CN113036368A

CN113036368A - Communication system and filter thereof

Info

Publication number: CN113036368A
Application number: CN201911361412.7A
Authority: CN
Inventors: 周峰; 李华; 王磊; 刘学鑫
Original assignee: Shenzhen Tatfook Technology Co Ltd
Current assignee: Shenzhen Tatfook Technology Co Ltd
Priority date: 2019-12-25
Filing date: 2019-12-25
Publication date: 2021-06-25

Abstract

The application discloses a communication system and a filter thereof, wherein the filter comprises a shell, a first side and a second side, wherein the first side and the second side are perpendicular to each other; the first filtering branch is arranged on one side of the shell and consists of eight filtering cavities which are sequentially coupled, the eight filtering cavities of the first filtering branch further form four cross-coupling zero points, and the eight filtering cavities of the first filtering branch are divided into two rows which are arranged along the second direction; the eight filter cavities of the first filter branch circuit are arranged in a b shape in sequence. In this way, the filter cavity arrangement rule of this application does benefit to miniaturization and overall arrangement, can improve the stability of wave filter.

Description

Communication system and filter thereof

Technical Field

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

Background

In a mobile communication system, a desired signal is modulated to form a modulated signal, the modulated signal is carried on a high-frequency carrier signal, the modulated signal is transmitted to the air through a transmitting antenna, the signal in the air is received through a receiving antenna, and the signal received by the receiving antenna does not include the desired signal but also includes harmonics and noise signals of other frequencies. The signal received by the receiving antenna needs to be filtered by a filter to remove unnecessary harmonic and noise signals. Therefore, the designed filter must precisely control its bandwidth.

The inventor of the present application found in long-term research and development work that the arrangement of the filter cavities in the current filter is irregular, resulting in the filter being disadvantageous for miniaturization and layout.

Disclosure of Invention

The present application provides a communication system and a filter thereof to solve the above problems in the prior art.

In order to solve the above technical problem, 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 one side of the shell and consists of eight filtering cavities which are coupled in sequence, the eight filtering cavities of the first filtering branch further form four cross-coupling zero points, and the eight filtering cavities of the first filtering branch are divided into two columns which are arranged along the second direction.

In order to solve the technical problem, the present application provides a communication system, where the communication system includes a terminal and a base station, and the terminal communicates with other terminals through the base station; the base station comprises a base station antenna and a radio frequency unit, the base station antenna is connected with the radio frequency unit, the radio frequency unit comprises the filter, and the filter is used for filtering radio frequency signals.

Compared with the prior art, the filter of this application includes: a housing having a first direction and a second direction perpendicular to each other; the first filtering branch is arranged on one side of the shell and consists of eight filtering cavities which are sequentially coupled, the eight filtering cavities of the first filtering branch further form four cross-coupling zero points, and the eight filtering cavities of the first filtering branch are divided into two rows which are arranged along the second direction; the eight filter cavities of the first filter branch circuit are arranged in a b shape in sequence. Due to the special arrangement mode of the filter cavities of the filter, gaps among different filter branches can be mutually filled, and the miniaturization and the layout of the multi-branch filter are facilitated; the filter can flexibly adjust the indexes of the row cavities and improve the intermodulation of the zero point.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced 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 based on these drawings without creative efforts.

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

FIG. 2 is a schematic diagram of a first filter branch topology of a filter according to the present application;

FIG. 3 is a schematic diagram of another embodiment of the filter of the present application;

FIG. 4 is a schematic diagram of a second filter branch topology of the filter of the present application;

FIG. 5 is a schematic diagram of a filter according to another embodiment of the present application;

FIG. 6 is a schematic diagram of a fourth filter branch topology of the filter of the present application;

FIG. 7 is a diagram showing simulation results of the filter of the present application;

FIG. 8 is a schematic diagram of a filter according to another embodiment of the present application;

fig. 9 is a schematic structural diagram of an embodiment of the communication system of the present application.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present application, a communication system and a filter thereof provided by the present invention are further described in detail below with reference to the accompanying drawings and the detailed description.

The present application provides a filter, as shown in fig. 1, fig. 1 is a schematic structural diagram of an embodiment of the filter of the present application. The filter 10 of the present embodiment includes a housing 11 and a first filter branch 12; the first filter branch 12 may be a receive filter branch or a transmit filter branch.

The housing 11 has a first direction L and a second direction D, and the first direction L of the housing 11 is perpendicular to the second direction D of the housing 11. The first filtering branch 12 is arranged on one side of the housing 11 and is composed of eight filtering cavities 121 coupled in sequence, and the eight filtering cavities 121 further form four cross-coupling zeros 122; the four cross-coupling zeros 122 may be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, which can realize zero suppression and facilitate debugging indexes; the eight filter chambers 121 are divided into two rows arranged in the second direction D; the eight filter cavities of the first filter branch are arranged in a b shape in sequence.

The first filtering branch 12 includes first through eighth filtering cavities R11 through R18, and the first through eighth filtering cavities R11 through R18 are divided into two columns arranged in the second direction D. Specifically, the eighth filter cavity R18, the seventh filter cavity R17, the sixth filter cavity R16, the fifth filter cavity R15 and the fourth filter cavity R14 of the first filter branch 12 are in a row and are sequentially arranged along the first direction L; the first filter cavity R11, the second filter cavity R12 and the third filter cavity R13 of the first filter branch 12 are in a row and are sequentially arranged along the first direction L.

The fifth filter cavity R15 of the first filter branch 12 is further disposed adjacent to the sixth filter cavity R16, the second filter cavity R12, the third filter cavity R13 and the fourth filter cavity R14 of the first filter branch 12, respectively. As shown in fig. 1, eight filter cavities 121 of the filter 10 are regularly distributed, so that the volume of the filter 10 can be reduced, and the cost can be reduced; in production, a plurality of filters 10 can be manufactured by using the same set of die, so that miniaturization and layout are facilitated; the filter 10 can flexibly adjust the indexes of the row cavities and improve the intermodulation of the zero point.

As shown in fig. 1 and fig. 2, fig. 2 is a schematic diagram of a first filtering branch topology of the filter of the present application. Capacitive cross coupling is respectively performed between the first filter cavity R11 and the sixth filter cavity R16, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12, so that three capacitive cross coupling zeros are formed; the third filter cavity R13 and the fifth filter cavity R15 of the first filter branch 12 are inductively cross-coupled to form an inductive cross-coupling zero.

Specifically, a window may be disposed between the third filter cavity R13 and the fifth filter cavity R15 of the first filter branch 12, and a metal coupling rib is disposed on the window, so that the third filter cavity R13 and the fifth filter cavity R15 of the first filter branch 12 implement inductive cross coupling, and form an inductive cross coupling zero.

Windows can be respectively arranged between the first filter cavity R11 and the sixth filter cavity R16, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12, so that capacitive cross coupling is realized between the first filter cavity R11 and the sixth filter cavity R16, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12, and a capacitive cross coupling zero point is formed.

In some embodiments, capacitive zero coupling may also be achieved by providing capacitive cross-coupling elements. The capacitive cross-coupling element may be a flying rod, that is, a flying rod is arranged between the first filter cavity R11 and the sixth filter cavity R6, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12. As shown in fig. 1, since the distances between the first filter cavity R11 and the sixth filter cavity R16, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12 are equal, the flying rod elements with the same specification can be used to achieve the effect of realizing three capacitive coupling zeros. The filtering branch can reduce the types of materials, is convenient to manufacture, reduces the complexity of products and saves the cost.

The inductive cross coupling is equivalent to connecting an inductor between the third filter cavity R13 and the fifth filter cavity R15 of the first filter branch 12; the capacitive cross coupling is equivalent to connecting capacitances between the first filter cavity R11 and the sixth filter cavity R16, between the second filter cavity R12 and the sixth filter cavity R16, and between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12, respectively. The inductive cross coupling and the capacitive cross coupling can realize zero point suppression, so that the debugging index is convenient, and the designed filter meets the parameter requirement.

Furthermore, the eight filter cavities 121 of the first filter branch 12 may be equally sized. Namely, the eight filter cavities 121 can be distributed equidistantly, which is convenient for layout and debugging, and improves the consistency of the filter 10; the distance between two adjacent filtering cavities is equal, and the eight filtering cavities are closely arranged, so that the space utilization rate can be further improved, and the size is reduced.

The first filtering branch of this embodiment is composed of eight filtering cavities coupled in sequence, the eight filtering cavities of the first filtering branch further form four cross-coupling zeros, and the eight filtering cavities of the first filtering branch are divided into two rows arranged along the second direction; because the filter cavities of the filter are regularly arranged, the filter can be manufactured by the same set of die in production, thereby being beneficial to miniaturization and layout; the filter can flexibly adjust the indexes of the row cavities and improve the intermodulation of the zero point.

Optionally, one side of the housing 11 is further provided with a first port (not shown) and a second port (not shown), the first filter cavity R11 of the first filter branch 11 is connected with the first port, and the eighth filter cavity R18 is connected with the second port. Wherein the first port and the second port may both be taps of the filter 10.

Referring to fig. 3 and fig. 4, fig. 3 is a schematic structural diagram of another embodiment of the filter of the present application, and fig. 4 is a schematic structural diagram of a second filtering branch of the filter of the present application. The filter 10 of the present embodiment includes a housing 11, a first filter branch 12 and a second filter branch 13. The same components in this embodiment as those in the above embodiments are not described herein again.

The second filtering branch 13 is composed of eight filtering cavities 131 coupled in sequence, and further forms two cross-coupling zeros 132; the first filter cavity T11 of the second filter branch 13 is further arranged adjacent to the first filter cavity R11 and the eighth filter cavity R18 of the first filter branch 12, respectively. The second filter branch 13 may be a receive filter branch or a transmit filter branch.

The second filtering branch 13 includes first through eighth filter cavities T11 through T18. Eight filter cavities of the second filter branch are arranged in a 9 shape in sequence. Specifically, the first filter cavity T11, the second filter cavity T12 and the eighth filter cavity R18 of the second filter branch 13 are arranged in a triangle, a projection of the center of the first filter cavity T11 of the second filter branch 13 in the second direction D is located between a projection of the center of the eighth filter cavity R18 of the first filter branch 12 and a projection of the center of the second filter cavity T12 of the second filter branch 13 in the second direction D, and a projection of the center of the eighth filter cavity R18 of the first filter branch 12 in the first direction L is located between a projection of the center of the second filter cavity T12 of the second filter branch 13 and a projection of the center of the first filter cavity T11 of the second filter branch 13 in the first direction L.

The second through eighth filter cavities T12 through T18 of the second filter branch 13 are divided into four columns arranged in the first direction L; the second filtering cavities T12 of the second filtering branch 13 are in one row; the fourth filtering cavities T14 and the third filtering cavities T13 of the second filtering branch 12 are in a row and are sequentially arranged along the second direction D; the fifth filter cavity T15 and the sixth filter cavity T16 of the second filter branch 12 are in a row and are sequentially arranged along the second direction D; the eighth filtering cavity T18 and the seventh filtering cavity T17 of the second filtering branch 13 are in a row and are sequentially arranged along the second direction D;

the sixth filtering cavity T16 of the second filtering branch 13 is further disposed adjacent to the seventh filtering cavity T17, the eighth filtering cavity T18, the fifth filtering cavity T15, the fourth filtering cavity T14 and the third filtering cavity T13 of the second filtering branch 13, respectively; the second filter cavity T12 of the second filter branch 13 is further arranged adjacent to the first filter cavity T11 and the third filter cavity T13 of the second filter branch 13, respectively.

As shown in fig. 4, the fourth filter cavity T14 and the sixth filter cavity T16 of the second filter branch 13 and the sixth filter cavity T16 and the eighth filter cavity T18 are capacitively cross-coupled to form two capacitive cross-coupling zeros, respectively.

In this embodiment, the filter includes a first filtering branch and a second filtering branch, and both the first filtering branch and the second filtering branch are provided with cross-coupling zeros, which can realize zero suppression, thereby maintaining high isolation between the first signal of the first filtering branch and the second signal of the second filtering branch. Meanwhile, due to the special arrangement mode of the first filtering branch and the second filtering branch, gaps among different filtering branches can be mutually filled, limited space is fully utilized, and miniaturization and layout of the multi-branch filter are facilitated; the filter can flexibly adjust the indexes of the row cavities and improve the intermodulation of the zero point.

Referring to fig. 5 and fig. 6, fig. 5 is a schematic structural diagram of another embodiment of the filter of the present application, and fig. 6 is a schematic structural diagram of a fourth filtering branch of the filter of the present application. The filter 10 in this embodiment includes a housing 11, a first filtering branch 12, a second filtering branch 13, a third filtering branch 14, and a fourth filtering branch 15. The same parts in this embodiment as those in the above embodiments are not described herein again. The third filtering branch 14 may be a receiving filtering branch or a transmitting filtering branch, and the fourth filtering branch 15 may be a receiving filtering branch or a transmitting filtering branch. The eight filter cavities of the fourth filter branch can also be arranged in a sequence in a shape of a '9'.

In the present embodiment, the third filtering branch 14 has the same structure as the first filtering branch 12. The third filtering branch 14 is composed of eight filtering cavities 141 coupled in sequence, and further forms four cross-coupling zeros 142; the four cross-coupling zeros 142 may be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, and the eight filter cavities 141 are divided into two rows arranged along the second direction D; the fourth filtering branch 15 is composed of eight filtering cavities 151 coupled in sequence, and further forms two cross-coupling zeros 152.

The third filter branch 14 comprises a first R21 to an eighth R28 filter cavity and the fourth filter branch 15 comprises a first T21 to an eighth T28 filter cavity. The eighth filter cavity R28 of the third filter branch 14 is further disposed adjacent to the second filter cavity T12 of the second filter branch 13, the first filter cavity T21 of the fourth filter branch 15, and the seventh filter cavity R27 of the third filter branch 14, respectively; the second to seventh filter chambers T22 to T27 of the fourth filter branch 15 and the second to eighth filter chambers T12 to T18 of the second filter branch 13 are divided into four columns arranged in the first direction L.

Specifically, in the third filter branch 14, the first through eighth filter cavities R21 through R28 are divided into two columns arranged in the second direction D. The eighth filter cavity R28, the seventh filter cavity R27, the sixth filter cavity R26, the fifth filter cavity R25 and the fourth filter cavity R24 are in a row and are sequentially arranged along the first direction L; the first filter cavity R21, the second filter cavity R22 and the third filter cavity R23 are in a row and are sequentially arranged along the first direction L.

The fifth filter cavity R25 of the third filter branch 14 is further disposed adjacent to the sixth filter cavity R26, the second filter cavity R22, the third filter cavity R23 and the fourth filter cavity R24 of the third filter branch 14, respectively.

The second filter cavity T12 of the second filter branch 13 and the second filter cavity T22 of the fourth filter branch 15 are in a row and are arranged at intervals along the second direction D; the fourth filter cavity T14 and the third filter cavity T13 of the second filter branch 13, and the fourth filter cavity T24 and the third filter cavity T23 of the fourth filter branch 15 are in a row and are sequentially arranged along the second direction D; the fifth filter cavity T15 and the sixth filter cavity T16 of the second filter branch 13, and the sixth filter cavity T26 and the fifth filter cavity T25 of the fourth filter branch 15 are in a row and are sequentially arranged along the second direction D; the eighth filter cavity T18, the seventh filter cavity T17 of the second filter branch 13 and the seventh filter cavity T27 of the fourth filter branch 15 are arranged in a row in the second direction D.

The seventh filtering cavity T27 of the fourth filtering branch 15 is further disposed adjacent to the seventh filtering cavity T17 of the second filtering branch 13, the sixth filtering cavity T26 of the fourth filtering branch 15, the fifth filtering cavity T25, and the eighth filtering cavity T28, respectively; the fourth filter cavity T24 of the fourth filter branch 15 is further disposed adjacent to the third filter cavity T13 of the second filter branch 13, the sixth filter cavity T26 of the fourth filter branch 15, the fifth filter cavity T25 and the third filter cavity T23, respectively.

Capacitive cross coupling is respectively performed between the first filter cavity R21 and the sixth filter cavity R26, between the second filter cavity R22 and the sixth filter cavity R26, and between the second filter cavity R22 and the fifth filter cavity R25 of the third filter branch 14, so that three capacitive cross coupling zeros are formed; the third filter cavity R23 and the fifth filter cavity R25 of the third filter branch 14 are inductively cross-coupled to form an inductive cross-coupling zero. The structure of the third filtering branch 14 is the same as that of the first filtering branch 12, so the topology of the third filtering branch 14 can be referred to the topology of the first filtering branch 12.

As shown in fig. 6, the third filter cavity T23 and the fifth filter cavity T25 of the fourth filter branch 15 and the fifth filter cavity T25 and the seventh filter cavity T27 are capacitively cross-coupled to form two capacitive cross-coupling zeros, respectively.

In this embodiment, the filter includes four filtering branches, which can filter multiple signals, thereby improving the filtering efficiency; the first filtering branch and the third filtering branch have the same structure and can be manufactured by the same die in production, so that the production cost is saved; the second filtering branch and the fourth filtering branch are divided into four columns arranged along the first direction, and the arrangement is regular, so that the layout and the miniaturization are facilitated.

To visually represent the effect of the filter in this embodiment, please refer to fig. 7, and fig. 7 is a diagram illustrating the simulation result of the filter of the present application. In this embodiment, the first filtering branch 12 and the third filtering branch 14 may be receiving filtering branches, and the second filtering branch 13 and the fourth filtering branch 15 may be transmitting filtering branches.

The bandwidth of the first filtering branch 12 is in the range 702Mhz-734 Mhz. In particular, the coupling bandwidth between the input and the first filter cavity R11 of the first filter branch 12 ranges from 29.5Mhz to 37 Mhz; the coupling bandwidth between the first filter cavity R11 and the second filter cavity R12 of the first filter branch 12 ranges from 23.2Mhz to 30 Mhz; the coupling bandwidth between the first filter cavity R11 and the sixth filter cavity R16 of the first filter branch 12 ranges from-3 Mhz to 1.1 Mhz; the coupling bandwidth between the second filter cavity R12 and the third filter cavity R13 of the first filter branch 12 ranges from 14.2Mhz to 20 Mhz; the coupling bandwidth between the second filter cavity R12 and the fifth filter cavity R15 of the first filter branch 12 ranges from-4 Mhz to 0.2 Mhz; the coupling bandwidth between the second filter cavity R12 and the sixth filter cavity R16 of the first filter branch 12 ranges from-1.6 Mhz to-6 Mhz; the coupling bandwidth between the third filter cavity R13 and the fourth filter cavity R14 of the first filter branch 12 ranges from 10.6Mhz to 16 Mhz; the coupling bandwidth between the third filter cavity R13 and the fifth filter cavity R15 of the first filter branch 12 ranges from 12.4Mhz to 18 Mhz; the coupling bandwidth between the fourth filter cavity R14 and the fifth filter cavity R15 of the first filter branch 12 ranges from 7.9Mhz to 13 Mhz; the coupling bandwidth between the fifth filter cavity R15 and the sixth filter cavity R16 of the first filter branch 12 ranges from 13.3Mhz to 19 Mhz; the coupling bandwidth between the sixth filter cavity R16 and the seventh filter cavity R17 of the first filter branch 12 ranges from 15.1Mhz to 21 Mhz; the coupling bandwidth between the seventh filter cavity R17 and the eighth filter cavity R18 of the first filter branch 12 ranges from 23.2Mhz to 30 Mhz; the coupling bandwidth between the eighth filter cavity R18 of the first filter branch 12 and the output terminal is in the range of 29.5Mhz-37 Mhz; therefore, the bandwidth of the first filtering branch 12 of the filter 10 of the present embodiment is located at 702Mhz-734Mhz, which can meet the design requirement.

Therefore, the resonant frequencies of the first filter cavity R12 through the eighth filter cavity R18 of the first filter branch 12 are sequentially in the following ranges: 716Mhz-718Mhz, 717Mhz-719Mhz, 715Mhz-717Mhz, 729Mhz-731Mhz, 717Mhz-719Mhz, 716Mhz-718 Mhz. Therefore, the resonant frequencies of the filter cavities are basically the same, and the convenience of manufacturing and debugging is improved; the method can be manufactured by adopting the same specification parameters, and the required parameter range can be reached only by simple debugging in the actual process.

The first filtering branch 12 and the third filtering branch 14 have the same structure and the same parameters, so the parameters of the third filtering branch 14 can be set according to the parameters of the first filtering branch 12, and are not described herein again.

The bandwidth of the second filtering branch 13 lies in the range of 757Mhz-789 Mhz. In particular, the coupling bandwidth between the input and the first filter cavity T11 of the second filter branch 13 ranges from 34.9Mhz to 43 Mhz; the coupling bandwidth between the first filter cavity T11 and the second filter cavity T12 of the second filter branch 13 ranges from 27.7Mhz to 35 Mhz; the coupling bandwidth between the second filter cavity T12 and the third filter cavity T13 of the second filter branch 13 ranges from 18.7Mhz to 25 Mhz; the coupling bandwidth between the third filter cavity T13 and the fourth filter cavity T14 of the second filter branch 13 ranges from 16.9Mhz to 23 Mhz; the coupling bandwidth between the fourth filter cavity of the second filter branch 13 and the fifth filter cavity T15 of T14 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the fourth filter cavity T14 and the sixth filter cavity T16 of the second filter branch 13 ranges from-3.4 Mhz to-8 Mhz; the coupling bandwidth between the fifth filter cavity T15 and the sixth filter cavity T16 of the second filter branch 13 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the sixth filter cavity T16 and the seventh filter cavity T17 of the second filter branch 13 ranges from 16.9Mhz to 23 Mhz; the coupling bandwidth range between the sixth filter cavity T16 and the eighth filter cavity T18 of the second filter branch 13 is-5.2 Mhz to-10 Mhz; the coupling bandwidth between the seventh filter cavity T17 and the eighth filter cavity T18 of the second filter branch 31 ranges from 26.8Mhz to 34 Mhz; the coupling bandwidth between the eighth filter cavity T18 of the second filter branch 13 and the output terminal is in the range of 34.9Mhz-43 Mhz; therefore, the bandwidth of the second filtering branch 13 of the filter 10 of the present embodiment is located at 757Mhz-789Mhz, which can meet the design requirement.

Therefore, the resonant frequencies of the first filter cavity T11 through the eighth filter cavity T18 of the second filter branch 13 are sequentially located in the following ranges: 770Mhz-772Mhz, 771Mhz-773Mhz, 765Mhz-767Mhz, 770Mhz-772 Mhz. Therefore, the resonant frequencies of the filter cavities are basically the same, and the convenience of manufacturing and debugging is improved; the method can be manufactured by adopting the same specification parameters, and the required parameter range can be reached only by simple debugging in the actual process.

The bandwidth of the fourth filtering branch 15 lies in the range of 757Mhz-789 Mhz. In particular, the coupling bandwidth between the input and the first filter cavity T21 of the fourth filter branch 15 ranges from 34.9Mhz to 43 Mhz; the coupling bandwidth between the first filter cavity T21 and the second filter cavity T22 of the fourth filter branch 15 ranges from 27.7Mhz to 35 Mhz; the coupling bandwidth between the second filter cavity T22 and the third filter cavity T23 of the fourth filter branch 15 ranges from 18.7Mhz to 25 Mhz; the coupling bandwidth between the third filter cavity T23 and the fourth filter cavity T24 of the fourth filter branch 15 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the third filter cavity T23 and the fifth filter cavity T25 of the fourth filter branch 15 ranges from-3.4 Mhz to-8 Mhz; the coupling bandwidth between the fourth filter cavity T24 and the fifth filter cavity T25 of the fourth filter branch 15 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the fifth filter cavity T25 and the sixth filter cavity T26 of the fourth filter branch 15 ranges from 16Mhz to 22 Mhz; the coupling bandwidth between the fifth filter cavity T25 and the seventh filter cavity T27 of the fourth filter branch 15 ranges from-2.5 Mhz to-7 Mhz; the coupling bandwidth between the sixth filter cavity T26 and the seventh filter cavity T27 of the fourth filter branch 15 ranges from 17.8Mhz to 24 Mhz; the coupling bandwidth between the seventh filter cavity T27 and the eighth filter cavity T28 of the fourth filter branch 15 ranges from 27.7Mhz to 35 Mhz; the coupling bandwidth between the eighth filter cavity T28 of the fourth filter branch 15 and the output terminal is in the range of 34.9Mhz-43 Mhz; therefore, the bandwidth of the fourth filtering branch 15 of the filter 10 of the present embodiment is located at 757Mhz-789Mhz, which can meet the design requirement.

Therefore, the resonant frequencies of the first filter cavity T21 through the eighth filter cavity T28 of the fourth filter branch 15 are sequentially located in the following ranges: 770Mhz-772Mhz, 771Mhz-773Mhz, 765Mhz-767Mhz, 770Mhz-772Mhz, and 770Mhz-772 Mhz. The resonant frequencies of the filter cavities of the third filter branch 14 and the fourth filter branch 15 are basically the same, so that the convenience of manufacturing and debugging is improved; the method can be manufactured by adopting the same specification parameters, and the required parameter range can be reached only by simple debugging in the actual process.

Continuing to refer to fig. 7, experimental tests have shown that the transmission bandwidth of the filter 10 of the present application is in the range of 757Mhz-789Mhz, and as shown by the band curve 20 in fig. 7, the rejection of the transmission bandwidth is satisfied: 733MHz is more than 104dB, and 798MHz is more than 16 dB. In this embodiment, the second filtering branch 13 and the fourth filtering branch 15 have different structures, but the same bandwidth can be realized after parameter debugging.

The receive bandwidth of the filter 10 of the present application is in the range of 702Mhz-734Mhz, as shown by the band curve 30 in fig. 7. Zeros a and B may be cross-coupling zeros of first filter branch 12. In the present application, the cross-coupling zeroes may coincide, so that the four cross-couplings shown in fig. 1 form zeroes a and B of the mid-band curve 30 of fig. 7. At zero a, the rejection of the reception bandwidth satisfies: 698MHz > 25 dB; at zero B, the rejection of the reception bandwidth satisfies: 738MHz > 40 dB.

In addition, the housing may include at least a first cavity and a second cavity, the first cavity may be provided with first to fourth filtering branches, and the second cavity may be provided with fifth to eighth filtering branches.

The filter branch in the first cavity may be the same as the filter branch in the second cavity. Specifically, the first filtering branch and the fifth filtering branch have the same structure, the second filtering branch and the sixth filtering branch have the same structure, the third filtering branch and the seventh filtering branch have the same structure, and the fourth filtering branch and the eighth filtering branch have the same structure.

For example, please refer to fig. 8, fig. 8 is a schematic structural diagram of a filter according to another embodiment of the present application. The housing 11 includes a first chamber 111, a second chamber 112, and a third chamber 113. A first filtering branch 12 to a fourth filtering branch 15 are arranged in the first cavity 111, a fifth filtering branch 22 to an eighth filtering branch 25 are arranged in the second cavity 112, and a ninth filtering branch 32 to a twelfth filtering branch 35 are arranged in the third cavity 113. The same parts of this embodiment as those of the above embodiment will not be described herein again.

Therein, the second cavity 112 includes a fifth filtering branch 22, a sixth filtering branch 23, a seventh filtering branch 24 and an eighth filtering branch 25. The third cavity 113 comprises a ninth filtering branch 32, a tenth filtering branch 33, an eleventh filtering branch 34 and a twelfth filtering branch 35.

The four filter branches in the first cavity 111, the four filter branches in the second cavity 112, and the four filter branches in the third cavity 113 are the same. Specifically, the first filtering branch 12 and the third filtering branch 14 in the first cavity 111, the fifth filtering branch 22 and the seventh filtering branch 24 in the second cavity 112, the ninth filtering branch 32 and the eleventh filtering branch 34 in the third cavity 113 have the same structure. The second filtering branch 13 in the first cavity 111 and the tenth filtering branch 33 in the third cavity 113 of the sixth filtering branch 23 in the second cavity 112 have the same structure. The fourth filtering branch 15 in the first cavity 111, the eighth filtering branch 25 in the second cavity 112, and the twelfth filtering branch 35 in the third cavity 113 have the same structure.

In the second cavity 112, the fifth filtering branch 22 is composed of eight filtering cavities 221 coupled in sequence, and further forms four cross-coupling zeros 222; the four cross-coupling zeroes 222 can be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, and the eight filter cavities 221 are divided into two columns arranged along the second direction D.

The fifth filtering branch 22 comprises a first filtering cavity R31 to an eighth filtering cavity R38, and the first filtering cavity R31 and the sixth filtering cavity R36, the second filtering cavity R32 and the sixth filtering cavity R36, and the second filtering cavity R32 and the fifth filtering cavity R35 of the fifth filtering branch 22 are respectively capacitively cross-coupled to form three capacitive cross-coupling zeros; the third filter cavity R33 and the fifth filter cavity R35 of the fifth filter branch 22 are inductively cross-coupled to form an inductive cross-coupling zero.

The seventh filtering branch 24 is composed of eight filtering cavities 241 coupled in sequence, and further forms four cross-coupling zeros 242; the four cross-coupling zeroes 242 can be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, and the eight filter cavities 241 are divided into two columns arranged along the second direction D.

The seventh filtering branch 24 comprises a first filtering cavity R41-an eighth filtering cavity R48, and the first filtering cavity R41 and the sixth filtering cavity R46, the second filtering cavity R42 and the sixth filtering cavity R46, and the second filtering cavity R42 and the fifth filtering cavity R45 of the seventh filtering branch 24 are respectively in capacitive cross coupling to form three capacitive cross coupling zeros; the third filter cavity R43 and the fifth filter cavity R45 of the seventh filter branch 24 are inductively cross-coupled to form an inductive cross-coupling zero.

The sixth filtering branch 23 is composed of eight filtering cavities 231 coupled in sequence, and further forms two cross-coupling zeros 232. The sixth filtering branch 23 includes first through eighth filtering cavities T31 through T38. Capacitive cross coupling is respectively formed between the fourth filter cavity T34 and the sixth filter cavity T36, and between the sixth filter cavity T36 and the eighth filter cavity T38 of the sixth filter branch 23, so as to form two capacitive cross-coupling zeros.

The eighth filtering branch 25 is composed of eight filtering cavities 251 coupled in sequence, and further forms two cross-coupling zeros 252. The eighth filtering branch 25 includes first through eighth filtering cavities T41 through T48. Capacitive cross coupling is respectively formed between the third filter cavity T43 and the fifth filter cavity T45, and between the fifth filter cavity T45 and the seventh filter cavity T47 of the eighth filter branch 25, so that two capacitive cross-coupling zeros are formed.

In the third cavity 113, the ninth filtering branch 32 is composed of eight filtering cavities 321 coupled in sequence, and further forms four cross-coupling zeros 322; the four cross-coupling zeroes 322 can be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, and the eight filter cavities 321 are divided into two columns arranged along the second direction D.

The ninth filtering branch 32 comprises a first filtering cavity R51 to an eighth filtering cavity R58, and the first filtering cavity R51 and the sixth filtering cavity R56, the second filtering cavity R52 and the sixth filtering cavity R56, and the second filtering cavity R52 and the fifth filtering cavity R55 of the ninth filtering branch 32 are respectively capacitively cross-coupled to form three capacitive cross-coupling zeros; the third filter cavity R53 and the fifth filter cavity R55 of the ninth filter branch 32 are inductively cross-coupled to form an inductive cross-coupling zero.

The eleventh filtering branch 34 is composed of eight filtering cavities 341 coupled in sequence, and further forms four cross-coupling zeros 342; the four cross-coupling zeroes 342 can be at least one inductive cross-coupling zero and at least one capacitive cross-coupling zero, and the eight filter cavities 341 are divided into two columns arranged along the second direction D.

The eleventh filtering branch 34 comprises a first filtering cavity R61 to an eighth filtering cavity R68, and capacitive cross coupling is respectively performed between the first filtering cavity R61 and the sixth filtering cavity R66, between the second filtering cavity R62 and the sixth filtering cavity R66, and between the second filtering cavity R62 and the fifth filtering cavity R65 of the eleventh filtering branch 34, so as to form three capacitive cross coupling zeros; the third filter cavity R63 and the fifth filter cavity R65 of the eleventh filter branch 34 are inductively cross-coupled to form an inductive cross-coupling zero.

The tenth filtering branch 33 is composed of eight filtering cavities 331 coupled in sequence, and further forms two cross-coupling zeros 332. The tenth filtering branch 33 includes first through eighth filtering cavities T51 through T58. Capacitive cross coupling is respectively formed between the fourth filter cavity T54 and the sixth filter cavity T56, and between the sixth filter cavity T56 and the eighth filter cavity T58 of the tenth filter branch 33, so as to form two capacitive cross-coupling zeros.

The twelfth filtering branch 35 is composed of eight filtering cavities 351 coupled in sequence, and further forms two cross-coupling zeros 352. The twelfth filtering branch 35 includes first through eighth filtering cavities T61 through T68. Capacitive cross coupling is respectively formed between the third filter cavity T63 and the fifth filter cavity T65, and between the fifth filter cavity T65 and the seventh filter cavity T67 of the twelfth filter branch 35, so as to form two capacitive cross-coupling zeros.

With reference to fig. 8, the first filtering branch 12 and the third filtering branch 14 in the first cavity 111, the fifth filtering branch 22 and the seventh filtering branch 24 in the second cavity 112, the ninth filtering branch 32 and the eleventh filtering branch 34 in the third cavity 113 are sequentially arranged along the second direction D.

The second filtering branch 13 and the fourth filtering branch 15 in the first cavity 111, the sixth filtering branch 23 and the eighth filtering branch 25 in the second cavity 112, the tenth filtering branch 33 and the twelfth filtering branch 35 in the third cavity 113 are divided into five rows along the first direction L.

The eighth filtering cavity T28 of the fourth filtering branch 15, the eighth filtering cavity T48 of the eighth filtering branch 25, and the eighth filtering cavity T68 of the twelfth filtering branch 35 are in a row and are sequentially arranged at intervals along the second direction D.

The eighth filter cavity T18, the seventh filter cavity T17 of the second filter branch 13, the seventh filter cavity T27 of the fourth filter branch 15, the eighth filter cavity T38, the seventh filter cavity T37 of the sixth filter branch 23, the seventh filter cavity T47 of the eighth filter branch 25, the eighth filter cavity T58, the seventh filter cavity T57 of the tenth filter branch 33, and the seventh filter cavity T67 of the twelfth filter branch 35 are in a row and are sequentially arranged at intervals along the second direction D.

The fifth filter cavity T15 and the sixth filter cavity T16 of the second filter branch 13, the sixth filter cavity T26 and the fifth filter cavity T25 of the fourth filter branch 15, the fifth filter cavity T35 and the sixth filter cavity T36 of the fourth filter branch 23, the sixth filter cavity T46 and the fifth filter cavity T45 of the eighth filter branch 25, the fifth filter cavity T55 and the sixth filter cavity T56 of the tenth filter branch 33, the sixth filter cavity T66 and the fifth filter cavity T65 of the twelfth filter branch 35 are in a row and are sequentially arranged at intervals along the second direction D.

The fourth filter cavity T14, the third filter cavity T13 of the second filter branch 13, the fourth filter cavity T24 of the fourth filter branch 15, the third filter cavity T23, the fourth filter cavity T34 of the sixth filter branch 23, the third filter cavity T33, the fourth filter cavity T44 of the eighth filter branch 25, the third filter cavity T43, the fourth filter cavity T54 of the tenth filter branch 33, the third filter cavity T53, the fourth filter cavity T64 of the twelfth filter branch 35, and the third filter cavity T63 are in a row and are sequentially arranged at intervals along the second direction D.

The second filtering cavity T12 of the second filtering branch 13, the second filtering cavity T22 of the fourth filtering branch 15, the second filtering cavity T32 of the sixth filtering branch 23, the second filtering cavity T42 of the eighth filtering branch 25, the second filtering cavity T52 of the tenth filtering branch 33, and the second filtering cavity T62 of the twelfth filtering branch 35 are arranged in a row and sequentially spaced along the second direction D.

The first filter cavity T11 of the second filter branch 13, the first filter cavity T21 of the fourth filter branch 15, the first filter cavity T31 of the sixth filter branch 23, the first filter cavity T41 of the eighth filter branch 25, the first filter cavity T51 of the tenth filter branch 33, and the first filter cavity T61 of the twelfth filter branch 35 are arranged in a row and sequentially spaced along the second direction D.

The housing 11 in this embodiment includes a first cavity, a second cavity, and a third cavity, and four filter branches are provided in each cavity, and the filter branches in each cavity have the same structure. By the mode, the space of the cavity can be fully utilized, the same die is utilized to manufacture the plurality of filtering branches, the plurality of signals can be filtered, and the filtering efficiency is improved.

The present application further provides a communication system, as shown in fig. 9, fig. 9 is a schematic structural diagram of an embodiment of the communication system of the present application. The communication system of the present embodiment includes a terminal 91 and a base station 92, and the terminal 91 communicates with other terminals through the base station 92. The base station 92 includes a base station antenna 921 and a Radio frequency Unit 922(Remote Radio Unit, RRU), the base station antenna 921 is connected to the Radio frequency Unit 922, the Radio frequency Unit 922 includes a filter 10 as shown in the above embodiments, and the filter 10 is configured to filter a Radio frequency signal. Therefore, the bandwidth of the radio frequency signal transmitted by the base station 92 is located at 757Mhz-789Mhz, and the bandwidth of the radio frequency signal received by the base station 92 is located at 702Mhz-734Mhz, so that the design requirement can be met, and the high isolation of the transmitted signal and the received signal can be realized.

In other embodiments, the rf Unit 922 and the base station Antenna 921 may be integrally designed to form an Active Antenna Unit (AAU).

Some embodiments of the present application are filters, which may also be referred to as combiners, i.e., dual-frequency combiners. It is understood that in other embodiments, the duplexer may be referred to as a duplexer.

It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not limiting of the application. In addition, for convenience of description, only a part of structures related to the present application, not all of the structures, are shown in the drawings. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terms "first", "second", etc. in this application are used to distinguish between different objects and not to describe a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims

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

the first filtering branch is arranged on one side of the shell and consists of eight filtering cavities which are sequentially coupled, the eight filtering cavities of the first filtering branch further form four cross-coupling zeros, and the eight filtering cavities of the first filtering branch are divided into two rows arranged along the second direction;

the eight filter cavities of the first filter branch circuit are arranged in a b shape in sequence.

2. The filter of claim 1,

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

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

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

3. The filter of claim 2,

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

and the third filter cavity and the fifth filter cavity of the first filter branch are inductively cross-coupled to form one inductive cross-coupling zero point.

4. The filter of claim 3, wherein the filter comprises:

the second filtering branch consists of eight filtering cavities which are coupled in sequence, and further forms two cross-coupling zeros;

eight filter cavities of the second filter branch circuit are arranged in sequence to form a shape like a Chinese character '9';

the first filtering cavity of the second filtering branch is further respectively adjacent to the first filtering cavity and the eighth filtering cavity of the first filtering branch.

5. The filter of claim 4,

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

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

the second filtering cavities of the second filtering branch are in a row;

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

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

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

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

6. The filter of claim 5,

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

7. The filter of claim 6, wherein the filter comprises:

the third filtering branch circuit has the same structure as the first filtering branch circuit;

the fourth filtering branch consists of eight filtering cavities which are coupled in sequence, and further forms two cross-coupling zeros; eight filter cavities of the fourth filter branch are arranged in sequence to form a shape like a Chinese character '9';

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

and the second filtering cavity to the seventh filtering cavity of the fourth filtering branch circuit and the second filtering cavity to the eighth filtering cavity of the second filtering branch circuit are divided into four rows arranged along the first direction.

8. The filter of claim 7,

the second filter cavities of the second filter branch and the fourth filter cavities of the fourth filter branch are in a row and are arranged at intervals along the second direction;

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

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

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

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

9. The filter of claim 8,

the shell at least comprises a first cavity and a second cavity, the first cavity is provided with the first filtering branch to the fourth filtering branch, and the second cavity is provided with the fifth filtering branch to the eighth filtering branch;

the first filtering branch and the fifth filtering branch have the same structure, the second filtering branch and the sixth filtering branch have the same structure, the third filtering branch and the seventh filtering branch have the same structure, and the fourth filtering branch and the eighth filtering branch have the same structure.

10. A communication system, comprising a terminal and a base station, wherein the terminal communicates with other terminals via the base station; the base station comprises a base station antenna and a radio frequency unit, the base station antenna being connected to the radio frequency unit, the radio frequency unit comprising the filter of any of the preceding claims 1-9, the filter being configured to filter radio frequency signals.