Cavity filter

Abstract

The utility model relates to the technical field of filters, and provides a cavity filter which comprises a cavity, a dielectric filtering unit and a single-mode resonator, the dielectric filtering unit is arranged in the cavity and is provided with a dielectric filtering channel, and the single-mode resonator is arranged in the cavity and is coupled with the dielectric filtering unit. According to the cavity filter, a plurality of single-mode resonators required by the existing design are replaced by the dielectric filtering unit, so that the occupied space in the cavity can be reduced, the miniaturization of the cavity filter is facilitated, and the problem that the overall size of the cavity filter is relatively large is solved; meanwhile, the overall weight of the cavity filter can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of filters, and in particular to a cavity filter. Background Art

[0002] Cavity filters have the advantages of mature manufacturing process, stable performance, and high power, so they are widely used. Cavity filters generally include a cavity and multiple single-mode resonators arranged in the cavity at intervals. The space occupied by multiple single-mode resonators after inter-stage coupling and cross-coupling is large, resulting in a larger overall size of the cavity filter. Utility Model Content

[0003] In view of this, an embodiment of the present application provides a cavity filter to solve the problem of the large overall size of the cavity filter.

[0004] An embodiment of the present application proposes a cavity filter, comprising a cavity, a dielectric filter unit and a single-mode resonator, wherein the dielectric filter unit is disposed in the cavity and has a dielectric filter channel, and the single-mode resonator is disposed in the cavity and coupled to the dielectric filter unit.

[0005] The cavity filter provided in the embodiment of the present application includes a cavity, a dielectric filter unit and a single-mode resonator. The dielectric filter unit and the single-mode resonator are both arranged in the cavity to filter the signal together. Since the dielectric filter unit has a complete dielectric filter channel and a high degree of integration, the size of the dielectric filter unit is relatively small. Therefore, by replacing the multiple single-mode resonators required by the existing design with the dielectric filter unit, the space occupied in the cavity can be reduced, which is conducive to the miniaturization of the cavity filter and solves the problem of the large overall size of the cavity filter. In addition, the weight of the dielectric filter unit is relatively small, which can reduce the overall weight of the cavity filter.

[0006] In some embodiments, the cavity filter further comprises a coupling connector, a first end of the coupling connector is connected to the dielectric filter unit, and a second end of the coupling connector is close to or connected to the single-mode resonator.

[0007] In some embodiments, the dielectric filter unit is welded and fixed to the bottom wall of the cavity; or, a first fixing hole is provided on the dielectric filter unit, and the dielectric filter unit is fixed to the bottom wall of the cavity by a first fixing screw passing through the first fixing hole.

[0008] In some embodiments, a socket is provided on a side of the dielectric filter unit facing the single-mode resonator, and the first end of the coupling connector is plugged into the socket.

[0009] In some embodiments, the cavity filter further includes a fixing plate, the dielectric filter unit is fixed on the fixing plate, a second fixing hole is provided on the fixing plate, and the fixing plate is fixed to the bottom wall of the cavity by a second fixing screw passing through the second fixing hole.

[0010] In some embodiments, a signal transmission layer is provided on the side of the fixing plate facing the dielectric filter unit, and a socket is provided on the side of the dielectric filter unit facing the fixing plate; a conductive block is provided in the socket, the conductive block is connected to the signal transmission layer, and the first end of the coupling connector is connected to the signal transmission layer.

[0011] In some embodiments, the fixing plate is a circuit board, and the signal transmission layer is a microstrip line formed on the circuit board.

[0012] In some embodiments, a support frame is provided on the bottom wall of the cavity, and the dielectric filter unit is fixed on the support frame.

[0013] In some embodiments, the single-mode resonator is provided with at least two;

[0014] Wherein, the dielectric filter unit is arranged between two adjacent single-mode resonators; or,

[0015] The cavity is provided with a first signal port and a second signal port, and the dielectric filter unit is provided between the single-mode resonator and the first signal port or between the single-mode resonator and the second signal port.

[0016] In some embodiments, the single-mode resonator is a metal resonator.

[0017] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or conventional technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 is a schematic diagram of the structure of a cavity filter provided in some embodiments of the present application;

[0020] Figure 2 yes Figure 1A partial cross-sectional view of the cavity filter shown;

[0021] Figure 3 yes Figure 1 The schematic diagram of the structure of the cavity filter shown here without the dielectric filter unit;

[0022] Figure 4 is a schematic diagram of the structure of a cavity filter provided in some other embodiments of the present application;

[0023] Figure 5 yes Figure 4 A partial cross-sectional view of the cavity filter shown;

[0024] Figure 6 yes Figure 4 The schematic diagram of the structure of the cavity filter shown here without the dielectric filter unit;

[0025] Figure 7 yes Figure 6 Schematic diagram of the structure without the fixing plate;

[0026] Figure 8 yes Figure 6 Structural diagram of the middle fixed plate;

[0027] Fig. 9 yes Figure 4 A schematic diagram of the structure of the dielectric filter unit;

[0028] Fig.10 is a schematic structural diagram of a cavity filter provided in some other embodiments of the present application;

[0029] Fig.11 It is a schematic diagram of the structure of the cavity filter provided in some other embodiments of the present application.

[0030] The meanings of the marks in the figure are:

[0031] 10. Cavity filter;

[0032] 11. cavity; 111. support frame; 1111. positioning step; 112. fixing column;

[0033] 12. dielectric filter unit; 121. dielectric matrix; 1211. jack; 122. resonant hole; 123. coupling structure;

[0034] 13. Single-mode resonator;

[0035] 14. Coupling connector;

[0036] 15. fixing plate; 151. signal transmission layer; 152. welding layer; 153. second fixing hole;

[0037] 16. First signal port;

[0038] 17. Second signal port;

[0039] 18. Second fixing screw;

[0040] 19. Conductive block. DETAILED DESCRIPTION

[0041] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0043] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0044] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0045] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0046] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0047] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the embodiments of the present application.

[0048] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0049] At present, metal cavity filters generally include a cavity and multiple single-mode resonators spaced apart in the cavity. The size of the single-mode resonator is relatively large. Multiple single-mode resonators perform inter-stage coupling and cross-coupling in the cavity, which will occupy a larger space in the cavity. Therefore, the size of the cavity needs to be made larger to meet the usage requirements, resulting in a larger overall size of the cavity filter.

[0050] In order to solve the problem of a large overall size of the cavity filter, this embodiment provides a cavity filter.

[0051] Please refer to Figure 1 The cavity filter 10 includes a cavity 11, a dielectric filter unit 12 and a single-mode resonator 13. The dielectric filter unit 12 is arranged in the cavity 11 and has a dielectric filter channel. The single-mode resonator 13 is arranged in the cavity 11 and coupled with the dielectric filter unit 12.

[0052] The cavity 11 is used to accommodate the dielectric filter unit 12 and the single-mode resonator 13. The shape of the cavity 11 is not limited in this application. It can be understood that the cavity 11 can be a regular cavity or an irregular cavity. When the cavity 11 is a regular cavity, the cavity 11 can be a rectangular cavity, a square cavity, etc. Among them, the cavity 11 is made of metal material, for example, the metal material can be aluminum, copper, etc.

[0053] The dielectric filter unit 12 is fixed (can be but not limited to welding, clamping, interference connection, bonding, fastener connection, etc.) in the cavity 11. Optionally, the dielectric filter unit 12 is composed of a dielectric substrate 121 and a metal layer covering the surface of the dielectric substrate 121. It can be understood that the metal layer can be a silver layer, a copper layer, a nickel layer, etc., and the dielectric substrate 121 can be a ceramic substrate.

[0054] The dielectric filter unit 12 has a complete dielectric filter channel, which can be formed by a resonance mode composed of multiple resonance holes 122 processed on the dielectric substrate 121; or, the dielectric filter channel can be formed by a resonance mode composed of multiple grooves processed on the dielectric substrate 121; or, the dielectric filter channel can be formed by a resonance mode composed of multiple chamfers processed on the dielectric substrate 121.

[0055] The single-mode resonator 13 may be a resonant column, a resonant tube, a resonant rod, a resonant plate, a resonant disk, etc. The single-mode resonator 13 may be a metal resonator, a single-mode dielectric resonator, or a single-mode dielectric loaded resonator.

[0056] The single-mode resonator 13 is disposed in the cavity 11 . It can be understood that the single-mode resonator 13 can be integrally formed with the bottom wall of the cavity 11 ; or, the single-mode resonator 13 can be fixed on the bottom wall of the cavity 11 .

[0057] When the single-mode resonator 13 is fixed on the bottom wall of the cavity 11, the single-mode resonator 13 can be directly fixed on the bottom wall of the cavity 11, for example, the single-mode resonator 13 is fixed on the bottom wall of the cavity 11 by welding, clamping, interference connection, bonding, threaded connection, fastener connection, etc.; or, a mounting platform is provided on the bottom wall of the cavity 11, and the single-mode resonator 13 is fixed on the mounting platform, for example, the single-mode resonator 13 is fixed on the mounting platform by welding, clamping, interference connection, bonding, threaded connection, fastener connection, etc.

[0058] The number of the single-mode resonators 13 is not limited in this application and can be one, two, or three or more.

[0059] The cavity filter 10 provided in the embodiment of the present application includes a cavity 11, a dielectric filter unit 12 and a single-mode resonator 13. The dielectric filter unit 12 and the single-mode resonator 13 are both arranged in the cavity 11 to filter the signal together. Since the dielectric filter unit 12 has a complete dielectric filter channel and a high degree of integration, the size of the dielectric filter unit 12 is relatively small. Therefore, by replacing the multiple single-mode resonators 13 required by the existing design with the dielectric filter unit 12, the space occupied in the cavity 11 can be reduced, which is conducive to the miniaturization of the cavity filter 10 and solves the problem of the large overall size of the cavity filter 10.

[0060] In addition, the weight of the dielectric filter unit 12 is relatively small, which can reduce the overall weight of the cavity filter 10 .

[0061] In some embodiments, the dielectric filter unit 12 is a dielectric waveguide filter. The dielectric waveguide filter includes a dielectric substrate 121 and a metal layer covering the surface of the dielectric substrate 121 . A plurality of resonant holes 122 are provided on the dielectric substrate 121 .

[0062] The resonant hole 122 may be a blind hole or a through hole. The shape of the resonant hole 122 may be a regular shape or an irregular shape. When the shape of the resonant hole 122 is a regular shape, the resonant hole 122 may be circular, rectangular, square, etc.

[0063] A plurality of coupling structures 123 are also provided on the dielectric substrate 121, and two adjacent resonant holes 122 achieve inter-stage coupling or cross coupling through the coupling structures 123. The coupling structures 123 may be coupling slots, coupling holes, and the like.

[0064] Optionally, the dielectric matrix 121 is a plate-shaped structure, and the dielectric matrix 121 is parallel or nearly parallel to the bottom wall of the cavity 11. In this way, more resonance holes 122 can be set on the large surface of the dielectric matrix 121, wherein the large surface of the dielectric matrix 121 refers to the side surface that is parallel or nearly parallel to the bottom wall of the cavity 11.

[0065] The extension direction of the center line of the resonance hole 122 is the depth direction of the cavity 11. Figure 2 Direction indicated by the arrow.

[0066] By arranging a plurality of resonant holes 122 on the dielectric substrate 121 of the dielectric waveguide filter, the plurality of resonant holes 122 can form a complete dielectric filter channel; moreover, the size of the resonant holes 122 is relatively small, which is conducive to arranging more resonant holes 122 on the dielectric substrate 121 to replace more single-mode resonators 13, thereby further reducing the space occupied in the cavity 11. Please also refer to Figure 1 and Figure 2 In some embodiments, the cavity filter 10 further includes a coupling connector 14 , a first end of the coupling connector 14 is connected to the dielectric filter unit 12 , and a second end of the coupling connector 14 is close to or connected to the single-mode resonator 13 .

[0067] The coupling connector 14 is used to achieve coupling between the dielectric filter unit 12 and the single-mode resonator 13, so that signals are transmitted between the dielectric filter unit 12 and the single-mode resonator 13. Optionally, the coupling connector 14 is made of metal material.

[0068] It can be understood that the coupling connector 14 can be a rod-shaped structure, a plate-shaped structure, a sheet-shaped structure, etc., and the coupling connector 14 can also be a connector. When the coupling connector 14 is a rod-shaped structure, the coupling connector 14 can be a cylindrical structure, a prismatic structure, etc.

[0069] The first end of the coupling connector 14 is connected to the dielectric filter unit 12 , and the first end of the coupling connector 14 may be connected to the dielectric substrate 121 , or may be connected to a metal layer on the surface of the dielectric substrate 121 .

[0070] It should be noted that the first end of the coupling connector 14 and the dielectric filter unit 12 may be connected by welding, plugging, crimping, overlapping, fastener connection, threaded connection, etc.

[0071] It should also be noted that the first end of the coupling connector 14 can be electrically connected to the dielectric filter unit 12, or can be insulated to form a capacitive coupling. When the first end of the coupling connector 14 is electrically connected to the dielectric filter unit 12, the first end of the coupling connector 14 can only contact the metal layer on the surface of the dielectric substrate 121, or the first end of the coupling connector 14 is connected to the dielectric substrate 121, and a metal layer is provided at the position where the dielectric substrate 121 and the coupling connector 14 are connected. When the first end of the coupling connector 14 is insulated to the dielectric filter unit 12, an insulating sheet, an insulating block or an insulating sleeve can be provided between the two, or the first end of the coupling connector 14 is connected to the dielectric substrate 121, and no metal layer is provided at the position where the dielectric substrate 121 and the coupling connector 14 are connected.

[0072] The second end of the coupling connector 14 is close to the single-mode resonator 13, which means that the second end of the coupling connector 14 is spaced apart from the single-mode resonator 13, and the spacing distance between the second end of the coupling connector 14 and the single-mode resonator 13 meets the coupling requirement; at this time, the coupling amount is relatively small. If it is necessary to further increase the coupling amount, the second end of the coupling connector 14 can be connected to the single-mode resonator 13, and the second end of the coupling connector 14 can be welded to the single-mode resonator 13, but is not limited to.

[0073] It should be noted that the second end of the coupling connector 14 and the single-mode resonator 13 may be connected by welding, plugging, crimping, overlapping, fastener connection, threaded connection, etc.

[0074] It should also be noted that the second end of the coupling connector 14 and the single-mode resonator 13 may be electrically connected or insulated to form a capacitive coupling. When the second end of the coupling connector 14 and the single-mode resonator 13 are insulated, an insulating sheet, an insulating block, an insulating sleeve or other components may be provided between the two.

[0075] By providing the coupling connector 14, the coupling connector 14 serves as a signal input / output interface of the dielectric filter unit 12, which facilitates coupling of the dielectric filter unit 12 with other filter components (such as the single-mode resonator 13) in the cavity 11 to achieve signal transmission and processing.

[0076] In some embodiments, the dielectric filter unit 12 is fixed on the bottom wall of the cavity 11 by welding.

[0077] It can be understood that the dielectric filter unit 12 can be directly welded and fixed on the bottom wall of the cavity 11, in which case the dielectric filter unit 12 can be designed to be thicker. Alternatively, a support frame 111 can be provided on the bottom wall of the cavity 11, and the dielectric filter unit 12 can be welded and fixed on the support frame 111, in which case the dielectric filter unit 12 can be designed to be thinner.

[0078] It should be noted that the thickness direction of the dielectric filter unit 12 is consistent with the depth direction of the cavity 11 .

[0079] The dielectric filter unit 12 is fixed in the cavity 11 by welding. After being fixed, the dielectric filter unit 12 has good stability and a long service life.

[0080] In some other embodiments, a first fixing hole is provided on the dielectric filter unit 12 , and the dielectric filter unit 12 is fixed to the bottom wall of the cavity 11 by a first fixing screw passing through the first fixing hole.

[0081] It can be understood that a threaded hole can be provided on the bottom wall of the cavity 11, the dielectric filter unit 12 is arranged close to the bottom wall of the cavity 11, and the first fixing screw passes through the first fixing hole and is screwed into the threaded hole to fix the dielectric filter unit 12 on the bottom wall of the cavity 11. In this case, the dielectric filter unit 12 can be designed to be thicker. Alternatively, a support frame 111 can be provided on the bottom wall of the cavity 11, the support frame 111 is provided with a threaded hole, the dielectric filter unit 12 is supported on the support frame 111, the first fixing screw passes through the first fixing hole and is screwed into the threaded hole to fix the dielectric filter unit 12 on the support frame 111. In this case, the dielectric filter unit 12 can be designed to be thinner.

[0082] The dielectric filter unit 12 is fixed to the bottom wall of the cavity 11 by the first fixing screw, which is convenient for installation and removal of the dielectric filter unit 12 and for subsequent maintenance and repair.

[0083] In other embodiments, the dielectric filter unit 12 may be fixed to the bottom wall of the cavity 11 by bonding, interference connection, snap connection, etc.

[0084] Please refer to Figure 2In some embodiments, a plug hole 1211 is provided on a side of the dielectric filter unit 12 facing the single-mode resonator 13 , and a first end of the coupling connector 14 is plugged into the plug hole 1211 .

[0085] The first end of the coupling connector 14 is inserted into the jack 1211. It is understood that the jack 1211 can have various shapes to better match the coupling connector 14. For example, the jack 1211 can be a circular hole, a rectangular hole, an elliptical hole, a bar hole, etc. The jack 1211 is a blind hole.

[0086] In order to ensure the stability of the first end of the coupling connector 14 when inserted into the socket 1211, it can be understood that the first end of the coupling connector 14 can be interference fit with the socket 1211; or, the first end of the coupling connector 14 can be transition fit or clearance fit with the socket 1211, and the first end of the coupling connector 14 is welded and fixed in the socket 1211.

[0087] By adopting the above technical solution, the dielectric filter unit 12 is directly coupled to the single-mode resonator 13 through the coupling connector 14, and no additional components are required, which simplifies the structure, facilitates the assembly of the cavity filter 10, and improves the assembly efficiency. Moreover, it is conducive to the arrangement of the coupling connector 14. For example, when the coupling connector 14 is a coupling rod, the coupling rod can be a straight rod, that is, the coupling rod is parallel or nearly parallel to the bottom wall of the cavity 11. The structure of the coupling rod is relatively simple, which is conducive to achieving the coupling of the dielectric filter unit 12 and the single-mode resonator 13.

[0088] In other embodiments, the jack 1211 may be disposed on the side of the dielectric filter unit 12 facing toward or facing away from the bottom wall of the cavity 11, that is, the opening of the jack 1211 faces toward or faces away from the bottom wall of the cavity 11; in this case, the arrangement of the coupling connector 14 needs to be appropriately adjusted, for example, when the coupling connector 14 is a coupling rod, the coupling rod needs to be a zigzag rod, which includes at least one vertical section and a transverse section, such as an L-shaped rod, a U-shaped rod, etc., in order to achieve coupling between the dielectric filter unit 12 and the single-mode resonator 13. The vertical section is perpendicular or nearly perpendicular to the bottom wall of the cavity 11, and the transverse section is parallel or nearly parallel to the bottom wall of the cavity 11.

[0089] Please also refer to Figure 4 , Figure 5 and Figure 8 In some embodiments, the cavity filter 10 further includes a fixing plate 15, the dielectric filter unit 12 is fixed on the fixing plate 15, a second fixing hole 153 is provided on the fixing plate 15, and the fixing plate 15 is fixed to the bottom wall of the cavity 11 by a second fixing screw 18 passing through the second fixing hole 153.

[0090] It can be understood that the dielectric filter unit 12 is fixed to the bottom wall of the cavity 11 through the fixing plate 15. The fixing plate 15 can be a metal plate; or, the fixing plate 15 can be an insulating plate; or, the fixing plate 15 can include an insulating plate and a metal layer provided on the surface of the insulating plate.

[0091] The dielectric filter unit 12 can be fixed on the fixing plate 15 in various ways. For example, the dielectric filter unit 12 can be fixed on the fixing plate 15 by welding, or the dielectric filter unit 12 can be fixed on the fixing plate 15 by bonding, clamping, interference connection, etc.

[0092] The second fixing hole 153 is for the second fixing screw 18 to pass through. Optionally, four second fixing holes 153 are provided, and the four second fixing holes 153 are respectively provided at the four corners of the fixing plate 15; of course, two, three, five or more second fixing holes 153 can also be provided.

[0093] Optionally, please also refer to Figure 6 and Figure 7 A fixing column 112 is provided on the bottom wall of the cavity 11, and a threaded hole is provided at one end of the fixing column 112 away from the bottom wall of the cavity 11. The fixing column 112 can be integrally formed with the bottom wall of the cavity 11, and the fixing column 112 can also be fixed on the bottom wall of the cavity 11 (can be but not limited to welding, screw connection, clamping, interference connection, etc.).

[0094] During installation, the fixing plate 15 is first placed on the fixing column 112, and the second fixing hole 153 is arranged corresponding to the threaded hole. Then, the second fixing screw 18 is passed through the second fixing hole 153 and screwed into the threaded hole to fix the fixing plate 15 on the fixing column 112. Before the fixing plate 15 is fixed on the fixing column 112, the dielectric filter unit 12 may be fixed on the fixing plate 15 first; or, after the fixing plate 15 is fixed on the fixing column 112, the dielectric filter unit 12 may be fixed on the fixing plate 15.

[0095] Optionally, a support frame 111 is further provided on the bottom wall of the cavity 11 , and the support frame 111 can support the middle position of the fixing plate 15 to ensure the stability of the dielectric filter unit 12 after being fixed.

[0096] Optionally, four fixing columns 112 are provided, and the supporting frame 111 is disposed between the four fixing columns 112 .

[0097] Since the dielectric substrate 121 of the dielectric filter unit 12 is usually brittle, if a first fixing hole is processed on the dielectric substrate 121 and the dielectric substrate 121 is directly fixed to the bottom wall of the cavity 11 by a first fixing screw, the dielectric substrate 121 may be fractured, affecting its normal use.

[0098] In this embodiment, the dielectric filter unit 12 is first fixed (by, but not limited to, welding, bonding, etc.) on the fixing plate 15, and then the fixing plate 15 is fixed to the bottom wall of the cavity 11 by the second fixing screw 18. This facilitates the disassembly and assembly of the dielectric filter unit 12 in the cavity 11 while avoiding the dielectric matrix 121 from being crushed.

[0099] Please also refer to Figure 5 , Figure 6 and Fig. 9 In an embodiment in which the cavity filter 10 includes a fixing plate 15, a signal transmission layer 151 is provided on a side of the fixing plate 15 facing the dielectric filter unit 12, and a socket 1211 is provided on a side of the dielectric filter unit 12 facing the fixing plate 15; a conductive block 19 is provided in the socket 1211, and the conductive block 19 is connected to the signal transmission layer 151, and a first end of the coupling connector 14 is connected to the signal transmission layer 151.

[0100] Optionally, the signal transmission layer 151 is a conductive metal layer, for example, a copper layer, a silver layer, etc.

[0101] Optionally, the dielectric filter unit 12 is welded and fixed on the fixing plate 15 , and a welding layer 152 is provided on a side of the fixing plate 15 facing the dielectric filter unit 12 ; wherein the welding layer 152 may be a copper layer, a silver layer or the like.

[0102] It should be noted that the signal transmission layer 151 needs to be separated from the welding layer 152 , that is, there is a gap between the signal transmission layer 151 and the welding layer 152 to prevent the welding layer 152 from affecting the signal transmission of the signal transmission layer 151 .

[0103] Optionally, the plug hole 1211 is a blind hole. The plug hole 1211 can have various shapes to better match with the conductive block 19. For example, the plug hole 1211 can be a circular hole, a rectangular hole, an elliptical hole, a bar hole, etc.

[0104] Optionally, the conductive block 19 can be made of a metal material, such as copper, aluminum, etc.; the conductive block 19 is in the socket 1211 and connected to the signal transmission layer 151. It can be understood that the conductive block 19 can be independently arranged, and the conductive block 19 is fixed (including but not limited to welding, bonding, etc.) in the socket 1211 and then abuts against the signal transmission layer 151. At this time, the conductive block 19 needs to protrude from the surface of the dielectric filter unit 12 to ensure that the conductive block 19 is effectively in contact with the signal transmission layer 151; or, the conductive block 19 is first fixed (including but not limited to welding, bonding, etc.) on the signal transmission layer 151, and then inserted into the socket 1211.

[0105] It can be understood that the first end of the coupling connector 14 can be connected to the signal transmission layer 151 by welding, bonding, etc.

[0106] By adopting the above technical solution, while the fixing plate 15 functions to fix the dielectric filter unit 12, since the two ends of the coupling connector 14 are respectively connected to the signal transmission layer 151 and the single-mode resonator 13 on the fixing plate 15, the fixing plate 15 also functions to lead out the signal in the dielectric filter unit 12, so as to realize the coupling between the dielectric filter unit 12 and the single-mode resonator 13. Moreover, compared with the first end of the coupling connector 14 being directly connected to the dielectric filter unit 12, connecting the first end of the coupling connector 14 to the signal transmission layer 151 on the fixing plate 15 can reduce the position accuracy and processing accuracy of the first end of the coupling connector 14 and improve the installation efficiency.

[0107] In other embodiments, the fixing plate 15 only functions to fix the dielectric filter unit 12, and the two ends of the coupling connector 14 are directly connected to the dielectric filter unit 12 and the single-mode resonator 13 respectively, so as to realize the coupling between the dielectric filter unit 12 and the single-mode resonator 13.

[0108] In some embodiments, the fixing plate 15 is a circuit board, and the signal transmission layer 151 is a microstrip line formed on the circuit board.

[0109] Since the signal transmission layer 151 is a microstrip line formed on the circuit board, it can be etched into the required shape according to needs, which is convenient for the production of the signal transmission layer 151.

[0110] In other embodiments, the fixing plate 15 may include a plastic plate and a metal layer adhered to the plastic plate, and the metal layer constitutes the signal transmission layer 151.

[0111] Please also refer to Figure 2 and Figure 3 , in some embodiments, a support frame 111 is provided on the bottom wall of the cavity 11, and the dielectric filter unit 12 is fixed on the support frame 111.

[0112] It can be understood that the shape of the support frame 111 can be various, such as a rectangular frame structure, a Japanese character structure, a Chinese character structure, etc.

[0113] Among them, the support frame 111 can be integrally formed with the bottom wall of the cavity 11; or, the support frame 111 can be fixed (which can be but is not limited to welding, bonding, clamping, interference connection, fastener connection, etc.) on the bottom wall of the cavity 11.

[0114] Optionally, a positioning step 1111 is provided at the edge of the support frame 111, and the positioning step 1111 can position the dielectric filter unit 12 in the direction parallel to the bottom wall of the cavity 11 to ensure the position accuracy of the dielectric filter unit 12.

[0115] By adopting the above technical solution, the support frame 111 can lift the dielectric filter unit 12. Since the resonant part of the single-mode resonator 13 has a certain height relative to the bottom wall of the cavity 11, the dielectric filter unit 12 is lifted to facilitate the coupling of the dielectric filter unit 12 with the single-mode resonator 13, and at the same time, the thickness of the dielectric filter unit 12 can be reduced; and when the coupling connector 14 is set, the coupling connector 14 does not need to be bent, and the coupling connector 14 can be designed as a simple straight line type, which is conducive to the simplification of the structure of the coupling connector 14.

[0116] In some embodiments, please refer to Figure 1 The cavity 11 is provided with a first signal port 16 and a second signal port 17 , at least two single-mode resonators 13 are provided, and the dielectric filter unit 12 is provided between two adjacent single-mode resonators 13 .

[0117] A radio frequency connector may be provided at the first signal port 16 and the second signal port 17 .

[0118] Optionally, two single-mode resonators 13 are provided, and the dielectric filter unit 12 is provided between the two single-mode resonators 13 , wherein one single-mode resonator 13 is provided between the first signal port 16 and the dielectric filter unit 12 , and the other single-mode resonator 13 is provided between the dielectric filter unit 12 and the second signal port 17 .

[0119] In other embodiments, please refer to Fig.10 A first signal port 16 and a second signal port 17 are provided on the cavity 11, and the dielectric filter unit 12 is provided between the single-mode resonator 13 and the first signal port 16. At this time, one, two, three or more single-mode resonators 13 can be provided between the dielectric filter unit 12 and the second signal port 17.

[0120] In other embodiments, please refer to Fig.11 A first signal port 16 and a second signal port 17 are provided on the cavity 11, and the dielectric filter unit 12 is provided between the single-mode resonator 13 and the second signal port 17. At this time, one, two, three or more single-mode resonators 13 can be provided between the first signal port 16 and the dielectric filter unit 12.

[0121] In some embodiments, the single-mode resonator 13 is a metal resonator.

[0122] It can be understood that the single-mode resonator 13 is made of metal materials, such as aluminum, steel, copper, iron, etc.

[0123] By adopting the above technical solution, the resonant frequency of the dielectric filter unit 12 is relatively high, while the resonant frequency of the metal resonator is relatively low. By simultaneously arranging the dielectric filter unit 12 and the metal resonator in the cavity 11, the cavity filter 10 meets the requirements of the medium resonant frequency and is suitable for a medium frequency filter.

[0124] In other embodiments, the single-mode resonator 13 may also be a single-mode dielectric resonator. It can be understood that the single-mode resonator 13 is made of non-metallic material (which may be but is not limited to ceramic).

[0125] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A cavity filter, characterized in that: The invention comprises a cavity, a dielectric filter unit and a single-mode resonator. The dielectric filter unit is arranged in the cavity and has a dielectric filter channel. The single-mode resonator is arranged in the cavity and coupled with the dielectric filter unit.

2. The cavity filter according to claim 1, characterized in that: The cavity filter further comprises a coupling connector, a first end of which is connected to the dielectric filter unit, and a second end of which is close to or connected to the single-mode resonator.

3. The cavity filter according to claim 2, characterized in that: The dielectric filter unit is welded and fixed on the bottom wall of the cavity; or, a first fixing hole is provided on the dielectric filter unit, and the dielectric filter unit is fixed on the bottom wall of the cavity by a first fixing screw passing through the first fixing hole.

4. The cavity filter according to claim 3, characterized in that: A plug hole is provided on a side of the dielectric filter unit facing the single-mode resonator, and the first end of the coupling connector is plugged into the plug hole.

5. The cavity filter according to claim 2, characterized in that: The cavity filter further comprises a fixing plate, the dielectric filter unit is fixed on the fixing plate, a second fixing hole is provided on the fixing plate, and the fixing plate is fixed to the bottom wall of the cavity by a second fixing screw passing through the second fixing hole.

6. The cavity filter according to claim 5, characterized in that: A signal transmission layer is provided on the side of the fixing plate facing the dielectric filter unit, and a socket is provided on the side of the dielectric filter unit facing the fixing plate; a conductive block is provided in the socket, the conductive block is connected to the signal transmission layer, and the first end of the coupling connector is connected to the signal transmission layer.

7. The cavity filter according to claim 6, characterized in that: The fixing plate is a circuit board, and the signal transmission layer is a microstrip line formed on the circuit board.

8. The cavity filter according to claim 2, characterized in that: A support frame is provided on the bottom wall of the cavity, and the dielectric filter unit is fixed on the support frame.

9. The cavity filter according to any one of claims 1 to 8, characterized in that: The single-mode resonator is provided with at least two; Wherein, the dielectric filter unit is arranged between two adjacent single-mode resonators; or, The cavity is provided with a first signal port and a second signal port, and the dielectric filter unit is provided between the single-mode resonator and the first signal port or between the single-mode resonator and the second signal port.

10. The cavity filter according to any one of claims 1 to 8, characterized in that: The single-mode resonator is a metal resonator.

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