Cavity filter

Abstract

The present application relates to the technical field of communications. Disclosed is a cavity filter. The cavity filter comprises a cavity body and a cover plate; the cavity body comprises a bottom wall and an open end, the cover plate covering the open end, and the cover plate being arranged opposite the bottom wall; a plurality of filtering assemblies are provided in the cavity body, the plurality of filtering assemblies being respectively used for screening signals of different frequency bands; each filtering assembly comprises one or more resonant units, each resonant unit comprising a resonant cavity and a resonator provided in the resonant cavity, and adjacent resonant units in the filtering assembly being coupled to each other; one or more communication windows are provided between two adjacent filtering assemblies, the communication window communicating one resonant cavity in one filtering assembly with one resonant cavity in the other filtering assembly, and the communication window extending from the open end to the bottom wall. The present application can implement the design for reducing insertion loss and reducing frequency of cavity filters without increasing the size of cavity filters, and improves the power capacity of cavity filters.

Description

A cavity filter

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411999846.0, filed with the State Intellectual Property Office of the People's Republic of China on December 31, 2024, entitled "A Cavity Filter", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a cavity filter. Background Technology

[0004] Cavity filters offer excellent frequency-selective filtering capabilities in circuits and high-frequency electronic systems. They suppress unwanted signals and noise outside their designated frequency band and offer advantages such as low loss and high power, making them widely used in communications, radar, and various electronic testing equipment. For cavity filters capable of multi-band filtering, each band has its own transmission channel, and these channels are isolated by an isolation structure to prevent signal leakage. The presence of this isolation structure reduces the overall effective area of ​​the cavity, leading to a corresponding reduction in the volume of the internal resonant cavity. This reduction in cavity cavity volume hinders frequency reduction design and increases the probability of air breakdown under high-power operation, affecting the filter's reliability. Summary of the Invention

[0005] This application provides a cavity filter that enables frequency reduction design and increases power capacity of the cavity filter without increasing its size.

[0006] In a first aspect, this application provides a cavity filter, which includes a cavity and a cover plate. The cavity includes a bottom wall and an opening end, and the cover plate can be disposed on the opening end of the cavity, with the cover plate opposite to the bottom wall of the cavity. Multiple filtering components are disposed within the cavity, each used to filter signals in different frequency bands. Each filtering component may include one or more resonant units. When the filtering component includes multiple resonant units, adjacent resonant units are coupled together. Each resonant unit may include a resonant cavity and a resonator disposed within the resonant cavity. One or more connecting windows may be provided between two adjacent filtering components, extending from the opening end of the cavity towards the bottom wall of the cavity, connecting a resonant cavity of one filtering component to a resonant cavity of another filtering component.

[0007] In this application, by setting a connectivity window, the internal volume of the two resonant cavities connected by the connectivity window is increased, the insertion loss of the resonant unit is reduced, and the frequency of the resonant unit shifts to a lower frequency. Therefore, it helps to achieve frequency reduction design in miniaturized cavity filters. In addition, under the premise of achieving frequency reduction design by setting a connectivity window, the distance requirement between the resonator and the cover plate can be reduced, and a relatively large safety distance can be maintained between the resonator and the cover plate. This reduces the probability of air breakdown in the cavity filter under high power conditions, thereby helping to achieve high power capacity design of cavity filters in a small size.

[0008] In some implementations, multiple filter components are arranged sequentially along a first direction, and the resonant units in each filter component are positioned opposite each other along the first direction. A connecting window can connect two resonant cavities in two adjacent filter components that are positioned opposite each other along the first direction, thereby effectively increasing the size of the two resonant cavities connected by the connecting window.

[0009] In some implementations, the arrangement direction of one or more resonant elements in the filter assembly is defined as a second direction, and the width of the connection window along the second direction can be greater than or equal to the width of the corresponding two resonant elements along the second direction. This design maximizes the size of the two resonant elements corresponding to the connection window, thus further reducing the difficulty of designing cavity filters for frequency reduction and high power capacity.

[0010] In some implementations, the connecting window can extend from the bottom wall of the cavity to the opening end of the cavity, thereby further increasing the size of the resonant unit, reducing the insertion loss of the resonant unit, and enabling the cavity filter to achieve further frequency reduction design.

[0011] In some implementations, one or more first isolation structures are provided between adjacent filter components. The first isolation structure is disposed on the bottom wall, and the end of the first isolation structure facing away from the bottom wall is spaced apart from the cover plate, thus forming a connecting window between the end of the first isolation structure facing away from the bottom wall and the cover plate. This design can increase the size of the two resonant units corresponding to the connecting window, and also increase the heat dissipation area of ​​the cavity by utilizing the first isolation structure, thereby improving the heat dissipation capacity of the cavity.

[0012] In some implementations, the filter assembly includes a plurality of resonant units arranged along a second direction. A second isolation structure may be provided between adjacent resonant units in the filter assembly. The second isolation structure is connected to the bottom wall and is provided with a coupling window. Adjacent resonant units are coupled through the coupling window so that each resonant unit transmits a signal to the next adjacent resonant unit through the coupling window.

[0013] In some implementations, the resonators of two adjacent resonant units in the filter assembly can be connected by coupling ribs. The coupling ribs can also enhance the coupling strength between adjacent resonant units, and the higher the height of the coupling ribs, the stronger the coupling strength between adjacent resonant units.

[0014] In some implementations, multiple connecting windows arranged along a second direction are provided between two adjacent filter components. Each connecting window corresponds one-to-one with multiple resonant elements in one filter component, and vice versa. This allows for a certain degree of increase in the size of each resonant element in the filter component. The second isolation structure includes a first substructure and a second substructure arranged at intervals along a first direction. A coupling window is formed between the first and second substructures. At least one of the first and second substructures separates two adjacent coupling windows along the second direction. This ensures the coupling performance between adjacent resonant elements while increasing their size.

[0015] In some implementations, multiple connecting windows arranged along a second direction are provided between two adjacent filter components. Each connecting window corresponds one-to-one with a plurality of resonant elements in one filter component and another corresponding one-to-one with a plurality of resonant elements in the other filter component. In at least one of the two adjacent filter components, each of the second isolation structures of the filter component is located away from the other filter component. With each of the second isolation structures of each filter component located away from the other filter component, the multiple connecting windows between the two adjacent filter components can be integrated along the second direction. This design increases the coupling strength between adjacent resonant elements, thus reducing the height of the coupling ribs between adjacent resonant elements and decreasing the Q-value loss. This allows the cavity filter to achieve frequency reduction while reducing insertion loss.

[0016] In some implementations, the cavity includes a first sidewall and a second sidewall disposed opposite to each other. The cavity filter has two filtering components: a first filtering component and a second filtering component. The first filtering component is disposed close to the first sidewall, and its second isolation structure is connected to the first sidewall. The second filtering component is disposed close to the second sidewall, and its second isolation structure is connected to the second sidewall. In this way, the multiple connecting windows between the first and second filtering components can be connected as a single unit.

[0017] In some embodiments, a coupling screw is provided between adjacent resonant units in the filter assembly. The first end of the coupling screw is threaded to the cover plate, and the second end of the coupling screw is located within the coupling window, with the second end of the coupling screw spaced apart from the bottom wall. By adjusting the depth of the coupling screw extending into the coupling window, the coupling strength between two adjacent resonant units can be adjusted.

[0018] In some implementations, the resonant unit may also include a tuning screw, the first end of which is threaded to a cover plate, and the second end of which extends into the resonator and is spaced apart from the resonator. The frequency of the resonator can be adjusted by adjusting the depth to which the tuning screw extends into the resonator. Attached Figure Description

[0019] Figure 1 is a schematic diagram of the structure of a communication device;

[0020] Figure 2 is a schematic diagram of the structure of a radio frequency processing unit;

[0021] Figure 3 is a schematic diagram of a cavity filter in the related technology;

[0022] Figure 4a shows the redundant coupling bandwidth between the resonant units of different filter components when the cavity filter has no isolation structure;

[0023] Figure 4b shows the coupling bandwidth of the main coupling between the resonant units of the filter components of the cavity filter.

[0024] Figure 5 is an exploded structural diagram of a cavity filter provided in an embodiment of this application;

[0025] Figure 6 is a partial structural schematic diagram of a cavity filter provided in an embodiment of this application;

[0026] Figure 7 is a partial structural schematic diagram of another cavity filter provided in an embodiment of this application;

[0027] Figure 8 is a partial structural schematic diagram of another cavity filter provided in an embodiment of this application.

[0028] Reference numerals in related technologies: 01-Cavity filter; 011-Cavity; 012-Filtering component; 0121-Resonant unit; 013-Isolation structure.

[0029] Reference numerals in the embodiments of this application: 1000-Communication equipment; 100-Antenna; 200-Cable; 300-Mounting component; 400-Mount; 500-RF processing unit; 510-Frequency converter; 520-Power amplifier; 530-Low noise amplifier; 540-Filter; 600-Baseband processing unit; 10-Cavity filter; 11-Cavity; 11a-Open end; 11b-Bottom wall; 11c-First side wall; 11d-Second side wall; 11e-Third side wall; 11f-Fourth side wall; 12-Cover plate; 13-Filter assembly; 13a-First filter assembly; 13b-Second filter assembly; 131-Resonant unit; 1311-Resonant cavity; 1312-Resonator; 1313-Tuning screw; 1314-Coupling window; 14-First connection port; 15-Communication window; 16-First isolation structure; 17-Second isolation structure; 171-First substructure; 172-Second substructure; 18-Coupled screw; 19-Coupled rib. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0031] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] The cavity filter provided in this application embodiment can be applied in communication equipment such as base stations and radar to filter out specific frequency points or frequencies outside of the transmitted signals of the communication equipment, thereby achieving the purpose of obtaining a specific frequency or eliminating a specific frequency.

[0033] Figure 1 is a schematic diagram of a communication device 1000, illustrated using a base station as an example. Referring to Figure 1, the base station 1000 includes a base station antenna feeder system. In practical applications, the base station antenna feeder system mainly includes an antenna 100, a cable 200, and a grounding device. The antenna 100 can be mounted on a mast 400 using a mounting bracket 300. The mounting bracket 300 can adjust the downtilt angle of the antenna 100 to adjust the signal coverage range of the antenna 100 to a certain extent.

[0034] In this embodiment, the base station 1000 may further include a radio frequency (RF) processing unit 500 and a baseband processing unit 600. The RF processing unit 500 can process the signal received by the antenna 100 and convert it into an intermediate frequency (IF) signal or a baseband signal before sending it to the baseband processing unit 600. Alternatively, the RF processing unit 500 can process the IF signal emitted by the baseband processing unit 600 and convert it into a wireless signal through the antenna 100 before transmitting it. The baseband processing unit 600 can be connected to the feed network of the antenna 100 via the RF processing unit 500. In some embodiments, the RF processing unit 500 may also be referred to as a remote radio unit (RRU), and the baseband processing unit 600 may also be referred to as a baseband unit (BBU).

[0035] The radio frequency (RF) processing unit 500 and the baseband processing unit 600 can be connected via a cable. In one embodiment, the RF processing unit 500 and the baseband processing unit 600 may be located at the distal end of the antenna 100. In another embodiment, the RF processing unit 500 may be integrated with the antenna 100, and the baseband processing unit 600 may be located at the distal end of the antenna 100. In this example, the RF processing unit 500 and the antenna 100 may be collectively referred to as an active antenna unit (AAU).

[0036] Figure 2 is a schematic diagram of a radio frequency (RF) processing unit. Referring to Figure 2, in some embodiments, the RF processing unit 500 may include devices such as a frequency converter 510, a power amplifier 520, a low-noise amplifier 530, and a filter 540. The power amplifier 520 and the low-noise amplifier 530 are connected in parallel between the frequency converter 510 and the filter 540. In the signal transmission direction, the frequency converter 510 can be used to up-convert the signal from the baseband processing unit 600. After frequency conversion, the signal is transmitted to the power amplifier 520, where it is amplified before entering the filter 540 for filtering. Finally, the antenna 100 converts the signal into electromagnetic waves for transmission. In the signal reception direction, the filter 540 can be used to filter the signal received by the antenna 100, which is then transmitted to the low-noise amplifier 530 for low-noise amplification. The low-noise amplifier 530 then transmits the signal to the frequency converter 510 for down-conversion before transmitting it to the baseband processing unit 600.

[0037] As a key component of the RF front-end circuit, the performance of the filter 540 directly affects the communication capability of the base station. Currently, common filters 540 include cavity filters and dielectric filters. Among them, cavity filters are widely used in RF processing units due to their good selectivity, low loss, and high power capacity.

[0038] Figure 3 is a schematic diagram of a cavity filter 01 in the related art. Referring to Figure 3, the cavity filter 01 includes a cavity 011, within which two filter components 012 are disposed. Each filter component 012 includes multiple resonant units 0121 coupled sequentially. The two filter components 012 are used to filter signals of different frequency bands, thus forming two transmission channels. The two filter components 012 are separated by an isolation structure 013, which enables independent transmission of signals in the two transmission channels and reduces redundant coupling between the resonant units 0121 in the two filter components 012.

[0039] However, research has verified that the redundant coupling between the resonant units of different filter components 012 has little impact on the transmission performance of their respective channels in different frequency bands. Referring to Figures 4a and 4b, Figure 4a shows the redundant coupling bandwidth between the resonant units 0121 of different filter components 012 without the isolation structure 013, and Figure 4b shows the coupling bandwidth of the main coupling between the resonant units 0121 of the filter components. It can be seen that after removing the isolation structure 013, the redundant coupling bandwidth between the resonant units 0121 of different filter components 012 is 6.5MHz-13MHz, while the coupling bandwidth of the main coupling between the resonant units 0121 within the filter component 012 is greater than 50MHz. As those skilled in the art know, the wider the coupling bandwidth, the stronger the required coupling capability. The coupling strength of redundant coupling is less than one-third of the coupling strength of the main coupling; therefore, the impact of redundant coupling on the main coupling is relatively small.

[0040] In view of this, embodiments of this application provide a cavity filter. This cavity filter achieves frequency reduction design by removing or weakening the isolation structure between different transmission channels, while simultaneously reducing the loss of the cavity filter and increasing its power capacity. The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0041] Figure 5 is an exploded structural diagram of a cavity filter 10 provided in an embodiment of this application. Referring to Figure 5, in this embodiment, the cavity filter 10 includes a cavity 11 and a cover plate 12. Both the cavity 11 and the cover plate 12 are metal structures and can be formed by die casting or machining. The cavity 11 includes an open end 11a, and the cover plate 12 is placed over the open end 11a of the cavity 11 to close the cavity 11. Exemplarily, the cover plate 12 and the cavity 11 can be fixedly connected by screws.

[0042] Figure 6 is a partial structural schematic diagram of a cavity filter 10 provided in an embodiment of this application. Referring to Figures 5 and 6 together, a plurality of filter components 13 are disposed within the cavity, and the figures show an example of two filter components 13. The plurality of filter components 13 are used to filter signals of different frequency bands, that is, each filter component 13 can be regarded as a transmission channel for a signal of one frequency band. The cavity filter 10 also includes a plurality of connection ports disposed in the cavity, and the plurality of connection ports are disposed one-to-one with the plurality of filter components 13. Each set of connection ports includes a first connection port 14 and a second connection port (not shown in the figure). The first connection port 14 and the second connection port are respectively used to connect the filter component 13 to an external device. For example, the first connection port 14 can be used to electrically connect to a power amplifier or a low noise amplifier, and the second connection port can be used to electrically connect to an antenna. In the signal transmission direction, the signal can be transmitted from the first connection port 14 through the filter component 13 to the second connection port, and in the signal reception direction, the signal can be transmitted from the second connection port through the filter component 13 to the first connection port 14.

[0043] In this embodiment, the filter assembly 13 may include one or more resonant units 131. Each resonant unit 131 includes a resonant cavity 1311 and a resonator 1312 disposed within the resonant cavity 1311. Additionally, the resonant unit 131 may also include a tuning screw 1313. The first end of the tuning screw 1313 is threaded to the cover plate 12, and the second end of the tuning screw 1313 extends into the resonator 1312, with the second end of the tuning screw 1313 spaced apart from the resonator 1312. By adjusting the depth of the tuning screw extending into the resonator 1312, the frequency of the resonator 1312 can be adjusted.

[0044] When the filter assembly 13 includes a single resonant unit 131, the resonant unit 131 is connected to the first connection port 14 and the second connection port, respectively. When the filter assembly 13 includes multiple resonant units 131, the multiple resonant units 131 are coupled sequentially to allow signals to be transmitted sequentially between the resonant units 131 of the filter assembly 13. The two resonant units 131 located at both ends of the transmission channel are connected to the first connection port 14 and the second connection port, respectively, for input and output signals. The following embodiments are all described using the example of the filter assembly 13 including multiple resonant units 131.

[0045] In some embodiments, the cavity filter 10 may be approximately hexahedral in structure. The cavity 11 includes a bottom wall 11b and a first side wall 11c, a second side wall 11d, a third side wall 11e, and a fourth side wall 11f disposed on the bottom wall. The first side wall 11c, the third side wall 11e, the second side wall 11d, and the fourth side wall 11f are connected sequentially. The first side wall 11c and the second side wall 11d are disposed opposite each other along a first direction x, and the third side wall 11e and the fourth side wall 11f are disposed opposite each other along a second direction y. The ends of the first side wall 11c, the second side wall 11d, the third side wall 11e, and the fourth side wall 11f facing away from the bottom wall are fixedly connected to the cover plate 12 by screws. The cover plate 12 is disposed opposite to the bottom wall 11b.

[0046] In some embodiments, multiple filter components 13 may be arranged sequentially along a first direction x, and multiple resonant units 131 in each filter component 13 may be arranged sequentially along a second direction y. The first connection ports 14 of the multiple sets of connection ports may be respectively disposed on the third sidewall 11e to facilitate connection with a resonant unit 131 of each filter component 13 near the third sidewall 11e, and the second connection ports of the multiple sets of connection ports may be respectively disposed on the fourth sidewall 11f to facilitate connection with a resonant unit 131 of each filter component 13 near the fourth sidewall 11f.

[0047] In some other embodiments, the plurality of resonant units 131 in the filter component 13 may also be arranged in a nonlinear manner, and correspondingly, the arrangement direction of the plurality of filter components 13 may also be nonlinear, all of which are within the protection scope of this application. In this case, the cavity filter 10 may adopt the above-described hexahedral structure, or other structural forms, which will not be described in detail here.

[0048] In one embodiment, the number of resonant units 131 in the multiple filter components 13 is the same, and in two adjacent filter components 13, the multiple resonant units 131 of one filter component 13 are respectively arranged opposite to the multiple resonant units 131 of the other filter component 13 along the first direction x. This can reduce the processing and molding difficulty of the cavity filter 10.

[0049] In this embodiment, one or more connecting windows 15 are provided between two adjacent filter components 13. The connecting window 15 can extend from the opening end 11a of the cavity to the bottom wall 11b of the cavity 11. The connecting window 15 can connect a resonant cavity 1311 of one filter component 13 with a resonant cavity 1311 of another filter component 13. Taking two filter components 13 as an example, namely the first filter component 13a and the second filter component 13b, the connecting window 15 can connect a resonant cavity 1311 of the first filter component 13a and a resonant cavity 1311 of the second filter component 13b. Exemplarily, the connecting window 15 can connect two resonant cavities 1311 of the first filter component 13a and the second filter component 13b that are arranged opposite each other along the first direction x.

[0050] With the volume of the cavity filter 10 remaining unchanged, by setting the connecting window 15, the internal volume of the two resonant cavities 1311 connected by the connecting window 15 is increased, the insertion loss of the resonant unit 131 is reduced, and the frequency of the resonant unit 131 shifts to lower frequencies. Therefore, it helps to achieve frequency reduction design in the miniaturized cavity filter 10. In addition, normally, a smaller distance between the resonator 1312 and the cover plate 12 is more conducive to the resonant unit 131 achieving low frequencies. However, under the premise of achieving frequency reduction design by setting the connecting window 15, the distance requirement between the resonator 1312 and the cover plate 12 can be reduced. That is to say, there can be a relatively large safety distance between the resonator 1312 and the cover plate 12. With the increase of the safety distance, the probability of air breakdown in high-power environments will be reduced. This provides a certain feasibility for increasing the power capacity of the cavity filter 10, enabling the cavity filter 10 to achieve high power capacity design under small size conditions.

[0051] In some embodiments, a plurality of connecting windows 15 are provided between two adjacent filter components 13. The plurality of connecting windows 15 are arranged sequentially along the second direction y. The plurality of connecting windows 15 are configured one-to-one with a plurality of resonant units 131 of one of the filter components 13, and the plurality of connecting windows 15 are configured one-to-one with a plurality of resonant units 131 of another filter component 13. In this way, the size of each resonant unit 131 in the filter component 13 can be increased to a certain extent, thereby helping to further reduce the insertion loss of the cavity filter 10 and reduce the frequency of the cavity filter 10, and improve the power capacity of the cavity filter 10.

[0052] Furthermore, the width of the connecting window 15 along the second direction y can be greater than or equal to the width of the corresponding two resonant units 131 along the second direction y. Here, the two resonant units 131 corresponding to the connecting window 15 refer to the two resonant units 131 containing the two resonant cavities 1311 connected by the connecting window 15. This design maximizes the size of the two resonant units 131 corresponding to the connecting window 15, thereby further reducing the difficulty of achieving low insertion loss, low frequency, and high power capacity design in the cavity filter 10.

[0053] Of course, in some other embodiments, the width of the connecting window 15 along the second direction y may also be smaller than the width of the corresponding two resonant units 131 along the second direction y.

[0054] Referring again to Figures 5 and 6, in this embodiment, one or more first isolation structures 16 are provided between two adjacent filter components 13. The first isolation structure 16 is disposed on the bottom wall 11b, and the end of the first isolation structure 16 facing away from the bottom wall 11b is spaced apart from the cover plate 12. The end of the first isolation structure 16 facing away from the bottom wall 11b can be formed as the aforementioned connecting window 15. Therefore, the size of the connecting window 15 is determined by the height of the first isolation structure 16. This design can increase the size of the two resonant units 131 corresponding to the connecting window 15, and can also increase the heat dissipation area of ​​the cavity 11 by utilizing the first isolation structure 16, thereby improving the heat dissipation capacity of the cavity 11. In practical applications, the height of the first isolation structure 16 can be reasonably designed according to the insertion loss, frequency, power, and heat dissipation requirements of the cavity filter 10.

[0055] In this embodiment, a second isolation structure 17 is provided between two adjacent resonant units 131 in the filter assembly 13. The second isolation structure 17 is fixed to the bottom wall 11b and is connected to the cover plate 12. The resonant cavities 1311 of two adjacent resonant units 131 are separated by the second isolation structure 17. The second isolation structure 17 is provided with a coupling window 1314. Two adjacent resonant units 131 are coupled through the coupling window 1314. Each resonant unit 131 transmits a signal to the next adjacent resonant unit 131 through the coupling window 1314.

[0056] In some embodiments, the second isolation structure 17 includes a first substructure 171 and a second substructure 172, which are arranged at intervals along a first direction x. The space between the first substructure 171 and the second substructure 172 can be formed as a coupling window 1314. By adjusting the width of the first substructure 171 and the second substructure 172 along the first direction x, the size of the coupling window 1314 can be adjusted, thereby enabling the adjustment of the coupling cavity 11 between two adjacent resonant units 131.

[0057] In one implementation, at least one of the first substructure 171 and the second substructure 172 can separate two adjacent connected windows 15 along the second direction y. In this case, the width of the connected window 15 along the second direction y is equal to the width of the corresponding two resonant units 131 along the second direction y.

[0058] For example, when there are two filter components 13, the first substructure 171 of the first filter component 13a can be connected to the first sidewall 11c, and the second substructure 172 of the first filter component 13 is positioned close to the second filter component 13b. In this case, the second substructure 172 of the first filter component 13a can separate two adjacent connected windows 15. Similarly, the second substructure 172 of the second filter component 13b can be connected to the second sidewall, and the first substructure 171 of the second filter component 13 is positioned close to the first filter component 13a. In this case, the first substructure 171 of the second filter component 13 can separate two adjacent connected windows 15. In a specific implementation, the second substructure 172 of the first filter component 13a and the corresponding first substructure 171 of the second filter component 13b can be a single integrated structure to reduce the manufacturing difficulty of the cavity 11.

[0059] In some embodiments, adjacent resonant units 131 in the filter assembly 13 may also be provided with coupling screws 18. The first end of the coupling screw 18 is threaded to the cover plate 12, and the second end of the coupling screw 18 can extend into the coupling window 1314 of the two adjacent resonant units 131, with the second end of the coupling screw 18 spaced apart from the bottom wall 11b. By adjusting the depth of the coupling screw 18 extending into the coupling window 1314, the coupling strength of the two adjacent resonant units 131 can be adjusted. Specifically, the deeper the coupling screw 18 extends into the coupling window 1314, the stronger the coupling strength of the two adjacent resonant units 131; conversely, the shallower the coupling screw 18 extends into the coupling window 1314, the weaker the coupling strength of the two adjacent resonant units 131.

[0060] In some embodiments, the resonators 1311 of adjacent resonant units 131 in the filter assembly 13 can be connected by coupling ribs 19. The coupling ribs 19 can also enhance the coupling strength between two adjacent resonant units 131, and the higher the height of the coupling ribs 19, the stronger the coupling strength between two adjacent resonant units 131.

[0061] Figure 7 is a partial structural schematic diagram of another cavity filter 10 provided in an embodiment of this application. Referring to Figure 7, in this embodiment, the structure of the filter component 13 can be designed with reference to the aforementioned embodiments, and will not be repeated here. Unlike the aforementioned embodiments, in this embodiment, a first isolation structure is no longer provided between two adjacent filter components 13, and the connecting window 15 can extend from the bottom wall 11b to the opening end 11a of the cavity 11, thereby further increasing the size of the resonant unit 131, reducing the insertion loss of the resonant unit 131, and enabling the cavity filter 10 to further achieve frequency reduction design.

[0062] In addition, in some embodiments, a first isolation structure may be provided between some resonant units 131 in the filter assembly 13 and some resonant units 131 in the adjacent filter assembly 13, and no first isolation structure is provided between other resonant units 131 in the filter assembly 13 and other resonant units 131 in the adjacent filter assembly 13. In this case, a partial connecting window 15 between two adjacent filter assemblies 13 is formed by the gap between the first isolation structure and the cover plate, and the other partial connecting window 15 extends from the bottom wall 11b to the opening end 11a of the cavity 11.

[0063] Figure 8 is a partial structural diagram of another cavity filter 10 provided in an embodiment of this application. Referring to Figure 8, in this embodiment, no first isolation structure is provided between two adjacent filter components 13, and the connecting window 15 can extend from the bottom wall 11b to the opening end 11a of the cavity 11. In addition, the second isolation structure 17 between two adjacent resonant units 131 in the filter component 13 can be a whole. For two adjacent filter components 13, each of the second isolation structures 17 of at least one filter component 13 is disposed on the side of the filter component 13 away from the other filter component 13. It is easy to understand that when the second isolation structures 17 of each filter component 13 are disposed on the side of the filter component 13 away from the other filter component 13, the multiple connecting windows 15 between the two adjacent filter components 13 can be connected as a whole along the second direction y. In this case, the width of the connecting window 15 along the second direction y is greater than the width of the corresponding two resonant units 131 along the second direction y.

[0064] For example, when there are two filter components 13, the first filter component 13a is positioned near the first sidewall 11c, and the second filter component 13b is positioned near the second sidewall 11d. The second isolation structure 17 of the first filter component 13a is connected to the first sidewall 11c, and the second isolation structure 17 of the second filter component 13b is connected to the second sidewall 11d. Thus, the multiple connecting windows 15 between the first filter component 13a and the second filter component 13b can be integrated into one unit. With this structural design, the coupling window 1314 between adjacent resonant units 131 in the filter component 13 increases, thereby increasing the coupling strength. This reduces the height of the coupling ribs 19 between adjacent resonant units 131, decreasing Q-value loss, and thus reducing insertion loss while achieving frequency reduction.

[0065] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A cavity filter, characterized in that, It includes a cavity and a cover plate. The cavity includes a bottom wall and an open end. The cover plate is placed over the open end and is disposed opposite to the bottom wall. The cavity is provided with multiple filtering components, which are used to filter signals of different frequency bands; each filtering component includes one or more resonant units, each resonant unit includes a resonant cavity and a resonator disposed in the resonant cavity, and adjacent resonant units in the filtering component are coupled. One or more connecting windows are provided between two adjacent filter components, the connecting windows connecting a resonant cavity in one filter component to a resonant cavity in the other filter component, and the connecting windows extending from the opening end toward the bottom wall.

2. The cavity filter as described in claim 1, characterized in that, The plurality of filter components are arranged sequentially along a first direction, and the resonant units in the filter components are arranged one-to-one with the resonant units in the adjacent filter components along the first direction. The connecting window connects two resonant cavities that are positioned opposite each other in the first direction in two adjacent filter components.

3. The cavity filter as described in claim 2, characterized in that, The width of the connecting window along the second direction is greater than or equal to the width of the corresponding two resonant units along the second direction, where the second direction is the arrangement direction of one or more resonant units in the filter assembly.

4. The cavity filter according to any one of claims 1-3, characterized in that, The connecting window extends from the bottom wall to the opening end.

5. The cavity filter according to any one of claims 1-3, characterized in that, One or more first isolation structures are provided between two adjacent filter components. The first isolation structure is disposed on the bottom wall, and the end of the first isolation structure facing away from the bottom wall is spaced apart from the cover plate. The communication window is formed between the end of the first isolation structure facing away from the bottom wall and the cover plate.

6. The cavity filter according to any one of claims 1-5, characterized in that, The filtering component includes a plurality of resonant units arranged along a second direction. A second isolation structure is provided between adjacent resonant units in the filtering component. The second isolation structure is connected to the bottom wall. The second isolation structure is provided with a coupling window, and two adjacent resonant units are coupled through the coupling window.

7. The cavity filter as described in claim 6, characterized in that, A plurality of connecting windows are arranged along the second direction between two adjacent filter components. Each of the plurality of connecting windows corresponds to a plurality of resonant units of one of the filter components, and the plurality of connecting windows corresponds to a plurality of resonant units of the other filter component. The second isolation structure includes a first substructure and a second substructure spaced apart along a first direction, with the first substructure and the second substructure forming the coupling window, and at least one of the first substructure and the second substructure separating two adjacent connected windows along the second direction.

8. The cavity filter as described in claim 6, characterized in that, A plurality of connecting windows are arranged along the second direction between two adjacent filter components. Each of the plurality of connecting windows corresponds to a plurality of resonant units of one of the filter components, and the plurality of connecting windows corresponds to a plurality of resonant units of the other filter component. In two adjacent filter components, each of the second isolation structures of at least one filter component is disposed on the side away from the other filter component.

9. The cavity filter as described in claim 8, characterized in that, The cavity includes a first sidewall and a second sidewall disposed opposite to each other; There are two filtering components, namely a first filtering component and a second filtering component. The first filtering component is disposed close to the first sidewall, and the second isolation structure of the first filtering component is connected to the first sidewall. The second filtering component is disposed close to the second sidewall, and the second isolation structure of the second filtering component is connected to the second sidewall.

10. The cavity filter according to any one of claims 6-9, characterized in that, A coupling screw is provided between adjacent resonant units in the filter assembly. The first end of the coupling screw is threaded to the cover plate, and the second end of the coupling screw is located inside the coupling window. The second end of the coupling screw is spaced apart from the bottom wall.

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