and are sequentially arranged along the first direction L; the fifth filter cavity D5, the sixth filter cavity D6, the seventh filter cavity D7 and the eighth filter cavity D8 of the fourth filter branch 124 are in a row and are sequentially arranged along the first direction L. Therefore, the eight filter cavities of the third filter branch 123 and the eight filter cavities of the fourth filter branch 124 can be regularly divided into four rows, which facilitates the design of the filter 10 and reduces the size of the filter 10.

The sixth filtering cavity C6 of the third filtering branch 123 is further disposed adjacent to the seventh filtering cavity C7, the fourth filtering cavity C4, the fifth filtering cavity C5 of the third filtering branch 123, and the seventh filtering cavity D7 and the eighth filtering cavity D8 of the fourth filtering branch 124, respectively; the fourth filtering cavity D4 of the fourth filtering branch 124 is further disposed adjacent to the fifth filtering cavity C5 of the third filtering branch 123 and the third filtering cavity D3, the second filtering cavity D2, the first filtering cavity D1, the fifth filtering cavity D5, and the sixth filtering cavity D6 of the fourth filtering branch 124, respectively. By such a way of adjacent arrangement, the cavities can be arranged more closely, and the volume of the filter 10 is reduced.

As shown in fig. 5, fig. 5 is a schematic topology diagram of an embodiment of the third filtering branch 123 provided in the present application, and the first filtering cavity C1 to the eighth filtering cavity C8 of the third filtering branch 123 may be pure window coupling, so that the window coupling has good consistency and low cost, and no other material (e.g., inductive cross-coupling material) is required.

Referring to fig. 6 again, fig. 6 is a schematic diagram of a topology structure of an embodiment of the fourth filtering branch 124 provided in the present application, and the first filtering cavity D1 to the eighth filtering cavity D8 of the fourth filtering branch 124 may also be pure window coupling, so that the window consistency is good, the cost is low, and no other material is required to be arranged.

Optionally, the housing 11 is further provided with a fifth port (not shown), a sixth port (not shown), a seventh port (not shown), and an eighth port (not shown), the first filter cavity C1 of the third filter branch 123 is connected to the fifth port, the eighth filter cavity C8 of the third filter branch 123 is connected to the sixth port, the first filter cavity D1 of the fourth filter branch 124 is connected to the seventh port, and the eighth filter cavity D8 of the fourth filter branch 124 is connected to the eighth port. Wherein the fifth port, the sixth port, the seventh port, and the eighth port may be taps of the filter 10.

The tuning index parameter of the third filtering branch 123 may be the same as the tuning index parameter of the first filtering branch 121, and is not described herein again. The simulation result of the third filtering branch 123 is the same as the frequency band curve 41 shown in fig. 4, and is not described herein again. Therefore, the simulated bandwidth of the third filtering branch 123 may be in the range of 2109MHz-2171MHz, which enables precise control of the bandwidth of the third filtering branch 123.

The tuning indicator parameter of the fourth filtering branch 124 may be the same as the tuning indicator parameter of the first filtering branch 121, and is not described herein again. The simulation result of the fourth filtering branch 124 is the same as the frequency band curve 41 shown in fig. 4, and is not described herein again. Therefore, the simulated bandwidth of the fourth filtering branch 124 is in the range of 2109MHz-2171MHz, and the bandwidth of the fourth filtering branch 124 can be precisely controlled.

In addition, the filter 10 of the present application can also flexibly adjust parameters of the filter cavity to obtain different bandwidths and debugging indexes. In other embodiments, the bandwidth of the first filtering branch 121 may also be in the range of 1835.5MHz-1864 MHz.

Specifically, the coupling bandwidth between the first port and the first filtering cavity a1 of the first filtering branch 121 is in the range of 24MHz-31 MHz; the coupling bandwidth between the first filter cavity a1 and the second filter cavity a2 of the first filter branch 121 is in the range of 19MHz-25 MHz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 121 is in the range of 12MHz-18 MHz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 121 ranges from 11MHz to 17 MHz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 121 ranges from 11MHz to 17 MHz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 121 is in the range of 11MHz-15 MHz; the coupling bandwidth between the sixth filtering cavity a6 and the seventh filtering cavity a7 of the first filtering branch 121 ranges from 12MHz to 18 MHz; the coupling bandwidth between the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 121 ranges from 19MHz to 25 MHz; the coupling bandwidth between the eighth filter cavity A8 of the first filter branch 121 and the second port is in the range of 24MHz-31 MHz.

The resonant frequencies of the first filter cavity a1 through the eighth filter cavity A8 of the first filter branch 121 are sequentially in the following ranges: 1849MHz to 1851MHz, 1849MHz to 1851 MHz.

As shown in fig. 7, fig. 7 is a schematic diagram of a simulation result of another embodiment of the first filtering branch 121 provided in the present application. The simulated bandwidth of the first filtering branch 121 in this embodiment is as shown in the frequency band curve 71 in fig. 7, and it can be obtained that the simulated bandwidth of the first filtering branch 121 is within the range of 1835.5MHz-1864MHz, and the bandwidth of the first filtering branch 121 can be precisely controlled. The bandwidth suppression of the first filtering branch 121 in the frequency band range of 0.009 MHz-1626.5 MHz is greater than 107 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 1626.5 MHz-1661.5 MHz is more than 118 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1661.5 MHz-1743.9 MHz is more than 107 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1743.9 MHz-1766 MHz is greater than 112 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range from 1766MHz to 1786MHz is greater than 82 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 1786MHz to 1796MHz is greater than 31 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 1796MHz to 1825.9MHz is greater than 32 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1883.5 MHz-1886 MHz is greater than 77 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1889 MHz-1899 MHz is greater than 31 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1899MHz to 1919MHz is larger than 61 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1919 MHz-1954 MHz is more than 97 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1954 MHz-1979 MHz is more than 97 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1979MHz to 2024MHz is more than 118 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 2024MHz to 2600MHz is greater than 87 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 2600MHz to 3800MHz is greater than 77 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 3800 MHz-5640 MHz is greater than 42 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 7220MHz to 7520MHz is greater than 32 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 9025MHz to 9400MHz is greater than 32 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 10830 MHz-11280 MHz is greater than 22 dB; the out-of-band rejection etc. of the first filtering branch 121 can be improved.

In this embodiment, the debugging index parameters of the second filtering branch 122, the third filtering branch 123 and the fourth filtering branch 124 may be the same as the debugging index parameters of the first filtering branch 121, and are not described herein again. The simulation results of the second filtering branch 122, the third filtering branch 123 and the fourth filtering branch 124 are the same as the frequency band curve 71 shown in fig. 7, and are not described herein again.

The present application also provides a second embodiment of the filter, which is described on the basis of the filter 10 disclosed in the first embodiment. As shown in fig. 8, fig. 8 is a schematic structural diagram of a second embodiment of the filter provided in the present application, and unlike the first embodiment, in this embodiment, eight filter cavities of the first filter branch 121 may further form three capacitive cross-coupling zeros of the first filter branch 121.

Referring to fig. 8 and 9, fig. 9 is a schematic diagram of a topology of another embodiment of the first filter branch 121 provided by the present application, specifically, a capacitive cross coupling is performed between the second filter cavity a2 and the fourth filter cavity a4 of the first filter branch 121, the second filter cavity a2 and the fifth filter cavity a5 of the first filter branch 121 are capacitively cross coupled, and the fifth filter cavity a5 and the seventh filter cavity a7 of the first filter branch 121 are capacitively cross coupled, so as to form three capacitive cross coupling zeros of the first filter branch 121. Generally, the capacitive coupling zero is realized by a capacitive cross-coupling element, and a typical capacitive cross-coupling element may be a flying bar. That is, for example, a flying bar is disposed between the second filter chamber a2 and the fourth filter chamber a4 of the first filter branch 121. The first filtering branch 121 is only provided with a capacitive cross coupling zero point, and the required materials are the same, so that the material types can be reduced, the complexity of design is reduced, and the stability of the filter 10 is improved.

The cross-coupling zeros are also referred to as transmission zeros. The transmission zero is the transmission function of the filter is equal to zero, namely, the electromagnetic energy cannot pass through the network on the frequency point corresponding to the transmission zero, so that the full isolation effect is achieved, the suppression effect on signals outside the passband is achieved, and the high isolation among the multiple passbands can be better achieved.

Further, the eight filter cavities of the second filter branch 122 form three capacitive cross-coupling zeros of the second filter branch 122. Referring to fig. 8 and 10, fig. 10 is a schematic diagram of a topology structure of another embodiment of the second filtering branch 122 provided in the present application, in which a second filtering cavity B2 and a fourth filtering cavity B4 of the second filtering branch 122 are capacitively cross-coupled, a fourth filtering cavity B4 and a seventh filtering cavity B7 of the second filtering branch 122 are capacitively cross-coupled, and a fifth filtering cavity B5 and a seventh filtering cavity B7 of the second filtering branch 122 are capacitively cross-coupled to form three capacitively cross-coupled zeros of the second filtering branch 122, so as to implement zero suppression and facilitate tuning of indexes. The second filtering branch 122 is only provided with a capacitive cross coupling zero point, the required materials are the same, the material types can be reduced, the design complexity is reduced, and the stability of the filter 10 is improved.

Eight filter cavities of the third filter branch 123 form three cross-coupling zeros of the third filter branch 123, as shown in fig. 11, fig. 11 is a schematic diagram of a topology structure of another embodiment of the third filter branch 123 provided in the present application, a second filter cavity C2 of the third filter branch 123 is capacitively cross-coupled with a fourth filter cavity C4, a fourth filter cavity C4 of the third filter branch 123 is capacitively cross-coupled with a sixth filter cavity C6, and a fourth filter cavity C4 of the third filter branch 123 is capacitively cross-coupled with a seventh filter cavity C7, so as to form the three capacitive cross-coupling zeros of the third filter branch 123, which can implement zero suppression and facilitate debugging of indexes. The third filtering branch 123 is only provided with a capacitive cross coupling zero point, the required materials are the same, the material types are reduced, the complexity of design can be reduced, and the stability of the filter 10 is improved.

Eight filter cavities of the fourth filter branch 124 form three cross-coupling zeros of the fourth filter branch 123, as shown in fig. 12, fig. 12 is a schematic diagram of a topology structure of another embodiment of the fourth filter branch 124 provided in the present application, a capacitive cross-coupling exists between the first filter cavity D1 and the fourth filter cavity D4 of the fourth filter branch 124, a capacitive cross-coupling exists between the second filter cavity D2 and the fourth filter cavity D4 of the fourth filter branch 124, and a capacitive cross-coupling exists between the fourth filter cavity D4 and the sixth filter cavity D6 of the fourth filter branch 124, so as to form the three capacitive cross-coupling zeros of the fourth filter branch 124, which can implement zero suppression and facilitate debugging of indexes. The fourth filtering branch 124 is only provided with a capacitive cross coupling zero point, the required materials are the same, the material types are reduced, the complexity of design can be reduced, and the stability of the filter 10 is improved.

In this embodiment, in the first filtering branch 121, the coupling bandwidth between the first port and the first filtering cavity a1 of the first filtering branch 121 is in the range of 26MHz to 34 MHz; the coupling bandwidth between the first filter cavity a1 and the second filter cavity a2 of the first filter branch 121 is in the range of 21MHz-28 MHz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 121 is in the range of 14MHz-20 MHz; the coupling bandwidth between the second filter cavity a2 and the fourth filter cavity a4 of the first filter branch 121 ranges from (-5) MHz to 0 MHz; the coupling bandwidth between the second filter cavity a2 and the fifth filter cavity a5 of the first filter branch 121 ranges from (-3) MHz to 1 MHz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 121 is in the range of 14MHz-20 MHz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 121 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 121 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fifth filtering cavity a5 and the seventh filtering cavity a7 of the first filtering branch 121 is in the range of (-6) MHz- (-1) MHz; the coupling bandwidth between the sixth filtering cavity a6 and the seventh filtering cavity a7 of the first filtering branch 121 ranges from 14MHz to 20 MHz; the coupling bandwidth between the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 121 ranges from 21MHz to 28 MHz; the coupling bandwidth between the eighth filter cavity A8 of the first filter branch 121 and the second port is in the range of 26MHz-34 MHz.

The resonant frequencies of the first filter cavity a1 through the eighth filter cavity A8 of the first filter branch 121 are sequentially in the following ranges: 1816MHz to 1818MHz, 1813MHz to 1815MHz, 1816MHz to 1818MHz, 1812MHz to 1814MHz, 1816MHz to 1818 MHz.

Therefore, the bandwidth of the first filtering branch 121 of the present embodiment is located in the range of 1804-1831MHz, and the bandwidth of the first filtering branch 121 can be accurately controlled, so as to meet the design requirement of the filter 10.

As shown in fig. 13, fig. 13 is a schematic diagram of a simulation result of another embodiment of the first filtering branch 121 provided in the present application. The simulated bandwidth of the first filtering branch 121 in this embodiment is as shown in the frequency band curve 103 in fig. 13, and it can be obtained that the simulated bandwidth of the first filtering branch 121 is located in a range from 1804MHz to 1831MHz, and the bandwidth of the first filtering branch 121 can be accurately controlled. The bandwidth suppression of the first filtering branch 121 in the frequency band range of 1710MHz-1735MHz is greater than 113 dB; the bandwidth inhibition of the first filtering branch 121 in the frequency band range of 1735MHz-1770MHz is more than 105 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1770MHz-1785MHz is greater than 86 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1785MHz-1795MHz is greater than 25 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1795MHz to 1800MHz is greater than 3 dB; the bandwidth suppression of the first filtering branch 121 in the frequency band range of 1880MHz-1910MHz is greater than 81 dB; the out-of-band rejection etc. of the first filtering branch 121 can be improved.

In the second filtering branch 122, the coupling bandwidth between the third port and the first filtering cavity B1 of the second filtering branch 122 is in the range of 26MHz-34 MHz; the coupling bandwidth between the first filter cavity B1 and the second filter cavity B2 of the second filter branch 122 is in the range of 21MHz-28 MHz; the coupling bandwidth between the second filter cavity B2 and the third filter cavity B3 of the second filter branch 122 is in the range of 14MHz-20 MHz; the coupling bandwidth between the second filter cavity B2 and the fourth filter cavity B4 of the second filter branch 122 is in the range of (-8) MHz- (-3) MHz; the coupling bandwidth between the third filter cavity B3 and the fourth filter cavity B4 of the second filter branch 122 is in the range of 13MHz-18 MHz; the coupling bandwidth between the fourth filter cavity B4 and the fifth filter cavity B5 of the second filter branch 122 ranges from 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity B4 and the seventh filter cavity B7 of the second filter branch 122 ranges from (-3) MHz to 1 MHz; the coupling bandwidth between the fifth filter cavity B5 and the sixth filter cavity B6 of the second filter branch 122 is in the range of 14MHz-20 MHz; the coupling bandwidth between the fifth filter cavity B5 and the seventh filter cavity B7 of the second filter branch 122 ranges from (-2) MHz to 2 MHz; the coupling bandwidth between the sixth filtering cavity B6 and the seventh filtering cavity B7 of the second filtering branch 122 is in the range of 15MHz-20 MHz; the coupling bandwidth between the seventh filtering cavity B7 and the eighth filtering cavity B8 of the second filtering branch 122 is in the range of 21MHz-28 MHz; the coupling bandwidth between the eighth filter cavity B8 and the fourth port of the second filter branch 122 is in the range of 26MHz-34 MHz.

The resonant frequencies of the first filter cavity B1 through the eighth filter cavity B8 of the second filter branch 122 are sequentially in the following ranges: 1816MHz to 1818MHz, 1810MHz to 1812MHz, 1816MHz to 1818MHz, 1815MHz to 1817MHz, 1816MHz to 1818 MHz.

The simulation result of the second filtering branch 122 is the same as the frequency band curve 103 shown in fig. 13, and is not described herein again, and the bandwidth of the second filtering branch 122 simulation can be obtained within a range from 1804MHz to 1831MHz, which meets the design requirement of the filter 10, and can accurately control the bandwidth of the second filtering branch 122.

In the third filtering branch 123, the coupling bandwidth between the fifth port and the first filtering cavity C1 of the third filtering branch 123 is in the range of 26MHz-34 MHz; the coupling bandwidth between the first filter cavity C1 and the second filter cavity C2 of the third filter branch 123 ranges from 21MHz to 28 MHz; the coupling bandwidth between the second filter cavity C2 and the third filter cavity C3 of the third filter branch 123 is in the range of 14MHz-20 MHz; the coupling bandwidth between the second filter cavity C2 and the fourth filter cavity C4 of the third filter branch 123 is in the range of (-8) MHz- (-3) MHz; the coupling bandwidth between the third filter cavity C3 and the fourth filter cavity C4 of the third filter branch 123 is in the range of 13MHz-18 MHz; the coupling bandwidth between the fourth filter cavity C4 and the fifth filter cavity C5 of the third filter branch 123 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity C4 and the sixth filter cavity C6 of the third filter branch 123 ranges from (-2) MHz to 2 MHz; the coupling bandwidth between the fourth filtering cavity C4 and the seventh filtering cavity C7 of the third filtering branch 123 ranges from (-3) MHz to 1 MHz; the coupling bandwidth between the fifth filter cavity C5 and the sixth filter cavity C6 of the third filter branch 123 is in the range of 14MHz-20 MHz; the coupling bandwidth between the sixth filtering cavity C6 and the seventh filtering cavity C7 of the third filtering branch 123 ranges from 15MHz to 20 MHz; the coupling bandwidth between the seventh filtering cavity C7 and the eighth filtering cavity C8 of the third filtering branch 123 ranges from 21MHz to 28 MHz; the coupling bandwidth between the eighth filter cavity C8 of the third filter branch 123 and the sixth port is in the range of 26MHz-34 MHz.

The resonant frequencies of the first filter cavity C1 through the eighth filter cavity C8 of the third filter branch 123 are sequentially in the following ranges:

1816MHz-1818MHz，1816MHz-1818MHz，1810MHz-1812MHz，1816MHz-1818MHz，1815MHz-1817MHz，1816MHz-1818MHz，1816MHz-1818MHz，1816MHz-1818MHz。

the simulation result of the third filtering branch 123 is the same as the frequency band curve 103 shown in fig. 13, and is not described herein again, and the bandwidth of the third filtering branch 123 simulation can be obtained within a range from 1804MHz to 1831MHz, which meets the design requirement of the filter 10, and the bandwidth of the third filtering branch 123 can be accurately controlled.

In the fourth filtering branch 124, the coupling bandwidth between the seventh port and the first filtering cavity D1 of the fourth filtering branch 124 is in the range of 26MHz-34 MHz; the coupling bandwidth between the first filter cavity D1 and the second filter cavity D2 of the fourth filter branch 124 is in the range of 21MHz-28 MHz; the coupling bandwidth between the first filter cavity D1 and the fourth filter cavity D4 of the fourth filter branch 124 is in the range of (-3) MHz-1 MHz; the coupling bandwidth between the second filter cavity D2 and the third filter cavity D3 of the fourth filter branch 124 is in the range of 15MHz-21 MHz; the coupling bandwidth between the second filter cavity D2 and the fourth filter cavity D4 of the fourth filter branch 124 is in the range of (-5) MHz- (-1) MHz; the coupling bandwidth between the third filter cavity D3 and the fourth filter cavity D4 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the fourth filter cavity D4 and the fifth filter cavity D5 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the fourth filtering cavity D4 and the sixth filtering cavity D6 of the fourth filtering branch 124 is in the range of (-5) MHz- (-1) MHz; the coupling bandwidth between the fifth filter cavity D5 and the sixth filter cavity D6 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the sixth filtering cavity D6 and the seventh filtering cavity D7 of the fourth filtering branch 124 is in the range of 15MHz-20 MHz; the coupling bandwidth between the seventh filtering cavity D7 and the eighth filtering cavity D8 of the fourth filtering branch 124 is in the range of 21MHz-28 MHz; the coupling bandwidth between the eighth filter cavity D8 and the eighth port of the fourth filter branch 124 is in the range of 26MHz-34 MHz.

The resonant frequencies of the first filter cavity D1 through the eighth filter cavity D8 of the fourth filter branch 124 are sequentially in the following ranges:

1816MHz-1818MHz，1816MHz-1818MHz，1813MHz-1815MHz，1816MHz-1818MHz，1812MHz-1814MHz，1816MHz-1818MHz，1816MHz-1818MHz，1816MHz-1818MHz。

the simulation result of the fourth filtering branch 124 is the same as the frequency band curve 103 shown in fig. 13, and details are not repeated here, and the bandwidth of the fourth filtering branch 124 simulation can be obtained within a range from 1804MHz to 1831MHz, which meets the design requirement of the filter 10, and can accurately control the bandwidth of the fourth filtering branch 124.

In addition, the filter 10 of the present application can also flexibly adjust parameters of the filter cavity to obtain different bandwidths and debugging indexes. In other embodiments, the bandwidth of the first filtering branch 121 may also be in the range of 1801MHz-1832 MHz.

Specifically, in the first filtering branch 121, the coupling bandwidth between the first filtering cavity a1 and the second filtering cavity a2 of the first filtering branch 121 is in the range of 22MHz-29 MHz; the coupling bandwidth between the second filter cavity a2 and the third filter cavity A3 of the first filter branch 121 is in the range of 15MHz-21 MHz; the coupling bandwidth between the second filter cavity a2 and the fourth filter cavity a4 of the first filter branch 121 ranges from 0MHz to 5 MHz; the coupling bandwidth between the second filter cavity a2 and the fifth filter cavity a5 of the first filter branch 121 ranges from (-4) MHz to 0 MHz; the coupling bandwidth between the third filter cavity A3 and the fourth filter cavity a4 of the first filter branch 121 is in the range of 16MHz-22 MHz; the coupling bandwidth between the fourth filter cavity a4 and the fifth filter cavity a5 of the first filter branch 121 is in the range of 13MHz-20 MHz; the coupling bandwidth between the fifth filter cavity a5 and the sixth filter cavity a6 of the first filter branch 121 is in the range of 13MHz-20 MHz; the coupling bandwidth between the fifth filtering cavity a5 and the seventh filtering cavity a7 of the first filtering branch 121 is in the range of (-5) MHz- (-1) MHz; the coupling bandwidth between the sixth filtering cavity a6 and the seventh filtering cavity a7 of the first filtering branch 121 ranges from 15MHz to 21 MHz; the coupling bandwidth between the seventh filtering cavity a7 and the eighth filtering cavity A8 of the first filtering branch 121 ranges from 23MHz to 29 MHz; the coupling bandwidth between the eighth filter cavity A8 of the first filter branch 121 and the second port is in the range of 29MHz-37 MHz.

The resonant frequencies of the first filter cavity a1 through the eighth filter cavity A8 of the first filter branch 121 are sequentially in the following ranges: 1822MHz-1824MHz, 1818MHz-1820MHz, 1820MHz-1822MHz, 1818MHz-1820MHz, 1818MHz-1820MHz, 1814MHz-1816MHz, 1818MHz-1820MHz, 1818MHz-1820 MHz.

Therefore, the bandwidth of the first filtering branch 121 of this embodiment is within a range from 1801MHz to 1832MHz, so that the bandwidth of the first filtering branch 121 can be accurately controlled, and the design requirement of the filter 10 is met.

As shown in fig. 14, fig. 14 is a schematic diagram of a simulation result of a further embodiment of the first filtering branch 121 provided in the present application. The simulated bandwidth of the first filtering branch 121 in this embodiment is as shown in the frequency band curve 104 in fig. 14, and it can be obtained that the simulated bandwidth of the first filtering branch 121 is within a range from 1801MHz to 1832MHz, and the bandwidth of the first filtering branch 121 can be precisely controlled. When the frequency of the first filtering branch 121 is 1805MHz, the suppression is greater than 1 dB; when the frequency of the first filtering branch 121 is 1830MHz, the rejection is greater than 1 dB; when the frequency of the first filtering branch 121 is 1770MHz, the rejection is greater than 116 dB; when the frequency of the first filtering branch 121 is 1785MHz, the rejection is greater than 94 dB; when the frequency of the first filtering branch 121 is 1795MHz, the rejection is greater than 40 dB; when the frequency of the first filtering branch 121 is 1800MHz, the rejection is greater than 4 dB; the first filtering branch 121 suppresses more than 92dB at a frequency of 1880 MHz; the out-of-band rejection etc. of the first filtering branch 121 can be improved.

In the second filter branch 122, the coupling bandwidth between the first filter cavity B1 and the second filter cavity B2 of the second filter branch 122 is in the range of 22MHz-29 MHz; the coupling bandwidth between the second filter cavity B2 and the third filter cavity B3 of the second filter branch 122 is in the range of 19MHz to 21 MHz; the coupling bandwidth between the second filter cavity B2 and the fourth filter cavity B4 of the second filter branch 122 is in the range of (-7) MHz- (-7) MHz; the coupling bandwidth between the third filter cavity B3 and the fourth filter cavity B4 of the second filter branch 122 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity B4 and the fifth filter cavity B5 of the second filter branch 122 ranges from 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity B4 and the seventh filter cavity B7 of the second filter branch 122 ranges from (-3) MHz to 1 MHz; the coupling bandwidth between the fifth filter cavity B5 and the sixth filter cavity B6 of the second filter branch 122 ranges from 15MHz to 21 MHz; the coupling bandwidth between the fifth filter cavity B5 and the seventh filter cavity B7 of the second filter branch 122 ranges from 2MHz to 6 MHz; the coupling bandwidth between the sixth filtering cavity B6 and the seventh filtering cavity B7 of the second filtering branch 122 ranges from 15MHz to 21 MHz; the coupling bandwidth between the seventh filtering cavity B7 and the eighth filtering cavity B8 of the second filtering branch 122 is in the range of 22MHz-29 MHz; the coupling bandwidth between the eighth filter cavity B8 and the fourth port of the second filter branch 122 is in the range of 29MHz-37 MHz.

The resonant frequencies of the first filter cavity B1 through the eighth filter cavity B8 of the second filter branch 122 are sequentially in the following ranges: 1822MHz-1824MHz, 1818MHz-1820MHz, 1812MHz-1814MHz, 1818MHz-1820MHz, 1818MHz-1820MHz, 1823MHz-1825MHz, 1818MHz-1820MHz, 1818MHz-1820 MHz.

In this embodiment, the simulation result of the second filtering branch 122 is the same as the frequency band curve 104 in fig. 14, and is not repeated here. The simulated bandwidth of the second filtering branch 122 is in the range of 1801MHz-1832MHz, which can accurately control the bandwidth of the second filtering branch 122.

In the third filtering branch 123, the coupling bandwidth between the first filtering cavity C1 and the second filtering cavity C2 of the third filtering branch 123 is in the range of 22MHz-29 MHz; the coupling bandwidth between the second filter cavity C2 and the third filter cavity C3 of the third filter branch 123 is in the range of 15MHz-21 MHz; the coupling bandwidth between the second filter cavity C2 and the fourth filter cavity C4 of the third filter branch 123 is in the range of (-8) MHz- (-3) MHz; the coupling bandwidth between the third filter cavity C3 and the fourth filter cavity C4 of the third filter branch 123 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity C4 and the fifth filter cavity C5 of the third filter branch 123 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity C4 and the sixth filter cavity C6 of the third filter branch 123 is in the range of 2MHz to 6 MHz; the coupling bandwidth between the fourth filtering cavity C4 and the seventh filtering cavity C7 of the third filtering branch 123 ranges from (-4) MHz to 1 MHz; the coupling bandwidth between the fifth filter cavity C5 and the sixth filter cavity C6 of the third filter branch 123 is in the range of 15MHz-21 MHz; the coupling bandwidth between the sixth filtering cavity C6 and the seventh filtering cavity C7 of the third filtering branch 123 ranges from 14MHz to 22 MHz; the coupling bandwidth between the seventh filtering cavity C7 and the eighth filtering cavity C8 of the third filtering branch 123 ranges from 23MHz to 30 MHz; the coupling bandwidth between the eighth filter cavity C8 of the third filter branch 123 and the sixth port is in the range of 30MHz-36 MHz.

1822MHz-1824MHz，1818MHz-1820MHz，1812MHz-1814MHz，1818MHz-1820MHz，1823MHz-1825MHz，1818MHz-1820MHz，1818MHz-1820MHz，1818MHz-1820MHz。

in this embodiment, the simulation result of the third filtering branch 123 is the same as the frequency band curve 104 in fig. 14, and is not repeated here. The simulated bandwidth of the third filtering branch 123 is within the range of 1801MHz-1832MHz, which can accurately control the bandwidth of the third filtering branch 123.

In the fourth filtering branch 124, the coupling bandwidth between the first filtering cavity D1 and the second filtering cavity D2 of the fourth filtering branch 124 is in the range of 22MHz-29 MHz; the coupling bandwidth between the first filtering cavity D1 and the fourth filtering cavity D4 of the fourth filtering branch 124 is in the range of (-5) MHz- (-1) MHz; the coupling bandwidth between the second filter cavity D2 and the third filter cavity D3 of the fourth filter branch 124 is in the range of 17MHz-23 MHz; the coupling bandwidth between the second filter cavity D2 and the fourth filter cavity D4 of the fourth filter branch 124 is in the range of (0) MHz- (5) MHz; the coupling bandwidth between the third filter cavity D3 and the fourth filter cavity D4 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the fourth filter cavity D4 and the fifth filter cavity D5 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the fourth filtering cavity D4 and the sixth filtering cavity D6 of the fourth filtering branch 124 is in the range of (-5) MHz- (-1) MHz; the coupling bandwidth between the fifth filter cavity D5 and the sixth filter cavity D6 of the fourth filter branch 124 is in the range of 13MHz-19 MHz; the coupling bandwidth between the sixth filtering cavity D6 and the seventh filtering cavity D7 of the fourth filtering branch 124 is in the range of 15MHz-22 MHz; the coupling bandwidth between the seventh filtering cavity D7 and the eighth filtering cavity D8 of the fourth filtering branch 124 is in the range of 23MHz-30 MHz; the coupling bandwidth between the eighth filter cavity D8 and the eighth port of the fourth filter branch 124 is in the range of 30MHz-36 MHz.

1822MHz-1824MHz，1819MHz-1821MHz，1820MHz-1822MHz，1819MHz-1821MHz，1815MHz-1817MHz，1818MHz-1820MHz，1818MHz-1820MHz，1818MHz-1820MHz。

in this embodiment, the simulation result of the fourth filtering branch 124 is the same as the frequency band curve 104 in fig. 14, and is not repeated here. The simulated bandwidth of the fourth filtering branch 124 is in the range of 1801MHz-1832MHz, which can accurately control the bandwidth of the fourth filtering branch 124.

The present application also provides a third embodiment of the filter, which is described on the basis of the filter 10 disclosed in the second embodiment. Referring to fig. 15, fig. 15 is a schematic structural diagram of a third embodiment of a filter according to the present application. The filter 10 may further comprise a fifth filtering branch 125 and a sixth filtering branch 126. The fifth filtering branch 125 and the sixth filtering branch 126 may be a transmitting filtering branch or a receiving filtering branch.

The fifth filtering branch 125 is composed of eight sequentially coupled filtering cavities, the sixth filtering branch 126 is composed of eight sequentially coupled filtering cavities, and the fifth filtering branch 125 and the sixth filtering branch 126 are adjacently disposed along the second direction D, have the same structure, and are disposed at an interval with the first filtering branch 121 and the second filtering branch 125 along the first direction L.

The eight filter cavities of the fifth filter branch 125 are specifically a first filter cavity E1, a second filter cavity E2, a third filter cavity E3, a fourth filter cavity E4, a fifth filter cavity E5, a sixth filter cavity E6, a seventh filter cavity E7 and an eighth filter cavity E8 of the fifth filter branch 125. The eight filter cavities of the sixth filter branch are specifically 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 of the sixth filter branch 126.

The first filtering cavity E1 to the eighth filtering cavity E8 of the fifth filtering branch 125 are divided into two columns arranged along the second direction D, specifically, the first filtering cavity E1, the second filtering cavity E2, the third filtering cavity E3 and the fourth filtering cavity E4 of the fifth filtering branch 125 are one column and are sequentially arranged along the first direction L; the eighth filter cavity E8, the seventh filter cavity E7, the sixth filter cavity E6 and the fifth filter cavity E5 of the fifth filter branch 125 are in a row and are sequentially arranged along the first direction L. The cavities of the fifth filtering branch 125 are regularly arranged, so that the cavity space can be fully utilized, the miniaturization of the filter 10 is facilitated, and the layout and debugging are facilitated.

The structure of the sixth filtering branch 126 is the same as that of the fifth filtering branch, and is not described herein again. The sixth filtering branch 126 is regularly arranged in cavities, so that the cavity space can be fully utilized, the miniaturization of the filter 10 is facilitated, and the layout and debugging are facilitated.

The seventh filtering cavity E7 of the fifth filtering branch 125 is further disposed adjacent to the eighth filtering cavity E8, the first filtering cavity E1, the second filtering cavity E2, the sixth filtering cavity E6 of the fifth filtering branch 125, and the eighth filtering cavity F8 and the seventh filtering cavity F7 of the sixth filtering branch 126, respectively; the fifth filter cavity E5 of the fifth filter branch 125 is further disposed adjacent to the sixth filter cavity E6, the third filter cavity E3, the fourth filter cavity E4 of the fifth filter branch 125, and the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 126, respectively. Through the adjacent arrangement, the cavities can be arranged more closely, and the size of the filter 10 is reduced.

As shown in fig. 16, fig. 16 is a schematic topology diagram of an embodiment of the fifth filtering branch 125 provided in the present application. The first filter cavity E1 to the eighth filter cavity E8 of the fifth filter branch 125 may be pure window coupling, and the window coupling has good consistency and low cost, and no other material (e.g., inductive cross-coupling material) needs to be provided.

As shown in fig. 17, fig. 17 is a schematic topology diagram of an embodiment of the sixth filtering branch 126 provided in the present application. The first filter cavity F1 to the eighth filter cavity F8 of the sixth filter branch 126 may be pure window coupling, and the window coupling has good consistency and low cost, and no other material (e.g., inductive cross-coupling material) is required.

The housing 11 is further provided with a ninth port (not shown), a tenth port (not shown), an eleventh port (not shown), and a twelfth port (not shown), the first filter cavity E1 of the fifth filter branch 125 is connected to the ninth port, the eighth filter cavity E8 of the fifth filter branch 125 is connected to the tenth port, the first filter cavity F1 of the sixth filter branch 126 is connected to the eleventh port, and the eighth filter cavity D8 of the sixth filter branch 126 is connected to the twelfth port. Wherein the ninth port, the tenth port, the eleventh port, and the twelfth port may be taps of the filter 10.

In the fifth filtering branch 121, the coupling bandwidth between the ninth port and the first filtering cavity E1 of the fifth filtering branch ranges from 53MHz to 63 MHz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch is in the range of 43MHz-52 MHz; the coupling bandwidth range between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch circuit is 30MHz-38 MHz; the coupling bandwidth range between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch circuit is 28MHz-35 MHz; the coupling bandwidth range between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch circuit is 28MHz-35 MHz; the coupling bandwidth range between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch circuit is 28MHz-35 MHz; the coupling bandwidth range between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch circuit is 30MHz-38 MHz; the coupling bandwidth between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch is in the range of 43MHz-52 MHz; the coupling bandwidth between the eighth filter cavity E8 and the tenth port of the fifth filter branch is in the range of 53MHz-63 MHz.

The resonant frequencies of the first filter cavity E1 to the eighth filter cavity E8 of the fifth filter branch 125 are sequentially in the following ranges:

1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz，1949MHz-1951MHz。

as shown in fig. 18, fig. 18 is a schematic diagram of simulation results of an embodiment of the fifth filtering branch 125 provided in the present application. The simulated bandwidth of the fifth filtering branch 125 in this embodiment is as the frequency band curve 108 in fig. 18, and it can be obtained that the simulated bandwidth of the fifth filtering branch 125 is within the range of 1919MHz-1981MHz, and the bandwidth of the fifth filtering branch 125 can be precisely controlled. The bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1910MHz to 1915MHz is greater than 20 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 2000MHz to 2010MHz is more than 25 dB; therefore, the out-of-band rejection performance of the fifth filtering branch 125 can be improved.

In this embodiment, the debugging index parameter of the sixth filtering branch 126 may be the same as the debugging index parameter of the fifth filtering branch 125, and the simulation result of the sixth filtering branch 126 in this embodiment is the same as the frequency band curve 108 in fig. 18, which is not described herein again. The simulated bandwidth of the sixth filtering branch 126 is in the range of 1919MHz-1981MHz, and the bandwidth of the sixth filtering branch 126 can be precisely controlled.

Further, as shown in fig. 15, the filter cavity 10 may further include a seventh filtering branch 127 and an eighth filtering branch 128, the seventh filtering branch 127 and the eighth filtering branch 128 are sequentially arranged along the second direction D and have the same structure, the seventh filtering branch 127 and the sixth filtering branch 126 are symmetrically disposed along the second direction D, and the eighth filtering branch 128 and the fifth filtering branch 125 are symmetrically disposed along the second direction D. The seventh filtering branch 127 and the eighth filtering branch 128 may be transmitting filtering branches or receiving filtering branches.

The eighth filtering branch 128 and the seventh filtering branch 127 are disposed adjacent to each other along the second direction D, have the same structure, and are disposed at an interval with the third filtering branch 123 and the fourth filtering branch 124 along the first direction L.

The seventh filtering branch 127 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the seventh filtering branch 127 are specifically a first filtering cavity G1, a second filtering cavity G2, a third filtering cavity G3, a fourth filtering cavity G4, a fifth filtering cavity G5, a sixth filtering cavity G6, a seventh filtering cavity G7 and an eighth filtering cavity G8 of the seventh filtering branch 127. The eighth filtering branch 128 is composed of eight filtering cavities coupled in sequence, and the eight filtering cavities of the eighth filtering branch 128 are specifically a first filtering cavity H1, a second filtering cavity H2, a third filtering cavity H3, a fourth filtering cavity H4, a fifth filtering cavity H5, a sixth filtering cavity H6, a seventh filtering cavity H7 and an eighth filtering cavity H8 of the eighth filtering branch 128.

The first filtering cavity G1 to the eighth filtering cavity G8 of the seventh filtering branch 127 are divided into two columns arranged along the second direction D, specifically, the first filtering cavity G1, the second filtering cavity G2, the third filtering cavity G3 and the fourth filtering cavity G4 of the seventh filtering branch 127 are one column and are sequentially arranged along the first direction L; the eighth filtering cavity G8, the seventh filtering cavity G7, the sixth filtering cavity G6 and the fifth filtering cavity G5 of the seventh filtering branch 127 are in a row and are sequentially arranged along the first direction L. The seventh filtering branch 127 is regularly arranged in cavities, so that the cavity space can be fully utilized, the miniaturization of the filter is facilitated, and the layout and debugging are facilitated.

The structure of the eighth filtering branch 128 is the same as that of the seventh filtering branch 127, and is not described herein again.

The seventh filtering cavity H7 of the eighth filtering branch 128 is further disposed adjacent to the eighth filtering cavity H8, the first filtering cavity H1, the second filtering cavity H2, the sixth filtering cavity H6 of the eighth filtering branch 128, and the eighth filtering cavity G8 and the seventh filtering cavity G7 of the seventh filtering branch 127, respectively; the fifth filter cavity H5 of the eighth filter branch 128 is further disposed adjacent to the sixth filter cavity H6, the third filter cavity H3, the fourth filter cavity H4 of the eighth filter branch 128, and the fifth filter cavity G5 and the sixth filter cavity G6 of the seventh filter branch 127, respectively. Through the adjacent arrangement, the cavities can be arranged more closely, and the size of the filter 10 is reduced.

As shown in fig. 19, fig. 19 is a schematic topology diagram of an embodiment of the seventh filtering branch 127 provided in the present application. The first filtering cavity G1 to the eighth filtering cavity G8 of the seventh filtering branch 127 may be pure window coupling, and the window coupling has good consistency and low cost, and no other material (e.g., inductive cross-coupling material) needs to be arranged.

As shown in fig. 20, fig. 20 is a schematic topology diagram of an embodiment of the eighth filtering branch 128 provided in the present application. The first filtering cavity H1 to the eighth filtering cavity H8 of the eighth filtering branch 128 may be pure window coupling, which has good consistency of window coupling and low cost, and no other material (e.g., inductive cross-coupling material) is required.

The housing 11 is further provided with a thirteenth port (not shown), a fourteenth port (not shown), a fifteenth port (not shown) and a sixteenth port (not shown), the first filter cavity G1 of the seventh filter branch 127 is connected to the thirteenth port, the eighth filter cavity G8 of the seventh filter branch 127 is connected to the fourteenth port, the first filter cavity H1 of the eighth filter branch 128 is connected to the fifteenth port, and the eighth filter cavity H8 of the eighth filter branch 128 is connected to the sixteenth port. Wherein the thirteenth port, the fourteenth port, the fifteenth port, and the sixteenth port may all be taps of the filter 10.

In this embodiment, the debugging index parameter of the seventh filtering branch 127 may be the same as the debugging index parameter of the fifth filtering branch 125, and is not described herein again. The simulation result of the seventh filtering branch 127 of this embodiment is the same as the frequency band curve 108 in fig. 18, and is not described herein again. The simulated bandwidth of the seventh filtering branch 127 is in the range of 1919MHz-1981MHz, and the bandwidth of the seventh filtering branch 127 can be precisely controlled.

In this embodiment, the index parameter of the eighth filtering branch 128 may be the same as the index parameter of the fifth filtering branch 125, and is not described herein again. The bandwidth of the eighth filtering branch 128 of this embodiment is simulated as the frequency band curve 108 in fig. 18, and is not described herein again. The simulated bandwidth of the eighth filtering branch 128 is in the range of 1919MHz-1981MHz, and the bandwidth of the eighth filtering branch 128 can be precisely controlled.

In addition, the filter 10 of the present embodiment can also flexibly adjust parameters of the filter cavity to obtain different bandwidths and tuning indexes. In other embodiments, the bandwidth of the fifth filtering branch 125 may also be in the range of 1741.9MHz-1767.5 MHz.

Specifically, in the fifth filtering branch 121, the coupling bandwidth between the ninth port and the first filtering cavity E1 of the fifth filtering branch ranges from 21MHz to 28 MHz; the coupling bandwidth range between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch circuit is 17MHz-23 MHz; the coupling bandwidth range between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch circuit is 11MHz-16 MHz; the coupling bandwidth range between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch circuit is 10MHz-15 MHz; the coupling bandwidth range between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch circuit is 10MHz-15 MHz; the coupling bandwidth range between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch circuit is 10MHz-15 MHz; the coupling bandwidth range between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch circuit is 11MHz-16 MHz; the coupling bandwidth range between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch circuit is 17MHz-23 MHz; the coupling bandwidth between the eighth filter cavity E8 and the tenth port of the fifth filter branch is in the range of 21MHz-28 MHz.

1754MHz-1756MHz，1754MHz-1756MHz，1754MHz-1756MHz，1754MHz-1756MHz，1754MHz-1756MHz，1754MHz-1756MHzz，1754MHz-1756MHz，1754MHz-1756MHz。

as shown in fig. 21, fig. 21 is a schematic diagram of a simulation result of another embodiment of the fifth filtering branch 125 provided in the present application. The simulated bandwidth of the fifth filtering branch 125 in this embodiment is as the frequency band curve 201 in fig. 21, and it can be obtained that the simulated bandwidth of the fifth filtering branch 125 is within the range of 1741.9MHz-1767.5MHz, and the bandwidth of the fifth filtering branch 125 can be precisely controlled. The bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 0.009 MHz-1500 MHz is greater than 81 dB; the bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1616 MHz-1666 MHz is greater than 81 dB; the bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1666 MHz-1685 MHz is greater than 46 dB; the bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1685 MHz-1730.9 MHz is greater than 26 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 1803.9 MHz-1838.9 MHz is larger than 61 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 1838.9 MHz-1878.9 MHz is greater than 86 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 1878.9 MHz-3600 MHz is greater than 81 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 3600 MHz-5000 MHz is greater than 41 dB; therefore, the out-of-band rejection performance of the fifth filtering branch 125 can be improved.

In this embodiment, the debugging index parameters of the sixth filtering branch 126, the seventh filtering branch 127 and the eighth filtering branch 128 may be the same as the debugging index parameters of the fifth filtering branch 125, and are not described herein again. The simulation results of the sixth filtering branch 126, the seventh filtering branch 127 and the eighth filtering branch 128 are the same as the frequency band curve 201 in fig. 21, and are not described herein again.

The present application also provides a fourth embodiment of the filter, which is described on the basis of the filter 10 disclosed in the third embodiment. As shown in fig. 22, fig. 22 is a schematic structural diagram of a fourth embodiment of the filter 10 provided in the present application, and is different from the third embodiment in that eight filter cavities of the fifth filter branch 125 form four cross-coupling zeros of the fifth filter branch 125 in the present embodiment.

As shown in fig. 23, fig. 23 is a schematic topology diagram of another embodiment of the fifth filtering branch 125 provided by the present application, specifically, a capacitive cross coupling exists between the second filtering cavity E2 and the seventh filtering cavity E7 of the fifth filtering branch 125, a capacitive cross coupling exists between the second filtering cavity E2 and the sixth filtering cavity E6 of the fifth filtering branch 125, an inductive cross coupling exists between the third filtering cavity E3 and the fifth filtering cavity E5 of the fifth filtering branch 125, and an inductive cross coupling exists between the third filtering cavity E3 and the sixth filtering cavity E6 of the fifth filtering branch 125, so as to form four cross-coupling zeros of the fifth filtering branch 125. Typically the capacitive cross-coupling element may be a flying rod. Typically the inductive cross-coupling element may be a metal stiffener. The fifth filtering branch 125 can realize zero suppression through four cross-coupling zeros of the fifth filtering branch 125, which is convenient for debugging indexes.

As shown in fig. 24, fig. 24 is a schematic topological diagram of another embodiment of the sixth filtering branch 126 provided in the present application, and eight filtering cavities of the sixth filtering branch 126 form four cross-coupling zeros of the sixth filtering branch 126. The second filter cavity F2 and the seventh filter cavity F7 of the sixth filter branch 126 are capacitively cross-coupled, the third filter cavity F3 and the seventh filter cavity F7 of the sixth filter branch 126 are capacitively cross-coupled, the third filter cavity F3 and the sixth filter cavity F6 of the sixth filter branch 126 are inductively cross-coupled, and the fourth filter cavity F4 and the sixth filter cavity F6 of the sixth filter branch 126 are inductively cross-coupled, so as to form four cross-coupled zeros of the sixth filter branch 126, which can realize zero suppression and facilitate debugging of indexes.

As shown in fig. 25, fig. 25 is a schematic topology diagram of another embodiment of the seventh filtering branch 127 provided in the present application, and eight filtering cavities of the seventh filtering branch 127 form four cross-coupling zeros of the seventh filtering branch 127. The second filtering cavity G2 and the seventh filtering cavity G7 of the seventh filtering branch 127 are coupled in a capacitive cross manner, the third filtering cavity G3 and the seventh filtering cavity G7 of the seventh filtering branch 127 are coupled in a capacitive cross manner, the third filtering cavity G3 and the sixth filtering cavity G6 of the seventh filtering branch 127 are coupled in an inductive cross manner, and the fourth filtering cavity G4 and the sixth filtering cavity G6 of the seventh filtering branch 127 are coupled in an inductive cross manner, so that four cross-coupling zeros of the seventh filtering branch 127 are formed, zero suppression can be realized, and indexes can be debugged conveniently.

As shown in fig. 26, fig. 26 is a schematic topology diagram of another embodiment of the eighth filtering branch 128 provided in the present application. The eight filter cavities of the eighth filter branch 128 form the four cross-coupling zeros of the eighth filter branch 128. Specifically, the second filter cavity H2 and the seventh filter cavity H7 of the eighth filter branch 128 are capacitively cross-coupled, the second filter cavity H2 and the sixth filter cavity H6 are capacitively cross-coupled, the third filter cavity H3 and the fifth filter cavity H5 are inductively cross-coupled, and the third filter cavity H3 and the sixth filter cavity H6 are inductively cross-coupled to form four cross-coupled zeros of the eighth filter branch 128, so that zero suppression can be realized, and indexes can be conveniently debugged.

In this embodiment, in the fifth filtering branch 125, the coupling bandwidth between the ninth port and the first filtering cavity E1 of the fifth filtering branch 125 is in the range of 26MHz to 34 MHz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 125 is in the range of 21MHz-28 MHz; the coupling bandwidth between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch 125 is in the range of 15MHz-20 MHz; the coupling bandwidth between the second filter cavity E2 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of (-3) MHz-1 MHz; the coupling bandwidth between the second filter cavity E2 and the seventh filter cavity E7 of the fifth filter branch 125 ranges from (-2) MHz to 2 MHz; the coupling bandwidth between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch 125 is in the range of 10MHz to 16 MHz; the coupling bandwidth between the third filter cavity E3 and the fifth filter cavity E5 of the fifth filter branch 125 is in the range of 8MHz to 13 MHz; the coupling bandwidth between the third filter cavity E3 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of (-1) MHz-3 MHz; the coupling bandwidth between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 125 is in the range of 9MHz-15 MHz; the coupling bandwidth between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch 125 is in the range of 15MHz-20 MHz; the coupling bandwidth between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch 125 is in the range of 21MHz-28 MHz; the coupling bandwidth between the eighth filter cavity E8 and the tenth port of the fifth filter branch 125 is in the range of 26MHz-34 MHz.

The resonant frequencies of the first filter cavity E1 to the eighth filter cavity E8 of the fifth filter branch 125 are sequentially in the following ranges: 1721MHz-1723MHz, 1721MHz-1723MHz, 1721MHz-1723MHz, 1731MHz-1733MHz, 1722MHz-1724MHz, 1721MHz-1723MHz, 1721MHz-1723MHz, 1721MHz-1723 MHz.

In this embodiment, the simulated bandwidth of the fifth filtering branch 125 is as the frequency band curve 207 in fig. 27, so that the simulated bandwidth of the fifth filtering branch 125 is within the range of 1709-1736MHz, which meets the design requirement of the filter 10, and the bandwidth of the fifth filtering branch 125 can be precisely controlled. The bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1665MHz to 1670MHz is greater than or equal to 50 dB; the bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1670MHz to 1690 is greater than or equal to 25 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 1690MHz to 1695 is greater than 10 dB; the bandwidth inhibition of the fifth filtering branch 125 in the frequency band range of 1785MHz to 1790MHz is more than 35 dB; the bandwidth suppression of the fifth filtering branch 125 in the frequency band range of 1790MHz to 1795MHz is greater than 50dB, so that the out-of-band suppression and other performances of the fifth filtering branch 125 can be improved.

In the sixth filtering branch 126, the coupling bandwidth between the eleventh port and the first filtering cavity F1 of the sixth filtering branch 126 is in the range of 26MHz-34 MHz; the coupling bandwidth between the first filter cavity F1 and the second filter cavity F2 of the sixth filter branch 126 is in the range of 21MHz-28 MHz; the coupling bandwidth between the second filter cavity F2 and the third filter cavity F3 of the sixth filter branch 126 is in the range of 15MHz-20 MHz; the coupling bandwidth between the second filter cavity F2 and the seventh filter cavity F7 of the sixth filter branch 126 ranges from (-2) MHz to 2 MHz; the coupling bandwidth between the third filter cavity F3 and the fourth filter cavity F4 of the sixth filter branch 126 ranges from 13MHz to 19 MHz; the coupling bandwidth between the third filter cavity F3 and the sixth filter cavity F6 of the sixth filter branch 126 ranges from (-1) MHz to 3 MHz; the coupling bandwidth between the third filter cavity F3 and the seventh filter cavity F7 of the sixth filter branch 126 ranges from (-3) MHz to 1 MHz; the coupling bandwidth between the fourth filter cavity F4 and the fifth filter cavity F5 of the sixth filter branch 126 is in the range of 9MHz-15 MHz; the coupling bandwidth between the fourth filter cavity F4 and the sixth filter cavity F6 of the sixth filter branch 126 is in the range of 8MHz to 13 MHz; the coupling bandwidth between the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 126 ranges from 10MHz to 16 MHz; the coupling bandwidth between the sixth filter cavity F6 and the seventh filter cavity F7 of the sixth filter branch 126 ranges from 15MHz to 20 MHz; the coupling bandwidth between the seventh filtering cavity F7 and the eighth filtering cavity F8 of the sixth filtering branch 126 ranges from 21MHz to 28 MHz; the coupling bandwidth between the eighth filter cavity F8 and the twelfth port of the sixth filter branch 126 ranges from 26MHz to 34 MHz.

The resonant frequencies of the first filter cavity F1 through the eighth filter cavity F8 of the sixth filter branch 126 are sequentially in the following ranges: 1721MHz-1723MHz, 1721MHz-1723MHz, 1721MHz-1723MHz, 1722MHz-1724MHz, 1731MHz-1733MHz, 1721MHz-1723MHz, 1721MHz-1723 MHz.

The simulation result of the sixth filtering branch 126 in this embodiment is the same as the frequency band curve 207 in fig. 27, and is not repeated here. The bandwidth that can be simulated by the sixth filtering branch 126 is within the range of 1709-1736MHz, and the bandwidth of the sixth filtering branch 126 can be precisely controlled.

The debugging index parameter of the seventh filtering branch 127 and the debugging index parameter of the sixth filtering branch 126 may be the same, and are not described herein again. The simulation result of the seventh filtering branch 127 in this embodiment is the same as the frequency band curve 207 in fig. 27, and is not described herein again. The simulated bandwidth of the seventh filtering branch 127 is within the range of 1709-1736MHz, which can accurately control the bandwidth of the seventh filtering branch 127.

The tuning index parameter of the eighth filtering branch 128 is the same as the tuning index parameter of the fifth filtering branch 125, and is not described herein again. The simulation result of the eighth filtering branch 128 in this embodiment is the same as the frequency band curve 207 in fig. 27, and is not described herein again. The bandwidth simulated by the eighth filtering branch 128 is within the range of 1709-1736MHz, which can accurately control the bandwidth of the eighth filtering branch 128.

The present application also provides a fifth embodiment of the filter, which is described on the basis of the filter 10 disclosed in the third embodiment. As shown in fig. 28, fig. 28 is a schematic structural diagram of a fifth embodiment of the filter 10 provided in the present application, and is different from the third embodiment, in this embodiment, the first filter cavity E1 to the third filter cavity E3 and the sixth filter cavity E6 to the eighth filter cavity E8 of the fifth filter branch 125 are sequentially coupled and connected, and the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 125 are reserved cavities. Namely, the fourth filter cavity F4 and the fifth filter cavity F5 of the sixth filter branch 126, the fourth filter cavity G4 and the fifth filter cavity G5 of the seventh filter branch 127, and the fourth filter cavity H4 and the fifth filter cavity H5 of the eighth filter branch 128 are reserved cavities. By providing the reserved cavities, the row cavities of the filter 10 can be adjusted as required, thereby increasing the applicability of the filter 10.

In this embodiment, as shown in fig. 29, fig. 29 is a schematic topology diagram of a further embodiment of the fifth filtering branch 125 provided in this application, specifically, capacitive cross coupling is performed between the second filtering cavity E2 and the sixth filtering cavity E6 of the fifth filtering branch 125, and capacitive cross coupling is performed between the second filtering cavity E2 and the seventh filtering cavity E7 of the fifth filtering branch 125, so as to form two capacitive cross-coupling zeros of the fifth filtering branch 125, which can implement zero suppression and facilitate debugging indexes.

As shown in fig. 30, fig. 30 is a schematic topology diagram of a further embodiment of the sixth filtering branch 126 provided in the present application, and specifically, a capacitive cross coupling exists between the second filtering cavity F2 and the seventh filtering cavity F7 of the sixth filtering branch 126, and a capacitive cross coupling exists between the third filtering cavity F3 and the seventh filtering cavity F7 of the sixth filtering branch 126, so as to form two capacitive cross-coupling zeros of the sixth filtering branch 126, which can implement zero suppression and facilitate tuning indexes.

In this embodiment, the topology diagram of the seventh filtering branch 127 is the same as the topology diagram of the sixth filtering branch 126, and is not described herein again. The topology of the eighth filtering branch 128 is the same as that of the fifth filtering branch 125, and is not described herein again.

In the fifth filtering branch 125, the coupling bandwidth between the ninth port and the first filtering cavity E1 of the fifth filtering branch 125 is in the range of 39MHz-48 MHz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 125 is in the range of 30MHz-38 MHz; the coupling bandwidth between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch 125 is in the range of 20MHz-28 MHz; the coupling bandwidth between the second filter cavity E2 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of (-9) MHz- (-4) MHz; the coupling bandwidth between the second filter cavity E2 and the seventh filter cavity E7 of the fifth filter branch 125 ranges from (-4) MHz to 1 MHz; the coupling bandwidth between the third filter cavity E3 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of 21MHz-28 MHz; the coupling bandwidth between the sixth filter cavity E6 and the seventh filter cavity E7 of the fifth filter branch 125 is in the range of 22MHz-29 MHz; the coupling bandwidth between the seventh filter cavity E7 and the eighth filter cavity E8 of the fifth filter branch 125 is in the range of 32MHz-40 MHz; the coupling bandwidth between the eighth filter cavity E8 and the tenth port of the fifth filter branch 125 is in the range of 40MHz-49 MHz.

The resonant frequencies of the six sequentially coupled filter cavities of the fifth filter branch 125 are sequentially located in the following ranges: 1717MHz-1719MHz, 1721MHz-1723MHz, 1715MHz-1717MHz, 1722MHz-1724MHz, 1721MHz-1723MHz and 1721MHz-1723 MHz.

In this embodiment, the simulated bandwidth of the fifth filtering branch 125 is as the frequency band curve 105 in fig. 14, so that the simulated bandwidth of the fifth filtering branch 125 is located in the range of 1707-1738MHz, which meets the design requirement of the filter 10, and the bandwidth of the fifth filtering branch 125 can be precisely controlled. When the frequency of the first filtering branch 121 is 1805MHz, the suppression is greater than 88 dB; when the frequency of the first filtering branch 121 is 1790MHz, the rejection is greater than 69 dB; when the frequency of the first filtering branch 121 is 1785MHz, the rejection is greater than 65 dB; when the frequency of the first filtering branch 121 is 1695mhz, the suppression is greater than 25 dB; when the frequency of the first filtering branch 121 is 1690MHz, the rejection is greater than 43 dB; the first filtering branch 121 suppresses more than 56dB at a frequency of 1670 MHz; when the frequency of the first filtering branch 121 is 1710MHz, the suppression is greater than 1 dB; when the frequency of the first filtering branch 121 is 1735MHz, the suppression is greater than 1dB, so that the out-of-band suppression performance of the fifth filtering branch 125 can be improved.

In the sixth filtering branch 126, the coupling bandwidth between the eleventh port and the first filtering cavity F1 of the sixth filtering branch 126 is in the range of 39MHz-48 MHz; the coupling bandwidth between the first filter cavity F1 and the second filter cavity F2 of the sixth filter branch 126 is in the range of 30MHz-38 MHz; the coupling bandwidth between the second filter cavity F2 and the third filter cavity F3 of the sixth filter branch 126 is in the range of 20MHz to 28 MHz; the coupling bandwidth between the second filter cavity F2 and the seventh filter cavity F7 of the sixth filter branch 126 ranges from-4 MHz to 1 MHz; the coupling bandwidth between the third filter cavity F3 and the sixth filter cavity F6 of the sixth filter branch 126 ranges from 21MHz to 28 MHz; the coupling bandwidth between the third filter cavity F3 and the seventh filter cavity F7 of the sixth filter branch 126 is in the range of (-9) MHz- (-4) MHz; the coupling bandwidth between the sixth filter cavity F6 and the seventh filter cavity F7 of the sixth filter branch 126 ranges from 22MHz to 29 MHz; the coupling bandwidth between the seventh filtering cavity F7 and the eighth filtering cavity F8 of the sixth filtering branch 126 ranges from 32MHz to 40 MHz; the coupling bandwidth between the eighth filter cavity F8 and the twelfth port of the sixth filter branch 126 ranges from 40MHz to 49 MHz.

The resonant frequencies of the six sequentially coupled filter cavities of the sixth filter branch 126 are sequentially located in the following ranges: 1717MHz-1719MHz, 1721MHz-1723MHz, 1721MHz-1723MHz, 1715MHz-1717MHz, 1721MHz-1723MHz, and 1721MHz-1723 MHz.

The simulated bandwidth of the sixth filtering branch 126 is located in the range of 1707-1738MHz, which meets the design requirement of the filter 10, and can accurately control the bandwidth of the sixth filtering branch 126. The simulation result of the sixth filtering branch 126 in this embodiment is the same as the frequency band curve 105 in fig. 14, and is not repeated here.

The debugging index parameter of the seventh filtering branch 127 may be the same as the debugging index parameter of the sixth filtering branch 126, and the simulated bandwidth of the seventh filtering branch 127 is located in the range of 1707-1738MHz, which meets the design requirement of the filter 10 and can accurately control the bandwidth of the seventh filtering branch 127. The simulation result of the seventh filtering branch 127 in this embodiment is the same as the frequency band curve 105 in fig. 14, and is not described herein again.

The debugging index parameter of the eighth filtering branch 128 may be the same as the debugging index parameter of the sixth filtering branch 126, and the simulated bandwidth of the eighth filtering branch 128 is within a range of 1707MHz to 1738MHz, so as to meet the design requirement of the filter 10, and accurately control the bandwidth of the eighth filtering branch 128. The simulated bandwidth of the eighth filtering branch 128 in this embodiment is the same as the frequency band curve 105 in fig. 14, and is not described herein again.

The present application also provides a sixth embodiment of the filter, which is described on the basis of the filter 10 disclosed in the fifth embodiment. As shown in fig. 31, fig. 31 is a schematic structural diagram of a fifth embodiment of the filter 10 provided in the present application, and unlike the fifth embodiment, in this embodiment, reserved cavities are removed from the fifth filtering branch 125, the sixth filtering branch 126, the seventh filtering branch 127, and the eighth filtering branch 128.

As shown in fig. 31, that is, the fifth filtering branch 125 is composed of six filtering cavities coupled in sequence, and the six filtering cavities of the fifth filtering branch 125 are the first filtering cavity E1 to the sixth filtering cavity E6 of the fifth filtering branch 125. The six filter cavities of the sixth filter branch 126 are the first filter cavity F1 through the sixth filter cavity F6 of the sixth filter branch 126. The six filter cavities of the seventh filter branch 127 are the first filter cavity G1 to the sixth filter cavity G6 of the seventh filter branch 127, and the six filter cavities of the eighth filter branch 128 are the first filter cavity H1 to the sixth filter cavity H6 of the eighth filter branch 128.

For details of the fifth filtering branch 125, the sixth filtering branch 126, the seventh filtering branch 127, and the eighth filtering branch 128, please refer to the description of the fifth embodiment, which is not repeated herein.

In the fifth filtering branch 125, the coupling bandwidth between the ninth port and the first filtering cavity E1 of the fifth filtering branch 125 is in the range of 20MHz-28 MHz; the coupling bandwidth between the first filter cavity E1 and the second filter cavity E2 of the fifth filter branch 125 is in the range of 17MHz-23 MHz; the coupling bandwidth between the second filter cavity E2 and the third filter cavity E3 of the fifth filter branch 125 is in the range of 10MHz-15 MHz; the coupling bandwidth between the second filter cavity E2 and the fourth filter cavity E4 of the fifth filter branch 125 is in the range of (-6) MHz- (-2) MHz; the coupling bandwidth between the second filter cavity E2 and the fifth filter cavity E5 of the fifth filter branch 125 is in the range of (-6) MHz- (-2) MHz; the coupling bandwidth between the third filter cavity E3 and the fourth filter cavity E4 of the fifth filter branch 125 is in the range of 13MHz to 19 MHz; the coupling bandwidth between the fourth filter cavity E4 and the fifth filter cavity E5 of the fifth filter branch 125 is in the range of 11MHz-16 MHz; the coupling bandwidth between the fifth filter cavity E5 and the sixth filter cavity E6 of the fifth filter branch 125 is in the range of 17MHz-23 MHz; the coupling bandwidth between the sixth filter cavity E6 and the tenth port of the fifth filter branch 125 is in the range of 21MHz-28 MHz.

The resonant frequencies of the six sequentially coupled filter cavities of the fifth filter branch 125 are sequentially located in the following ranges: 1722MHz-1724MHz, 1722MHz-1724MHz, 1718MHz-1720MHz, 1723MHz-1725MHz, 1722MHz-1724MHz, and 1722MHz-1724 MHz.

In the sixth filtering branch 126, the coupling bandwidth between the eleventh port and the first filtering cavity F1 of the sixth filtering branch 126 is in the range of 20MHz-28 MHz; the coupling bandwidth between the first filter cavity F1 and the second filter cavity F2 of the sixth filter branch 126 is in the range of 17MHz-23 MHz; the coupling bandwidth between the second filter cavity F2 and the third filter cavity F3 of the sixth filter branch 126 is in the range of 11MHz to 16 MHz; the coupling bandwidth between the second filter cavity F2 and the fifth filter cavity F5 of the sixth filter branch 126 ranges from-6 MHz to 2 MHz; the coupling bandwidth between the third filter cavity F3 and the fourth filter cavity F4 of the sixth filter branch 126 ranges from 13MHz to 19 MHz; the coupling bandwidth between the third filter cavity F3 and the fifth filter cavity F5 of the sixth filter branch 126 ranges from (-6) MHz to 2 MHz; the coupling bandwidth between the fourth filter cavity F4 and the fifth filter cavity F5 of the sixth filter branch 126 is in the range of 12MHz to 16 MHz; the coupling bandwidth between the fifth filter cavity F5 and the sixth filter cavity F6 of the sixth filter branch 126 ranges from 17MHz to 23 MHz; the coupling bandwidth between the sixth filter cavity F6 and the twelfth port of the sixth filter branch 126 ranges from 20MHz to 28 MHz.

The resonant frequencies of the six sequentially coupled filter cavities of the sixth filter branch 126 are sequentially located in the following ranges: 1722MHz-1724MHz, 1722MHz-1724MHz, 1723MHz-1725MHz, 1718MHz-1720MHz, 1722MHz-1724MHz, and 1722MHz-1724 MHz.

The simulated bandwidth of the sixth filtering branch 126 is within the range of 1709MHz-1736MHz, which meets the design requirement of the filter 10 and can accurately control the bandwidth of the sixth filtering branch 126. The simulation result of the sixth filtering branch 126 is the same as the frequency band curve 207 shown in fig. 27, and is not described herein again.

The debugging index parameter of the seventh filtering branch 127 and the debugging index parameter of the sixth filtering branch 126 may be the same, and are not described herein again. The simulation bandwidth of the seventh filtering branch 127 is within the range of 1709MHz-1736MHz, which meets the design requirement of the filter 10, and the bandwidth of the seventh filtering branch 127 can be accurately controlled. The simulation result of the seventh filtering branch 127 is the same as the frequency band curve 207 shown in fig. 27, and is not described herein again.

The tuning index parameter of the eighth filtering branch 128 may be the same as the tuning index parameter of the fifth filtering branch 125, and is not described herein again. The simulation bandwidth of the eighth filtering branch 128 is within a range of 1709MHz to 1736MHz, which meets the design requirement of the filter 10 and can accurately control the bandwidth of the eighth filtering branch 128. The simulation result of the eighth filtering branch 128 is the same as the frequency band curve 207 shown in fig. 27, and is not described herein again.

As shown in fig. 32, fig. 32 is a schematic structural diagram of an embodiment of the communication device provided in this application. The communication device of the present embodiment includes an antenna 62 and a radio frequency unit 61. The antenna 62 and the radio frequency unit 61 can be installed on a base station, and can also be installed on objects such as a street lamp; the antenna 62 is connected to a Radio Unit (RRU) 61. The radio frequency unit 61 comprises the filter disclosed in the above embodiments for filtering the radio frequency signal.

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

It should be noted that some embodiments of the present application refer to the present application as a filter, and may also be referred to as a combiner, that is, a dual-band combiner, and may also be referred to as a duplexer in other embodiments.

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 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;

the first filtering branch is arranged on the shell and consists of eight filtering cavities which are sequentially coupled;

the second filtering branch consists of eight filtering cavities which are coupled in sequence;

wherein the second filtering cavity to the eighth filtering cavity of the first filtering branch and the eight filtering cavities of the second filtering branch are divided into four rows arranged along the second direction,

the projections of the first filtering branch and the second filtering branch in the second direction are at least partially overlapped.

2. The filter of claim 1,

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

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

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

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

the projection of the center of the first filter cavity of the first filter branch in the second direction is located between the projection of the center of the second filter cavity of the first filter branch and the projection of the center of the sixth filter cavity in the second direction, and the projection of the center of the second filter cavity of the first filter branch in the first direction is located between the projection of the center of the first filter cavity of the first filter branch and the projection of the center of the sixth filter cavity in the first direction;

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

3. The filter of claim 2, further comprising a third filtering branch and a fourth filtering branch, wherein the first filtering branch, the second filtering branch, the third filtering branch and the fourth filtering branch are sequentially arranged along the second direction,

the third filtering branch consists of eight filtering cavities which are coupled in sequence,

the fourth filtering branch consists of eight filtering cavities which are coupled in sequence,

the first filtering cavity to the eighth filtering cavity of the third filtering branch and the first filtering cavity to the eighth filtering cavity of the fourth filtering branch are divided into four rows arranged along the second direction;

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

the second filtering cavity and the third filtering cavity of the fourth filtering branch circuit and the fourth filtering cavity and the seventh filtering cavity of the third filtering branch circuit are arranged in sequence along the first direction in a row;

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

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

4. The filter according to claim 3, wherein the capacitive cross coupling is performed between the second filter cavity and the fourth filter cavity of the first filter branch, between the second filter cavity and the fifth filter cavity of the first filter branch, and between the fifth filter cavity and the seventh filter cavity of the first filter branch, respectively, to form three capacitive cross coupling zeros of the first filter branch;

capacitive cross coupling is respectively performed between a second filtering cavity and a fourth filtering cavity of the second filtering branch, between the fourth filtering cavity and a seventh filtering cavity of the second filtering branch, and between a fifth filtering cavity and a seventh filtering cavity of the second filtering branch, so as to form three capacitive cross coupling zeros of the second filtering branch;

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

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

5. The filter according to claim 3, further comprising a fifth filtering branch, a sixth filtering branch, a seventh filtering branch and an eighth filtering branch, wherein the fifth filtering branch and the sixth filtering branch are disposed adjacently along the second direction and have the same structure, the seventh filtering branch and the sixth filtering branch are disposed symmetrically along the second direction, and the eighth filtering branch and the fifth filtering branch are disposed symmetrically along the second direction.

6. The filter according to claim 5, wherein the fifth filter branch consists of six filter cavities coupled in sequence and forming two capacitive cross-coupling zeros of the fifth filter branch, the six filter cavities of the fifth filter branch are divided into two columns arranged along the second direction,

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

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

and capacitive cross coupling is respectively performed between the second filtering cavity and the fourth filtering cavity of the fifth filtering branch and between the second filtering cavity and the fifth filtering cavity of the fifth filtering branch so as to form two capacitive cross coupling zeros of the fifth filtering branch.

7. The filter according to claim 5, characterized in that the fifth filtering branch consists of eight filtering cavities arranged in sequence,

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

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

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

8. The filter according to claim 7, wherein the first filter cavity to the eighth filter cavity of the fifth filter branch are sequentially coupled, the second filter cavity and the sixth filter cavity of the fifth filter branch are capacitively cross-coupled, the second filter cavity and the seventh filter cavity of the second filter branch are capacitively cross-coupled, the third filter cavity and the fifth filter cavity of the fifth filter branch are inductively cross-coupled, and the third filter cavity and the sixth filter cavity of the fifth filter branch are inductively cross-coupled, so as to form four cross-coupling zeros of the fifth filter branch.

9. The filter according to claim 7, wherein the fourth filtering cavity and the fifth filtering cavity of the fifth filtering branch are reserved cavities, the first filtering cavity to the third filtering cavity and the sixth filtering cavity to the eighth filtering cavity of the fifth filtering branch are sequentially coupled, and capacitive cross coupling is performed between the second filtering cavity and the sixth filtering cavity of the fifth filtering branch and between the second filtering cavity and the seventh filtering cavity of the fifth filtering branch respectively to form two capacitive cross coupling zeros of the fifth filtering branch.

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