CN113708034A - Filter and communication equipment - Google Patents

Abstract

The application discloses a filter and communication equipment. The filter includes: a housing; the emission filtering branch is coupled with the common cavity and consists of eight emission filtering cavities which are sequentially coupled; the transmitting and filtering branch is arranged on the shell and consists of eight transmitting and filtering cavities which are sequentially coupled; the fifth emission filter cavity and the seventh emission filter cavity of the emission filter branch circuit are in capacitive cross coupling; the fifth emission filter cavity and the eighth emission filter cavity of the emission filter branch circuit are inductively cross-coupled; the bandwidth range of the transmitting and filtering branch circuit is 935MHz-960 MHz; the receiving filter branch is coupled with the common cavity and consists of nine receiving filter cavities which are sequentially coupled; capacitive cross coupling is respectively carried out between a fourth receiving filter cavity and a sixth receiving filter cavity, between the sixth receiving filter cavity and a ninth receiving filter cavity and between a seventh receiving filter cavity and the ninth receiving filter cavity of the receiving filter branch circuit; the bandwidth range of the receiving filtering branch circuit is 890MHz-915 MHz. In this way, the stop-band rejection performance of the filter can be improved.

Description

Filter and communication equipment

Technical Field

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

Background

The cavity filter is a key device of a modern mobile communication system and is widely applied to wireless communication base stations and various communication terminals; the cavity filter is composed of a radio frequency connector, a cavity, a cover plate, a plurality of resonator units and a frequency tuning and coupling strength adjusting component, wherein the resonant frequencies of the plurality of resonator units are distributed in the passband range, and the cavity filter has a blocking function on signals outside the resonant frequencies, so that the function of selecting microwave transmission signals is realized; the cavity filter has the advantages of reliable structure, wide filtering frequency band, parasitic pass band far away from a channel, high Q value, stable electrical property, good heat dissipation performance and the like.

The inventor of the application finds that the arrangement of a plurality of filter cavities in the existing cavity filter is complex and irregular, the size of the filter is increased, and the stop band inhibition performance of the cavity filter is poor.

Disclosure of Invention

The application provides a filter and communication equipment, so as to improve stop band suppression performance of the filter.

In order to solve the technical problem, the application adopts a technical scheme that: providing a filter comprising a housing; a common chamber disposed on the housing; the emission filtering branch is coupled with the common cavity and consists of eight emission filtering cavities which are sequentially coupled; the fifth emission filter cavity and the seventh emission filter cavity of the emission filter branch circuit are in capacitive cross coupling; the fifth emission filter cavity and the eighth emission filter cavity of the emission filter branch circuit are inductively cross-coupled; the bandwidth range of the transmitting and filtering branch circuit is 935MHz-960 MHz; the receiving filter branch is coupled with the common cavity and consists of nine receiving filter cavities which are sequentially coupled; capacitive cross coupling is respectively carried out between a fourth receiving filter cavity and a sixth receiving filter cavity, between the sixth receiving filter cavity and a ninth receiving filter cavity and between a seventh receiving filter cavity and the ninth receiving filter cavity of the receiving filter branch circuit; the bandwidth range of the receiving filtering branch circuit is 890MHz-915 MHz.

Optionally, the eight emission filter cavities and the common cavity of the emission filter branch are divided into three rows arranged along the second direction, and the first direction and the second direction are perpendicular to each other; the sixth emission filtering cavity, the fifth emission filtering cavity and the fourth emission filtering cavity of the emission filtering branch are in a row and are sequentially arranged along the first direction; a seventh emission filtering cavity, an eighth emission filtering cavity, a second emission filtering cavity, a first emission filtering cavity and a common cavity of the emission filtering branch are in a row and are sequentially arranged along a first direction, and the first emission filtering cavity is coupled with the common cavity; an included angle between a connecting line of the center of the third emission filter cavity and the center of the second emission filter cavity of the emission filter branch and a connecting line of the center of the second emission filter cavity and the center of the first emission filter cavity is an obtuse angle; and the fourth emission filtering cavity, the third emission filtering cavity and the second emission filtering cavity of the emission filtering branch circuit are linearly arranged. The eight emission filter cavities and the common cavity are divided into three rows which are sequentially arranged along the second direction, so that the eight emission filter cavities are regularly arranged, the size of the emission filter branch is reduced, and the size of the filter is reduced.

Optionally, eight emission filtering cavities of the emission filtering branch are sequentially window-coupled; a first fly rod is arranged between a fifth emission filter cavity and a seventh emission filter cavity of the emission filter branch circuit; the first flying bar comprises a first coupling part, a second coupling part and a first connecting part, and two ends of the first connecting part are connected with the first coupling part and the second coupling part respectively. The cost of the filter is reduced by pure window coupling between two adjacent filter cavities on the coupling path of the transmitting filter branch; and the first flying rod can realize the capacitive cross coupling between the fifth emission filter cavity and the seventh emission filter cavity of the emission filter branch circuit, and the first flying rod can simplify the structure so as to facilitate the processing and the manufacturing.

Optionally, each emission filter cavity is provided with a first mounting post, a first resonance rod and a first tuning rod; the first resonance rod comprises a first U-shaped side wall and a first hollow inner cavity formed by the first U-shaped side wall; one end of the first tuning rod is arranged in the first hollow inner cavity; the two ends of the first U-shaped side wall bend and extend in the direction departing from the first hollow inner cavity so as to form first disc-shaped structures at the two ends of the first U-shaped side wall, and the first disc-shaped structures are arranged in parallel with the bottom of the first U-shaped side wall; the first U-shaped side wall is fixed to the first mounting post. The first resonant rod is securable to the housing by a first mounting post and the resonant frequency of the first resonant cavity is adjustable by adjusting the depth of the first tuning rod within the first hollow cavity.

Optionally, the receiving filtering branches and the common cavity are divided into four columns arranged along the second direction; a first receiving filter cavity, a second receiving filter cavity, a third receiving filter cavity, a sixth receiving filter cavity and a seventh receiving filter cavity of the receiving filter branch are in a row and are sequentially arranged along a first direction, and the first receiving filter cavity is coupled with a common cavity; an included angle between a connecting line of the center of the third receiving filter cavity and the center of the second receiving filter cavity and a connecting line of the center of the fourth receiving filter cavity and the center of the third receiving filter cavity is an obtuse angle; a projection of the center of the fourth receiving filter cavity in the first direction is located between a projection of the center of the third receiving filter cavity in the first direction and a projection of the center of the fifth receiving filter cavity in the first direction, and a projection of the center of the third receiving filter cavity in the second direction is located between a projection of the center of the fourth receiving filter cavity in the second direction and a projection of the center of the fifth receiving filter cavity in the second direction; the ninth receiving filter cavity and the eighth receiving filter cavity of the receiving filter branch are in a row and are sequentially arranged along the first direction. The receiving filter branch is divided into four rows which are sequentially arranged along the second direction, so that the nine receiving filter cavities are regularly arranged, the size of the receiving filter branch is reduced, and the size of the filter is reduced.

Optionally, second flying bars are respectively arranged between a fourth receiving filter cavity and a sixth receiving filter cavity of the receiving filter branch, between the sixth receiving filter cavity and a ninth receiving filter cavity, and between a seventh receiving filter cavity and the ninth receiving filter cavity; the second flying rod comprises a third coupling part, a fourth coupling part and a second connecting part, and two ends of the second connecting part are connected with the third coupling part and the fourth coupling part respectively. The second flying rod can realize the capacitive cross coupling between the fourth receiving filter cavity and the sixth receiving filter cavity, between the sixth receiving filter cavity and the ninth receiving filter cavity, and between the seventh receiving filter cavity and the ninth receiving filter cavity of the receiving filter branch, and the second flying rod can simplify the structure for processing and manufacturing.

Optionally, nine receiving filter cavities of the receiving filter branch are window-coupled in sequence. And the cost of the filter is reduced by pure window coupling between two adjacent filter cavities on the coupling path of the receiving filter branch.

Optionally, each receiving filter cavity is provided with a second mounting post, a second resonance rod and a second tuning rod; the second resonance rod comprises a second U-shaped side wall and a second hollow inner cavity formed by the second U-shaped side wall; one end of the second tuning rod is arranged in the second hollow inner cavity; the two ends of the second U-shaped side wall bend and extend in the direction departing from the second hollow inner cavity so as to form second disc-shaped structures at the two ends of the second U-shaped side wall, and the second disc-shaped structures are arranged in parallel with the bottom of the second U-shaped side wall; the second U-shaped side wall is fixed to the second mounting post. The second resonant rod may be secured to the housing by a second mounting post, and the resonant frequency of the second resonant cavity may be adjusted by adjusting the depth of the second tuning rod within the second hollow cavity.

Optionally, a first port connected to the common lumen;

the second port is connected with the eighth transmitting filter cavity of the transmitting filter branch circuit;

and the third port is connected with the ninth receiving filter cavity of the receiving filter branch circuit.

The transmitting filtering branch and the receiving filtering branch share the first port, so that the cost can be saved, and the size of the filter can be reduced.

In order to solve the above technical problem, the present application adopts another technical solution: a communication device is provided. The communication equipment comprises an antenna and a radio frequency unit connected with the antenna, wherein the radio frequency unit comprises the filter and is used for filtering radio frequency signals.

The beneficial effect of this application is: different from the prior art, capacitive cross coupling is performed between the fifth emission filter cavity and the seventh emission filter cavity of the emission filter branch circuit in the embodiment of the present application, so that low-end rejection of the bandwidth of the emission filter branch circuit can be well controlled, and better low-end rejection of the bandwidth can be obtained; inductive cross coupling is carried out between a fifth transmitting filter cavity and an eighth transmitting filter cavity of the transmitting filter branch, high-end rejection of the bandwidth of the transmitting filter branch can be well controlled, so that good high-end rejection of the bandwidth can be obtained, capacitive cross coupling is respectively carried out between a fourth receiving filter cavity and a sixth receiving filter cavity, between a sixth receiving filter cavity and a ninth receiving filter cavity, and between a seventh receiving filter cavity and a ninth receiving filter cavity of the receiving filter branch, so that high-end rejection of the bandwidth of the receiving filter branch can be well controlled, good high-end rejection of the bandwidth can be obtained, low-end rejection of the bandwidth of the receiving filter branch can be well controlled, good low-end rejection of the bandwidth can be obtained, and therefore stop band rejection performance of the filter can be improved; in addition, the bandwidth range of the transmitting and filtering branch circuit is 935MHz-960MHz, and the bandwidth of the transmitting and filtering branch circuit can be accurately controlled; the bandwidth range of the receiving filter branch is 890MHz-915MHz, and the bandwidth of the receiving filter branch can be accurately controlled.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic diagram of the structure of the transmitting filter branch of the filter of the present application;

FIG. 2 is a schematic diagram of the topology of the transmit filter branch of the embodiment of FIG. 1;

FIG. 3 is a schematic structural diagram of a first tuning rod, a first resonant rod and a first mounting post assembly of the launch filter cavity of the embodiment of FIG. 1;

FIG. 4 is a schematic structural diagram of a combined structure of a first flying bar and a first support clamping seat in the transmitting filter branch of the embodiment of FIG. 1;

FIG. 5 is a schematic diagram of the structure of the receiving filter branch of the filter of the present application;

FIG. 6 is a schematic diagram of the topology of the receiving filter branch of the embodiment of FIG. 5;

FIG. 7 is a schematic diagram of an equivalent circuit structure in which a transmitting filter branch and a receiving filter branch are combined to form a filter;

FIG. 8 is a diagram illustrating a simulation structure of a filter formed by combining a transmitting filter branch and a receiving filter branch;

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

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. 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" and "second" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise. 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.

First, a filter is proposed, please refer to fig. 1 and fig. 2, in which fig. 1 is a schematic structural diagram of a transmitting filter branch of the filter of the present application, and fig. 2 is a schematic structural diagram of the transmitting filter branch of the embodiment of fig. 1. The filter 10 of the present embodiment includes a housing 11, a common cavity C, and a transmitting filter branch 12. And the common cavity C is arranged on the shell 11, and the transmitting and filtering branch 12 is coupled with the common cavity C and consists of eight transmitting and filtering cavities which are sequentially coupled.

Specifically, the eight emission filter cavities of the emission filter branch 12 include a first emission filter cavity a1, a second emission filter cavity a2, a third emission filter cavity A3, a fourth emission filter cavity a4, a fifth emission filter cavity a5, a sixth emission filter cavity a6, a seventh emission filter cavity a7, and an eighth emission filter cavity A8; capacitive cross coupling is provided between the fifth emission filter cavity a5 and the seventh emission filter cavity a7 of the emission filter branch 12; the fifth emission filter cavity a5 and the eighth emission filter cavity A8 of the emission filter branch circuit 12 are inductively cross-coupled; the bandwidth range of the transmitting and filtering branch 12 is 935MHz-960 MHz.

It can be seen that capacitive cross coupling between the fifth emission filter cavity a5 and the seventh emission filter cavity a7 of the emission filter branch 12 can well control the low-end rejection of the bandwidth of the emission filter branch, so as to obtain better low-end rejection of the bandwidth; the inductive cross coupling between the fifth emission filter cavity a5 and the eighth emission filter cavity A8 of the emission filter branch 12 can well control the high-end rejection of the bandwidth of the emission filter branch to obtain better high-end rejection of the bandwidth, so that the stop-band rejection performance of the filter 10 can be improved; in addition, the bandwidth of the transmitting and filtering branch 12 ranges from 935MHz to 960MHz, and the bandwidth of the transmitting and filtering branch 12 can be accurately controlled.

Optionally, as shown in fig. 1, the eight emission filter cavities and the common cavity C of the emission filter branch 12 are divided into three rows arranged along the second direction y, and the first direction x and the second direction y are arranged perpendicular to each other; the sixth emission filter cavity a6, the fifth emission filter cavity a5 and the fourth emission filter cavity a4 of the emission filter branch 12 are in a row and are sequentially arranged along the first direction x; the seventh emission filter cavity a7, the eighth emission filter cavity A8, the second emission filter cavity a2, the first emission filter cavity a1 and the common cavity C of the emission filter branch 12 are in a row and are sequentially arranged along the first direction x; the first emission filter cavity a1 is coupled to the common cavity C; an included angle between a connecting line of the center of the third emission filter cavity A3 and the center of the second emission filter cavity A2 of the emission filter branch 12 and a connecting line of the center of the second emission filter cavity A2 and the center of the first emission filter cavity A1 is an obtuse angle; the fourth emission filter cavity A4, the third emission filter cavity A3 and the second emission filter cavity A2 of the emission filter branch circuit 12 are linearly arranged; and the fifth emission filter cavity a5 is respectively disposed adjacent to the sixth emission filter cavity a6, the seventh emission filter cavity a7, the eighth emission filter cavity A8 and the fourth emission filter cavity a 4.

It can be seen that the eight emission filter cavities and the common cavity C are divided into three rows arranged in sequence along the second direction y, so that the eight emission filter cavities are regularly arranged, and thus the volume of the emission filter branch 12 is reduced, and the volume of the filter 10 is reduced.

Optionally, as shown in fig. 1, eight emission filter cavities of the emission filter branch 12 are sequentially window-coupled, that is, a first emission filter cavity a1 is window-coupled to a second emission filter cavity a2, a second emission filter cavity a2 is window-coupled to a third emission filter cavity A3, a third emission filter cavity A3 is window-coupled to a fourth emission filter cavity a4, a fourth emission filter cavity a4 is window-coupled to a fifth emission filter cavity a5, a fifth emission filter cavity a5 is window-coupled to a sixth emission filter cavity A6, a sixth emission filter cavity A6 is window-coupled to a seventh emission filter cavity a7, and a seventh emission filter cavity a7 is window-coupled to an eighth emission filter cavity A8.

Therefore, the two adjacent filter cavities on the coupling path of the transmitting filter branch 12 are coupled by pure windows, so that the cost of the filter 10 can be reduced.

Referring to fig. 3, fig. 3 is a schematic structural diagram of a combination structure of a first tuning rod, a first resonant rod and a first mounting post of the transmission filter cavity in fig. 1. As shown in fig. 1 and 3, each emission filter cavity is provided with a first mounting post 40, a first resonant rod 20, and a first tuning rod 30. Wherein, the first resonant rod 20 comprises a first U-shaped sidewall 210 and a first hollow inner cavity 220 formed by the first U-shaped sidewall 210; one end of the first tuning rod 30 is disposed within the first hollow interior 220 and the resonant frequency of the first resonant cavity can be adjusted by adjusting the depth of the first tuning rod 30 within the first hollow interior 220. The two ends of the first U-shaped sidewall 210 are bent and extended in a direction away from the first hollow cavity 220, so as to form a first disc-shaped structure 230 at the two ends of the first U-shaped sidewall 210, and the first disc-shaped structure 230 is parallel to the bottom of the first U-shaped sidewall 210. The first U-shaped sidewall 210 is fixed to the first mounting post 40, as shown in fig. 3, the first U-shaped sidewall 210 is fixed to the first mounting post 40, and the first resonant rod 20 is fixed to the housing 11 through the first mounting post 40. In this embodiment, the first resonant rod 20, the first hollow cavity 220 and the first tuning rod 30 are coaxially disposed.

Further, a mounting hole (not shown) may be provided on the bottom of the first U-shaped sidewall 210, one end of the first mounting post 40 is fixed on the housing 11, and the other end of the first mounting post 40 is mounted in the mounting hole, so as to fix the first resonant rod 20 on the first mounting post 40; the mounting holes may be through holes, the mounting holes may be threaded holes, and the first mounting post 40 is a stud. In other embodiments, the mounting hole may also be a blind hole.

Alternatively, the transmitting filter cavity of the present embodiment may be a metal filter cavity, and the first resonant rod 20 may be a metal resonant rod.

The material of the first resonant rod 20 of the present embodiment may be the cut 1215 MS. Of course, in other embodiments, the first resonant rod 20 may also be an M8 or M4 screw rod, and the like, and is made of copper or silver.

The eight emission filter cavities of the emission filter branch 12 have the same size, so that the production is convenient, and the cost is saved. The radii of the eight emission filter cavities may be less than 21mm, e.g., 20mm, 19mm, 18mm, etc.

It can be seen that the first resonant rod 20 can be fixed to the housing 11 by the first mounting post 40, and the resonant frequency of the first resonant cavity can be adjusted by adjusting the depth of the first tuning rod 30 within the first hollow interior 220.

Referring to fig. 4, fig. 4 is a schematic structural diagram of a combined structure of a first flying bar and a first supporting clamping seat in the transmitting filter branch of the embodiment of fig. 1. The first flying bar 60 is disposed between the fifth emission filter cavity a5 and the seventh emission filter cavity a7 of the emission filter branch 12 so that the fifth emission filter cavity a5 and the seventh emission filter cavity a7 are capacitively cross-coupled. The first flying rod 60 can realize the capacitive cross coupling between the fifth emission filter cavity a5 and the seventh emission filter cavity a7 of the emission filter branch 12, and the first flying rod 60 can be arranged into a sheet-shaped flying rod, so that the structure is simple, the processing and the manufacturing are convenient, the production cost is reduced, and the realizability of the scheme is improved.

Specifically, the first flying bar 60 includes a first coupling portion 610, a second coupling portion 620 and a first connecting portion 630, two ends of the first connecting portion 630 are respectively connected with the first coupling portion 610 and the second coupling portion 620, and the first coupling portion 610 and the second coupling portion 620 are located on the same side of the first connecting portion 630. The first coupling portion 610, the first connecting portion 630, and the second coupling portion 620 are sequentially connected to form a first flying bar 60; the first coupling part 610 is coupled with the first resonance rod 20 in the fifth emission filter cavity a5 to form a coupling capacitance therebetween, and the second coupling part 620 is coupled with the first resonance rod 20 in the seventh emission filter cavity a7 to form a coupling capacitance therebetween.

As shown in fig. 4, the filter 10 further includes: the support socket 70 may be disposed on the housing 11, and the support socket 70 is provided with a through hole (not shown), wherein the first connecting portion 630 penetrates through the through hole, and the support socket 70 may fix the first flying bar 60.

The first flying bar 60 of the present embodiment may be implemented by a metal probe, and the support socket 70 may be implemented by PTFE or engineering plastic.

As shown in fig. 2, specifically, the fifth emission filter cavity a5 and the seventh emission filter cavity a7 are capacitively cross-coupled to form a capacitive cross-coupling zero C₁The fifth emission filter cavity A5 and the eighth emission filter cavity A8 are inductively cross-coupled to form an inductive cross-coupling zero point L₁To form two cross-coupled zeros of the transmit filter branch 12. The cross coupling zero point is also called a transmission zero point, and the transmission zero point is a transmission function equal to zero, namely, the electromagnetic energy cannot pass through the network at the frequency point corresponding to the transmission zero point, so that the complete isolation effect is achieved, the suppression effect on signals outside a passband is achieved, and the high isolation among a plurality of passbands can be better achieved.

Wherein, an adjusting screw 80 is arranged between the fifth emission filter cavity A5 and the eighth emission filter cavity A8 of the emission filter branch 12; first metal coupling ribs 81 are arranged between the seventh emission filter cavity A7 and the eighth emission filter cavity A8 of the emission filter branch 12 and between the common cavity C and the first emission filter cavity A1 of the emission filter branch 12.

Therefore, by providing an adjusting screw 80 between the fifth emission filter chamber a5 and the eighth emission filter chamber A8 of the emission filter branch 12; inductive cross-coupling between the fifth emission filter cavity a5 and the eighth emission filter cavity A8 of the emission filter branch 12 can be achieved; and the coupling strength between the seventh emission filter cavity a7 and the eighth emission filter cavity A8, and between the common cavity C of the emission filter branch 12 and the first emission filter cavity a1 on the coupling path of the emission filter branch 12 can be improved through the first metal coupling rib 81, so that the loss of energy is reduced, and the quality of energy transmission is improved.

Further, the filter 10 further includes a cover plate (not shown) covering the eight emission filter cavities, and the other end of the first tuning rod 30 is disposed on the cover plate, wherein the first tuning rod 30 may be a metal screw.

Referring to fig. 5 and fig. 6, fig. 5 is a schematic diagram of a receiving filter branch of a filter according to the present application, and fig. 6 is a schematic diagram of a topology structure of the receiving filter branch in the embodiment of fig. 5. The filter 10 further includes a receiving filter branch 13 disposed on the housing 11 and composed of nine receiving filter cavities coupled in sequence.

Specifically, the nine receiving filter cavities of the receiving filter branch 13 include a first receiving filter cavity B1, a second receiving filter cavity B2, a third receiving filter cavity B3, a fourth receiving filter cavity B4, a fifth receiving filter cavity B5, a sixth receiving filter cavity B6, a seventh receiving filter cavity B7, an eighth receiving filter cavity B8, and a ninth receiving filter cavity B9.

Capacitive cross coupling is respectively carried out between the fourth receiving filter cavity B4 and the sixth receiving filter cavity B6, between the sixth receiving filter cavity B6 and the ninth receiving filter cavity B9, and between the seventh receiving filter cavity B7 and the ninth receiving filter cavity B9 of the receiving filter branch 13, wherein the bandwidth range of the receiving filter branch 13 is 890MHz-915 MHz.

Specifically, as shown in fig. 6, the fourth receiving filter cavity B4 and the sixth receiving filter cavity B6 of the receiving filter branch 13 are capacitively cross-coupled to form a capacitive cross-coupling zero C₂A sixth receiving filter cavity B6 and a ninth receiving filter cavity B9 are capacitively cross-coupled to form a capacitive cross-coupling zero C₃And the seventh receiving filter cavity B7 and the ninth receiving filter cavity B9 are capacitively cross-coupled to form a capacitive cross-coupling zero point C₄To form three capacitive cross-coupling zeros of the receive filter branch 13.

It can be seen that, capacitive cross coupling is respectively performed between the fourth receiving filter cavity B4 and the sixth receiving filter cavity B6, between the sixth receiving filter cavity B6 and the ninth receiving filter cavity B9, and between the seventh receiving filter cavity B7 and the ninth receiving filter cavity B9 of the receiving filter branch 13, so that high-end rejection of the bandwidth of the receiving filter branch can be well controlled to obtain better high-end rejection of the bandwidth, and low-end rejection of the bandwidth of the receiving filter branch can be well controlled to obtain better low-end rejection of the bandwidth, and therefore, stop-band rejection performance of the filter 10 can be improved; in addition, the bandwidth of the receiving filter branch circuit 13 ranges from 890MHz to 915MHz, and the bandwidth of the receiving filter branch circuit 13 can be accurately controlled.

Wherein the receiving filtering branches 13 and the common cavity C are divided into four columns arranged along the second direction y; the first receiving filter cavity B1, the second receiving filter cavity B2, the third receiving filter cavity B3, the sixth receiving filter cavity B6 and the seventh receiving filter cavity B7 of the receiving filter branch 13 are in a row and are sequentially arranged along the first direction x, and the first receiving filter cavity B1 is coupled with the common cavity C; an included angle between a connecting line of the center of the third receiving filter cavity B3 and the center of the second receiving filter cavity B2 and a connecting line of the center of the fourth receiving filter cavity B4 and the center of the third receiving filter cavity B3 is an obtuse angle; the projection of the centre of the fourth receiving filter cavity B4 in the first direction x is located between the projection of the centre of the third receiving filter cavity B3 in the first direction x and the projection of the centre of the fifth receiving filter cavity B5 in the first direction x, the projection of the centre of the third receiving filter cavity B3 in the second direction y is located between the projection of the centre of the fourth receiving filter cavity B4 in the second direction y and the projection of the centre of the fifth receiving filter cavity B5 in the second direction y; the ninth receiving filter cavity B9 and the eighth receiving filter cavity B8 of the receiving filter branch 13 are in a row and are sequentially arranged along the first direction x; and the sixth receiving filter cavity B6 is disposed adjacent to the fourth receiving filter cavity B4, the fifth receiving filter cavity B5, the ninth receiving filter cavity B9 and the seventh receiving filter cavity B7, respectively.

As can be seen, the receiving filter branch 13 and the common cavity C are divided into four rows arranged in sequence along the second direction y, so that the nine receiving filter cavities are regularly arranged, and thus the volume of the receiving filter branch 13 is reduced, and the volume of the filter 10 is reduced.

Nine receiving filter cavities of the receiving filter branch 13 are sequentially coupled in a window mode, that is, a first receiving filter cavity B1 is coupled with a second receiving filter cavity B2 in a window mode, a second receiving filter cavity B2 is coupled with a third receiving filter cavity B3 in a window mode, a third receiving filter cavity B3 is coupled with a fourth receiving filter cavity B4 in a window mode, a fourth receiving filter cavity B4 is coupled with a fifth receiving filter cavity B5 in a window mode, a fifth receiving filter cavity B5 is coupled with a sixth receiving filter cavity B6 in a window mode, a sixth receiving filter cavity B6 is coupled with a seventh receiving filter cavity B7 in a window mode, a seventh receiving filter cavity B7 is coupled with an eighth receiving filter cavity B8 in a window mode, and an eighth receiving filter cavity B8 is coupled with a ninth receiving filter cavity B9 in a window mode.

The cost of the filter 10 is reduced by pure window coupling between two adjacent filter cavities on the coupling path of the receiving filter branch 13.

In addition, second metal coupling ribs 82 are respectively arranged between the seventh receiving filter cavity B7 and the eighth receiving filter cavity B8, between the eighth receiving filter cavity B8 and the ninth receiving filter cavity B9, and between the common cavity C and the first receiving filter cavity B1 of the receiving filter branch 13.

Therefore, the coupling strength between the seventh receiving filter cavity B7 and the eighth receiving filter cavity B8, between the eighth receiving filter cavity B8 and the ninth receiving filter cavity B9, and between the common cavity C and the first receiving filter cavity B1 on the coupling path of the receiving filter branch 13 can be improved by the second metal coupling rib 82, so that the loss of energy is reduced, and the quality of energy transmission is improved.

Each receiving filter cavity is provided with a second mounting post, a second resonant rod 21 and a second tuning rod 31; a second resonant rod 21 including a second U-shaped sidewall and a second hollow cavity formed by the second U-shaped sidewall; a second tuning rod 31, one end of the second tuning rod 31 is arranged in the second hollow inner cavity; the two ends of the second U-shaped side wall bend and extend in the direction departing from the second hollow inner cavity so as to form second disc-shaped structures at the two ends of the second U-shaped side wall, and the second disc-shaped structures are arranged in parallel with the bottom of the second U-shaped side wall; the second U-shaped side wall is fixed to the second mounting post.

The schematic structural diagram of the combined structure of the second tuning rod 31, the second resonant rod 21 and the second mounting post of the receiving filtering branch 13 is similar to the schematic structural diagram of the combined structure of the first tuning rod 30, the first resonant rod 20 and the first mounting post 40 of the transmitting filtering branch 12, as shown in fig. 3, and is not repeated herein.

Thus, the second resonant rod 21 is fixed to the housing 11 by the second mounting post, and the resonant frequency of the second resonant cavity can be adjusted by adjusting the depth of the second tuning rod 31 within the second hollow cavity.

Nine receiving filter cavities of the receiving filter branch circuit 13 can be the same in size, so that the production is convenient, and the cost is saved. The radius of the nine receiving filter cavities may be less than 21mm, e.g. 20mm, 19mm, 18mm, etc.

Eight transmission filtering chambeies or nine receipt filtering chambeies all can be realized by metal chamber, metal resonance pole and tuning screw combination, in order to satisfy frequency and power requirement, the resonance pole of receiving and dispatching channel all adopts the structure of taking the tilting disk, satisfies under the temperature drift index prerequisite, and the resonance pole material of transmission filtering branch road 12 and receipt filtering branch road 13 all chooses the iron material for use, can reduce the manufacturing cost of wave filter 10 to improve the product competitiveness of wave filter 10.

Second flying rods are respectively arranged between the fourth receiving filter cavity B4 and the sixth receiving filter cavity B6, between the sixth receiving filter cavity B6 and the ninth receiving filter cavity B9, and between the seventh receiving filter cavity B7 and the ninth receiving filter cavity B9 of the receiving filter branch circuit 13; the second flying rod comprises a third coupling part, a fourth coupling part and a second connecting part, and two ends of the second connecting part are connected with the third coupling part and the fourth coupling part respectively. The second flying rod can be arranged in a sheet shape, and is simple in structure and convenient to process and manufacture.

Specifically, the schematic structure diagram of the combined structure of the second flying bar, the third coupling portion, the fourth coupling portion and the second connecting portion of the receiving filtering branch 13 is similar to the schematic structure diagram of the combined structure of the first flying bar, the first coupling portion, the second coupling portion and the first connecting portion of the transmitting filtering branch 12, as shown in fig. 4, and is not repeated here.

Referring to fig. 7, fig. 7 is a schematic diagram of an equivalent circuit structure of a filter formed by combining a transmitting filter branch and a receiving filter branch, as shown in fig. 7, an impedance Z0 at an input port is about 50 ohms, an impedance regulator ZV0 is disposed between an impedance Z0 and a first transmitting filter cavity a1, and an impedance Z1 at an output port of the transmitting filter branch 12 is about 50 ohms; in order to ensure that electromagnetic signals are transmitted between the eight emission filter cavities of the emission filter branch 12, impedance regulators ZV1 are required to be respectively arranged between the input port and the first emission filter cavity a1, between adjacent filter cavities on the coupling path, between non-cascaded filter cavities forming cross coupling, and between the eighth emission filter cavity A8 and the output port, so as to realize impedance matching; and the impedance Z2 at the output port of the receiving filtering branch 13 is about 50 ohms; in order to ensure that electromagnetic signals are transmitted between the nine emission filter cavities of the receiving filter branch 13, impedance adjusters ZV2 are respectively disposed between the input port and the first receiving filter cavity B1, between adjacent filter cavities on the coupling path, between non-cascaded filter cavities forming cross coupling, and between the ninth receiving filter cavity B9 and the output port, so as to implement impedance matching.

Fig. 8 is a schematic diagram of a simulation structure of a filter formed by combining a transmitting filtering branch and a receiving filtering branch, and as can be seen from fig. 8, through experimental tests, a frequency band curve S1 represents a simulation curve of the transmitting filtering branch 12, and a frequency band curve S2 represents a simulation curve of the receiving filtering branch 13; as shown in the frequency band curve S1, there are a low-end coupling zero point a and a high-end coupling zero point b. As shown in the frequency band curve S2, there is one low-side coupling zero c and two high-side coupling zeros d, e. The suppression of the emission filtering branch 12 at the frequency point 921.0MHz (m15) is-27.303 dB, the suppression at the frequency point 885.0MHz (m16) is-43.000 dB, the suppression at the frequency point 890.0MHz (m17) is-1.489 dB, the suppression at the frequency point 915.0MHz (m18) is-1.406 dB, the suppression at the frequency point 860.0MHz (m19) is-82.667 dB, the suppression at the frequency point 925.0MHz (m20) is-50.149 dB, and the suppression at the frequency point 935.0MHz (m27) is-86.521 dB, so that the emission filtering branch 12 can meet the design requirement of out-of-band suppression.

The suppression of the receiving filtering branch 13 at the frequency point 915.0MHz (m21) is-124.547 dB, the suppression at the frequency point 970.0MHz (m22) is-32.043 dB, the suppression at the frequency point 965.0MHz (m23) is-14.728 dB, the suppression at the frequency point 930.0MHz (m24) is-20.024 dB, the suppression at the frequency point 935.0MHz (m25) is-1.162 dB, and the suppression at the frequency point 960.0MHz (m26) is-0.978 dB, so that the receiving filtering branch 13 can meet the design requirement of out-of-band suppression.

When the temperature range is-40-90 ℃, the filter is applied outdoors, the in-band ripple of the transmitting and filtering branch circuit 12 is less than 1dB, the average insertion loss between 892.5-897.5MHz is less than 1.35dB, the maximum insertion loss is less than 1.6dB, and the return loss at the ANT/TRX position is more than 16 dB; wherein the suppression at 0.9-820MHz is greater than 100dB, the suppression at 820-855MHz is greater than 110dB, the suppression at 855-880MHz is greater than 100dB, the suppression at 880-915MHz is greater than 105dB, the suppression at 915-925 MHz is greater than 27dB, the suppression at 925-930MHz is greater than 6dB, the suppression at 970-1025MHz is greater than 25dB, the suppression at 1025MHz is greater than 55dB, the suppression at 1400-1850MHz is greater than 65dB, the suppression at 1850-1920 0MHz is greater than 100dB, the suppression at 2700MHz is greater than 65dB, the suppression at 2700-2900MHz is greater than 90dB, the suppression at 2900-3300MHz is greater than 30dB, the suppression at 3300-3700MHz is greater than 61dB, the suppression at 3800MHz is greater than 78dB, the suppression at 37040 MHz is greater than 35dB, the suppression at 4625-4800MHz was greater than 35dB, the suppression at 5150-5350MHz was greater than 61dB, the suppression at 5550-5725MHz was greater than 25dB, the suppression at 5725-5850MHz was greater than 61dB, the suppression at 6475-6720MHz was greater than 25dB, and the suppression at 7000-12500MHz was greater than 20 dB.

When the temperature range is-40-90 ℃, the filter is applied outdoors, the in-band ripple of the receiving filter branch circuit 13 is less than 1.2dB, the average insertion loss between 892.5-897.5MHz is less than 1.3dB, the maximum insertion loss is less than 1.9dB, the return loss at the ANT/TRX position is more than 16dB, and the intermodulation product IM3 in the receiving frequency band is less than or equal to-104 dBm; wherein the inhibition at 0.9-640MHz is more than 80dB, the inhibition at 640-825MHz is more than 75dB, the inhibition at 825-860MHz is more than 40dB, the inhibition at 860-880MHz is more than 37dB, the inhibition at 880-885 MHz is more than 37dB, the inhibition at 921-925MHz is more than 20dB, the inhibition at 925-935MHz is more than 32dB, the inhibition at 935-960MHz is more than 80dB, the inhibition at 960-1285MHz is more than 85dB, the inhibition at 1285-2690MHz is more than 70dB, and the inhibition at 2690-3500MHz is more than 40 dB.

In addition, the filter 10 includes a transmitting filter branch 12, a receiving filter branch 13, a first port, a second port, and a third port.

Optionally, the first port is connected to the common cavity C; the second port is connected with the eighth emission filter cavity A8 of the emission filter branch circuit 12; the third port is connected to the ninth receiving filter cavity B9 of the receiving filter branch 13. Therefore, the transmitting filter branch 12 and the receiving filter branch 13 share the first port, which can save cost and reduce the size of the filter 10.

The filter 10 is a microwave filter applied to a 5G mobile communication system, and has the characteristics that the working frequency band of the transmitting filtering branch 12 is 935MHz-960MHz, the working frequency band of the receiving filtering branch 13 is 890MHz-915MHz, the anti-interference capability is strong, the whole volume is small, and the weight is light. And realized the mutual suppression of 105dB between the transmitting filtering branch 12 and the receiving filtering branch 13, the low end of the transmitting filtering branch 12 has adopted 2 transmission zero points, meanwhile because of the requirement of high intermodulation, the combination between the transmitting filtering branch 12 and the receiving filtering branch 13 has adopted the form of common cavity C to realize, in order to satisfy the requirement of low insertion loss, high out-of-band suppression degree of 5G communication application, compact, optimal topological row cavity structure has been used, simultaneously have the advantages such as structural design is simple, low insertion loss, low in-band fluctuation, good uniformity, the production cost has been reduced, do benefit to batch production, raise production efficiency.

The filter 10 in the embodiment of the application has low loss, and can ensure low energy consumption of the communication module; the transmitting and filtering branch of the filter 10 is designed by combining 8-order resonant cavities, the receiving and filtering branch of the filter 10 is designed by combining 9-order resonant cavities, and a coupling zero structure is introduced, so that the high-frequency-resistant filter has high anti-interference capacity and can ensure that a communication system is not interfered by stray signals; the filter 10 is simple in design scheme, low in cost, and good in structure and stable in electrical performance.

The present application further provides a communication device, as shown in fig. 9, fig. 9 is a schematic structural diagram of an embodiment of the communication device of the present application. The communication device of the present embodiment includes an antenna 92 and a radio frequency unit 91 connected to the antenna 92, the radio frequency unit 91 includes a filter 10 as shown in the above-mentioned embodiment, and the filter 10 is used for filtering a radio frequency signal.

In other embodiments, the rf Unit 91 may be integrated with the Antenna 92 to form an Active Antenna Unit (AAU).

Some embodiments of the present application are referred to as filters and 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.

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 (10)

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

a housing;

a common chamber disposed on the housing;

the emission filtering branch is coupled with the common cavity and consists of eight emission filtering cavities which are sequentially coupled; the fifth emission filter cavity and the seventh emission filter cavity of the emission filter branch circuit are in capacitive cross coupling; the fifth emission filter cavity and the eighth emission filter cavity of the emission filter branch circuit are inductively cross-coupled; the bandwidth range of the transmitting and filtering branch circuit is 935MHz-960 MHz;

the receiving filter branch is coupled with the common cavity and consists of nine receiving filter cavities which are sequentially coupled; capacitive cross coupling is respectively formed between a fourth receiving filter cavity and a sixth receiving filter cavity of the receiving filter branch circuit, between the sixth receiving filter cavity and a ninth receiving filter cavity, and between a seventh receiving filter cavity and the ninth receiving filter cavity; the bandwidth range of the receiving filtering branch circuit is 890MHz-915 MHz.

2. The filter of claim 1,

the eight emission filter cavities of the emission filter branch circuit and the common cavity are divided into three rows arranged along a second direction, and the first direction and the second direction are perpendicular to each other;

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

a seventh emission filtering cavity, an eighth emission filtering cavity, a second emission filtering cavity, a first emission filtering cavity and the common cavity of the emission filtering branch are in a row and are sequentially arranged along the first direction, and the first emission filtering cavity is coupled with the common cavity;

an included angle between a connecting line of the center of the third emission filter cavity and the center of the second emission filter cavity of the emission filter branch and a connecting line of the center of the second emission filter cavity and the center of the first emission filter cavity is an obtuse angle;

and the fourth emission filtering cavity, the third emission filtering cavity and the second emission filtering cavity of the emission filtering branch circuit are linearly arranged.

3. The filter of claim 2, wherein eight transmit filter cavities of the transmit filter branch are sequentially window-coupled;

a first fly rod is arranged between a fifth emission filter cavity and a seventh emission filter cavity of the emission filter branch circuit; the first flying bar comprises a first coupling part, a second coupling part and a first connecting part, and two ends of the first connecting part are respectively connected with the first coupling part and the second coupling part.

4. The filter of claim 3,

each emission filter cavity is provided with a first mounting column, a first resonance rod and a first tuning rod;

the first resonance rod comprises a first U-shaped side wall and a first hollow inner cavity formed by the first U-shaped side wall;

the first tuning rod, one end of the first tuning rod is arranged in the first hollow inner cavity;

the two ends of the first U-shaped side wall bend and extend in a direction departing from the first hollow inner cavity so as to form first disc-shaped structures at the two ends of the first U-shaped side wall, and the first disc-shaped structures are arranged in parallel with the bottom of the first U-shaped side wall; the first U-shaped side wall is fixed to the first mounting post.

5. The filter of claim 4,

the receiving filter branches and the common cavity are divided into four columns arranged along the second direction;

a first receiving filter cavity, a second receiving filter cavity, a third receiving filter cavity, a sixth receiving filter cavity and a seventh receiving filter cavity of the receiving filter branch are in a row and are sequentially arranged along the first direction, and the first receiving filter cavity is coupled with the common cavity;

an included angle between a connecting line of the center of the third receiving filter cavity and the center of the second receiving filter cavity and a connecting line of the center of the fourth receiving filter cavity and the center of the third receiving filter cavity is an obtuse angle;

a projection of a center of the fourth receiving filter cavity in the first direction is located between a projection of a center of the third receiving filter cavity in the first direction and a projection of a center of the fifth receiving filter cavity in the first direction, and a projection of a center of the third receiving filter cavity in the second direction is located between a projection of a center of the fourth receiving filter cavity in the second direction and a projection of a center of the fifth receiving filter cavity in the second direction;

and the ninth receiving filter cavity and the eighth receiving filter cavity of the receiving filter branch are in a row and are sequentially arranged along the first direction.

6. The filter of claim 5,

second flying rods are respectively arranged between a fourth receiving filter cavity and a sixth receiving filter cavity of the receiving filter branch, between the sixth receiving filter cavity and a ninth receiving filter cavity, and between a seventh receiving filter cavity and the ninth receiving filter cavity; the second flying bar comprises a third coupling part, a fourth coupling part and a second connecting part, and two ends of the second connecting part are respectively connected with the third coupling part and the fourth coupling part.

7. The filter of claim 6, wherein nine receive filter cavities of the receive filter branches are window-sequentially coupled.

8. The filter of claim 7,

each receiving filter cavity is provided with a second mounting column, a second resonance rod and a second tuning rod; the second resonance rod comprises a second U-shaped side wall and a second hollow inner cavity formed by the second U-shaped side wall;

the second tuning rod, one end of the second tuning rod is arranged in the second hollow inner cavity;

the two ends of the second U-shaped side wall bend and extend in the direction departing from the second hollow inner cavity so as to form second disc-shaped structures at the two ends of the second U-shaped side wall, and the second disc-shaped structures are arranged in parallel with the bottom of the second U-shaped side wall; the second U-shaped side wall is fixed to the second mounting post.

9. The filter of claim 8, further comprising:

a first port connected to the common chamber;

the second port is connected with the eighth transmitting filter cavity of the transmitting filter branch circuit;

and the third port is connected with a ninth receiving filter cavity of the receiving filter branch circuit.

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 a radio frequency signal.

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