A filter

Abstract

The present application provides a filter, including: a resonant cavity, a resonant rod, a tuning screw, a resonant cover, a connector, a conductor, a port piece and a mounting seat, wherein the connector, the conductor and the port piece are all arranged on the mounting seat, and the two ends of the conductor are respectively vertically connected to the connector and the port piece, the resonant cavity is a frame structure with an opening on one side, the resonant rod is arranged in the resonant cavity, the resonant cover is arranged on the resonant cavity and seals the opening, the tuning screw is arranged on the resonant cover and extends into the resonant cavity, an extension boss is arranged on one side of the resonant cavity, a through groove is arranged on the side wall of the resonant cavity close to the extension boss, the mounting seat is arranged on the extension boss and the port piece is electromagnetically coupled to the resonant rod through the through groove, and the plug-in surface of the tuning screw and the connector are located on the same side. The tuning screw and the plug-in surface of the connector of the filter of the present application are located on the same side, and it also has the advantages of good electrical performance, high reliability, small size and low manufacturing cost.

Description

Technical Field

[0001] The present application belongs to the technical field of communication equipment, and more specifically, relates to a filter. Background Art

[0002] As a key component of the communication system, filters are widely used in various mobile communication systems. With the development of the wireless communication industry, RF communication systems have higher and higher requirements for the integration, modularization and integration of filters, making the filter dimensions smaller and smaller. In particular, the thickness allocated to the filter module in the base station system is limited, which makes the thickness requirements of the filter higher and higher.

[0003] When the connector plug-in interface that connects the filter module to the RRU (Remote Radio Unit) and the tuning screw of the filter are located on the same side, how to enable the RF signal to enter the resonant cavity of the filter through the connector and achieve port coupling becomes a problem that the filter developers must solve.

[0004] The current practice is to process a groove for fixing the wire soldering seat on the side wall of the resonant cavity of the filter module near the connector. The connector uses a connector with a coaxial cable at the tail. After the wire soldering seat is welded to the shielding layer of the coaxial cable, it is placed in the groove. The coaxial cable is then welded to the tap piece in the resonant cavity, and the tap piece is then welded to the tuning rod in the resonant cavity, thereby realizing the transmission of the RF signal. In the actual tuning process, the shielding performance of the RF signal is improved by increasing the processing accuracy of the depth of the groove and the height of the wire soldering seat, reducing the gap between the wire soldering seat and the tuning cover plate and between the wire soldering seat and the resonant cavity. In this method, the plug-in end of the connector is fixed to the resonant cavity through a flange structure, and the coaxial cable is bent and laid on the resonant cavity.

[0005] The above-mentioned method of radio frequency signal entering the resonant cavity has the following disadvantages:

[0006] 1. Because there are many welded parts in the resonant cavity and the connector installation requires a large space, the resonant cavity is large.

[0007] 2. Coaxial cable has bending radius requirements. Coaxial cable wiring requires a certain amount of space. The smaller the diameter of the coaxial cable, the smaller the bending radius, and the smaller the space required for wiring. However, the RF signal insertion loss rate of the coaxial cable is greater. In addition, the coaxial cable needs to occupy space, so the space used for cavity arrangement in the resonant cavity is significantly reduced, which seriously affects the performance of the filter, resulting in relatively low performance of the filter.

[0008] 3. Since the frequency-closing effect of the RF signal is related to the processing accuracy of the wire holder and the groove, the manufacturing cost is high. Summary of the invention

[0009] The purpose of the embodiments of the present application is to provide a filter to solve the technical problems in the prior art that when the tuning screw and the plug-in mating surface of the connector are located on the same side, the filter has high manufacturing cost, low performance and large size.

[0010] To achieve the above-mentioned purpose, the technical solution adopted in the present application is: a filter, comprising: a resonant cavity, a resonant rod, a tuning screw, a resonant cover, a connector, a conductor, a port piece and a mounting seat, wherein the connector, the conductor and the port piece are all arranged on the mounting seat, and the two ends of the conductor are respectively vertically connected to the connector and the port piece, the resonant cavity is a frame structure with an opening on one side, the resonant rod is arranged in the resonant cavity, the resonant cover is arranged on the resonant cavity and seals the opening, the tuning screw is arranged on the resonant cover and extends into the resonant cavity, an extension boss is provided on one side of the resonant cavity, a through groove is provided on the side wall of the resonant cavity close to the extension boss, the mounting seat is arranged on the extension boss and the port piece is electromagnetically coupled to the resonant rod through the through groove, and the tuning screw and the plug-in surface of the connector are located on the same side.

[0011] In one embodiment, the mounting seat includes a flange, a mounting portion provided on the flange, and a plug-in portion provided on the mounting portion, the mounting portion and the plug-in portion have the same extension direction and are perpendicular to the flange, a first mounting hole is provided on the mounting portion, a second mounting hole is provided on the plug-in portion and is vertically connected to the first mounting hole, the connector is provided in the first mounting hole, the conductor is provided in the second mounting hole, and the port piece is provided on the outer surface of the plug-in portion and is placed in the resonant cavity through the through slot.

[0012] In one embodiment, a long groove whose length direction is perpendicular to the length direction of the through groove is provided on the side wall of the through groove, one end of the plug-in portion is plugged into the long groove, and both ends of the plug-in portion are connected to the resonance cover body.

[0013] In one embodiment, a support body is disposed in the second mounting hole, the conductor is disposed in the second mounting hole through the support body, and the conductor is coaxially disposed with the second mounting hole.

[0014] In one embodiment, the second mounting hole is a countersunk hole.

[0015] In one embodiment, the port piece includes a circular ring terminal and a U-shaped portion connected to the circular ring terminal, the U-shaped portion includes a first folding piece, a connecting piece and a second folding piece, the circular ring terminal is connected to the first folding piece, the second folding piece is connected to the conductor, and the circular ring terminal is fixed to the outer surface of the plug-in portion by a fastener.

[0016] In one embodiment, the conductor and the second folding piece are integrally formed or welded.

[0017] In one embodiment, the end surface of the plug-in portion inserted into the elongated groove is in clearance fit with the bottom surface of the elongated groove.

[0018] In one embodiment, the plug-in portion is provided with a plurality of third mounting holes on the end surface close to the resonance cover plate, and the resonance cover plate is provided with a first threaded hole coaxially arranged with the third mounting hole, and a fastener is threaded at the first threaded hole and extends into the third mounting hole.

[0019] In one embodiment, a resonance platform is provided in the resonance cavity, and the resonance rod is provided on the resonance platform.

[0020] The filter provided by the present application has the following beneficial effects:

[0021] 1. The connector and the port piece are vertically connected through a conductor, and are installed on the extended boss through a mounting seat, so that the RF signal enters the resonant cavity when the tuning screw and the plug-in surface of the connector are on the same side, and the position where the RF signal enters the resonant cavity can be adjusted by changing the length of the conductor, thereby increasing the flexibility of the filter cavity arrangement; at the same time, in the same space, the insertion loss of the conductor is much smaller than that of the coaxial cable, so the insertion loss performance of the filter can be effectively reduced, thereby improving the performance of the filter; omitting the cable can reduce the cost of the filter and make the delay of the RF signal controllable.

[0022] 2. The port piece and the resonant rod adopt non-contact electromagnetic coupling instead of traditional feeding coupling, thereby eliminating the solder joints between the port piece and the resonant rod, avoiding welding inside the resonant cavity, omitting the welding space, reducing the overall size of the filter and the production cost, and at the same time achieving vertical connection between the port piece, connector and conductor through the mounting seat, simplifying the installation difficulty, so that the filter of the present application has the advantages of good electrical performance, high reliability and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] 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 the description of the prior art 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.

[0024] Figure 1 A schematic diagram of the overall structure of the filter provided in an embodiment of the present application;

[0025] Figure 2 A schematic cross-sectional view of a filter according to an embodiment of the present application;

[0026] Figure 3 A schematic diagram of the structure of a resonant cavity in a filter provided in an embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of a mounting base in a filter provided in an embodiment of the present application;

[0028] Figure 5 A schematic cross-sectional view of a mounting seat in a filter provided in an embodiment of the present application;

[0029] Figure 6 A schematic diagram of the structure of a port plate in a filter provided in an embodiment of the present application.

[0030] Among them, the reference numerals in the figure are:

[0031] 1. Resonant cavity; 11. Resonant platform; 111. Second threaded hole; 12. Through groove; 13. Long groove; 2. Resonant rod; 3. Tuning screw; 31. Nut; 4. Resonant cover; 41. First threaded hole; 5. Connector; 6. Conductor; 61. Support body; 7. Port piece; 71. Ring terminal; 72. U-shaped part; 721. First folding piece; 722. Connecting piece; 723. Second folding piece; 8. Mounting seat; 81. Flange; 811. Fifth mounting hole; 812. Protruding ring; 82. Mounting part; 821. First mounting hole; 83. Plug-in part; 831. Second mounting hole; 832. Third mounting hole; 833. Fourth mounting hole; 84. Fastener; 9. Extended boss; 91. Third threaded hole. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0034] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0035] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0036] like Figure 1-Figure 3 As shown, the filter provided in the embodiment of the present application is now described. The filter comprises: a resonant cavity 1, a resonant rod 2, a tuning screw 3, a resonant cover plate 4, a connector 5, a conductor 6, a port plate 7 and a mounting seat 8.

[0037] Among them, the connector 5, the conductor 6 and the port piece 7 are all arranged on the mounting seat 8, and the two ends of the conductor 6 are vertically connected to the connector 5 and the port piece 7 respectively; the resonant cavity 1 is a frame structure with an opening on one side. In order to simplify the structural complexity of the resonant cavity 1, the resonant rod 2 is arranged in the resonant cavity 1, and the resonant cover plate 4 is detachably arranged on the resonant cavity 1 and seals the opening to achieve a shielding effect. In this embodiment, the resonant cover plate 4 is detachably fixed to the resonant cavity 1 by screws, and in other embodiments, the resonant cover plate 4 is welded to the resonant cavity 1; the tuning screw 3 is arranged on the resonant cover plate 4 and extends into the resonant cavity 1; an extension boss 9 is provided on one side of the resonant cavity 1, and the extension boss 9 is integrally formed with the resonant cavity 1. A through groove 12 is provided on the side wall of the resonant cavity 1 close to the extension boss 9, and the through groove 12 realizes the internal and external connection of the resonant cavity 1, and the mounting seat 8 is arranged on the extension boss 9 and electromagnetically couples the port piece 7 with the resonant rod 2 through the through groove 12, and the plug-in surface of the tuning screw 3 and the connector 5 are located on the same side.

[0038] The filter provided in the embodiment of the present application has the following advantages:

[0039] 1. The connector 5 and the port piece 7 are vertically connected through the conductor 6, and are installed on the extension boss 9 through the mounting seat 8, so that the radio frequency signal enters the resonance cavity 1 when the plug-in and unplug surfaces of the tuning screw 3 and the connector 5 are on the same side, and the position where the radio frequency signal enters the resonance cavity 1 can be adjusted by changing the length of the conductor 6, thereby increasing the flexibility of the filter cavity arrangement; at the same time, in the same space, the loss of the conductor 6 to the radio frequency signal is much smaller than the insertion loss of the coaxial cable, so the performance of the filter can be effectively improved.

[0040] 2. The port piece 7 and the resonance rod 2 adopt non-contact electromagnetic coupling instead of traditional feeding coupling, thereby eliminating the solder joint between the port piece 7 and the resonance rod 2, avoiding welding inside the resonance cavity 1, omitting the welding space and process, and reducing the overall size of the filter and the production cost; at the same time, the port piece 7 and the conductor 6 are vertically connected, and the connector 5 and the conductor 6 are vertically connected through the mounting seat 8, which simplifies the installation difficulty and omits the cable, which can ensure that the delay of the RF signal is controllable, so that the filter of the present application has the advantages of good electrical performance, high reliability and low manufacturing cost.

[0041] like Figure 4 and Figure 5 As shown, in this embodiment, the mounting seat 8 includes a flange 81, a mounting portion 82 provided on the flange 81, and a plug-in portion 83 provided on the mounting portion 82. The flange 81 is used to realize the connection between the mounting portion 82 and the extension boss 9, the mounting portion 82 is a hollow cylindrical structure, the plug-in portion 83 is a rectangular block structure, and the plug-in portion 83 is connected to the mounting portion 82 through a connecting portion. Specifically, the mounting seat 8 is an integrated structure to ensure production accuracy.

[0042] like Figure 3-Figure 5 As shown, in this embodiment, the length directions of the mounting portion 82 and the plug-in portion 83 are parallel and perpendicular to the flange 81. When the flange 81 is installed on the extension boss 9, the extension directions of the mounting portion 82 and the plug-in portion 83 are the same as the length direction of the tuning screw 3, so that the plug-in surface of the connector 5 and the tuning screw 3 are on the same side of the filter.

[0043] like Figure 2 , Figure 4 and Figure 5As shown, specifically, a first mounting hole 821 is provided on the mounting portion 82, a second mounting hole 831 is provided on the plug-in portion 83 and is vertically connected to the first mounting hole 821, the connector 5 is provided in the first mounting hole 821, the conductor 6 is provided in the second mounting hole 831, and the port piece 7 is provided on the outer surface of the plug-in portion 83 and is placed in the resonant cavity 1 through the through slot 12. One end of the conductor 6 is vertically welded to the inner core of the connector 5 at the connection point between the first mounting hole 821 and the second mounting hole 831, and the other end of the conductor 6 extends out of the second mounting hole 831 and is connected to the port piece 7, and the port piece 7 realizes electromagnetic coupling with the resonant rod 2 at the through slot 12.

[0044] like Figure 2-Figure 4 As shown, in this embodiment, a long groove 13 is provided at the side wall of the through slot 12, and the long groove 13 and the through slot 12 are in a cross-shaped groove structure, one end of the plug-in portion 83 is plugged into the long groove 13, and the other end of the plug-in portion 83 is connected to the resonant cover plate 4. The long groove 13 has a positioning function, which facilitates the accurate installation of the mounting seat 8. At the same time, the long groove 13 can divide the through slot 12, reducing the leakage of the radio frequency signal at the through slot 12.

[0045] like Figure 2 and Figure 5 As shown, in this embodiment, a support body 61 is provided in the second mounting hole 831, and the conductor 6 is provided in the second mounting hole 831 through the support body 61, and the conductor 6 is provided coaxially with the second mounting hole 831. The function of the support body 61 is to realize the coaxial installation of the conductor 6 and the second mounting hole 831 to ensure the vertical connection between the conductor 6 and the connector 5, and the support body 61 can be made of plastic or rubber.

[0046] like Figure 2 and Figure 5 As shown, in this embodiment, the second mounting hole 831 is a countersunk hole, which is convenient for axially limiting the support body 61 and facilitating the installation of the support body 61.

[0047] like Figure 2 and Figure 6 As shown, in this embodiment, the port piece 7 includes a circular ring terminal 71 and a U-shaped portion 72 connected to the circular ring terminal 71, the U-shaped portion 72 includes a first folding piece 721, a connecting piece 722 and a second folding piece 723, the circular ring terminal 71 is connected to the first folding piece 721, the second folding piece 723 is connected to the conductor 6, and the circular ring terminal 71 is fixed to the outer surface of the plug-in portion 83 by a fastener 84. In this embodiment, the circular ring terminal 71 and the U-shaped portion 72 of the port piece 7 are integrally formed, and the port piece 7 is a copper sheet.

[0048] In this embodiment, the port piece 7 is used to achieve electromagnetic coupling with the resonant rod 2. The delay of the RF signal is changed by changing the width of the port piece 7, the length of the first folded piece 721 and the second folded piece 723, the width and length of the connecting piece 722, and the size of the external magnetic coupling, so that the delay can be adjusted to meet the needs of different products. In this embodiment, the structural dimensions of the connector 5, the conductor 6, the port piece 7 and the mounting seat 8 are stable, and the coupling amount between the port piece 7 and the resonant rod 2 is also very stable, thereby ensuring the consistency of the delay after the batch assembly of the filter, so that the port can be exempted from testing and the production efficiency is improved.

[0049] In this embodiment, the conductor 6 is integrally welded with the second folded piece 723. In other embodiments, the conductor 6 and the second folded piece 723 are integrally formed, that is, the conductor 6 and the port piece 7 are integrally formed, which further ensures the stability of the structure of the port piece 7 and the conductor 6 and ensures the stability of the filter performance.

[0050] like Figure 2 , Figure 3 ,and Figure 4 As shown, in this embodiment, the end face of the plug-in portion 83 inserted into the elongated groove 13 is in clearance with the bottom face of the elongated groove 13. In this embodiment, the clearance is 0.05mm-0.25mm. Since there will be errors in the production and processing of each part, the plug-in portion 83 and the elongated groove 13 are designed to be clearance-matched, that is, after the mounting seat 8 is assembled on the extension boss 9, the opening end face of the resonant cavity 1 is always higher than the end face of the plug-in portion 83 away from the extension platform, which is used to ensure that the resonant cover plate 4 can seal the opening, avoid the mounting seat 8 from interfering with the installation of the resonant cover plate 4, and ensure the shielding effectiveness. The gap setting gap is 0.05mm-0.25mm, which is used to reduce the impact of the gap on the shielding performance. By changing the height of the plug-in portion 83 and the depth of the elongated groove 13, the shielding effectiveness at the gap can meet the use requirements of the filter, and by changing the cross-sectional length of the plug-in portion 83, the path length of the gap can be changed, thereby achieving the effect of improving the shielding effectiveness.

[0051] In this embodiment, as 1 and Figure 4 As shown, the end surface of the plug-in portion 83 close to the resonance cover plate 4 is provided with a plurality of third mounting holes 832, and the resonance cover plate 4 is provided with a first threaded hole 41 coaxially arranged with the third mounting hole 832, and a fastener is screwed at the first threaded hole 41 and extends into the third mounting hole 832. The fastener is used to improve the firmness of the installation of the mounting seat 8 on the one hand, and to separate the gap and change the path of the gap on the other hand, so as to reduce the amount of RF signal leakage at the gap. In this embodiment, the plug-in portion 83 is provided with a fourth mounting hole 833, and the ring terminal 71 is threadedly connected to the fourth mounting hole 833 through a fastener and is arranged on the outer surface of the plug-in portion 83.

[0052] like Figure 5 As shown, a convex ring 812 is provided on one side of the flange 81 that is attached to the extended boss 9. The convex ring 812 contacts the surface of the extended boss 9, thereby reducing the contact area between the mounting seat 8 and the extended boss 9 to ensure the continuity of the assembled contact between the mounting seat 8 and the resonant cavity 1.

[0053] like Figure 2 and Figure 3 As shown, in this embodiment, a resonance platform 11 is provided in the resonance cavity 1, and the resonance rod 2 is provided on the resonance platform 11. Specifically, in this embodiment, a second threaded hole 111 is provided on the resonance platform 11, and the resonance rod 2 is screwed to the resonance platform 11 through the second threaded hole 111, so that it is convenient to adjust the position of the resonance rod 2. In this embodiment, the resonance platform 11 and the resonance cavity 1 are integrally formed. In other embodiments, the resonance rod 2 is directly fixed to the bottom of the resonance cavity 1, and can be specifically connected by welding or threading.

[0054] In this embodiment, if Figure 1 and Figure 3 As shown, four fifth mounting holes 811 are provided on the flange 81 , and the flange 81 is fixed to the extension boss 9 through the four fifth mounting holes 811 and the fasteners 84 , which facilitates the disassembly of the mounting seat 8 .

[0055] like Figure 1 and Figure 2 As shown, in this embodiment, the tuning screw 3 is fixed on the resonance cover plate 4 by means of a locking nut 31 . In other embodiments, the tuning screw 3 is a self-locking screw.

[0056] In this embodiment, the connector 5 is first threadedly installed in the first mounting hole 821, and the conductor 6 is installed in the support body 61. Then, the support body 61 is inserted into the second mounting hole 831 and one end of the conductor 6 is vertically contacted with the inner core of the connector 5, and then the conductor 6 is welded to the inner core of the connector 5; then, the port piece 7 is fixed to the outer surface of the plug-in portion 83 away from the mounting portion 82 by the fastener 84, and the other end of the conductor 6 is connected to the port piece 7, and then the conductor 6 and the port piece 7 are welded. The above operation process can be completed outside the resonant cavity 1, and does not need to occupy the resonant cavity 1. It is beneficial to reduce the size of the resonant cavity 1; then the plug-in portion 83 is inserted into the elongated groove 13, the flange 81 is fixed to the extended boss 9 with the fastener 84, and then the opening of the resonant cavity 1 is covered with the resonant cover plate 4, and the resonant cover plate 4 is connected to the plug-in portion 83 with the fastener 84, thereby completing the assembly of the filter. The assembly process is simple and convenient, and the structure of each part is simple and the dimensional accuracy is easy to control, so that the consistency of each part can be guaranteed, so that the performance of the mass-produced filter is stable and the quality is good, and each part occupies a small space, which is beneficial to the miniaturization of the filter.

[0057] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A filter, characterized in that: include: A resonant cavity, a resonant rod, a tuning screw, a resonant cover, a connector, a conductor, a port piece and a mounting seat, wherein the connector, the conductor and the port piece are all arranged on the mounting seat, and the two ends of the conductor are respectively vertically connected to the connector and the port piece, the resonant cavity is a frame structure with an opening on one side, the resonant rod is arranged in the resonant cavity, the resonant cover is arranged on the resonant cavity and seals the opening, the tuning screw is arranged on the resonant cover and extends into the resonant cavity, an extension boss is arranged on one side of the resonant cavity, a through groove is arranged on the side wall of the resonant cavity close to the extension boss, the mounting seat is arranged on the extension boss and electromagnetically couples the port piece with the resonant rod through the through groove, and the tuning screw and the plug-in surface of the connector are located on the same side; the mounting seat includes a method A flange, a mounting portion provided on the flange and a plug-in portion provided on the mounting portion, the mounting portion and the plug-in portion have length directions and are perpendicular to the flange, a first mounting hole is provided on the mounting portion, a second mounting hole is provided on the plug-in portion and is vertically connected to the first mounting hole, the connector is provided in the first mounting hole, the conductor is provided in the second mounting hole, the port piece is provided on the outer surface of the plug-in portion and is placed in the resonant cavity through the through slot; an elongated groove whose length direction is perpendicular to the length direction of the through slot is provided at the side wall of the through slot, one end of the plug-in portion is plugged into the elongated groove, and the other end of the plug-in portion is connected to the resonant cover plate; a support body is provided at the second mounting hole, the conductor is provided in the second mounting hole through the support body, and the conductor is coaxially arranged with the second mounting hole.

2. The filter according to claim 1, characterized in that: The second mounting hole is a countersunk hole.

3. The filter according to claim 1, characterized in that: The port piece includes a circular ring terminal and a U-shaped portion connected to the circular ring terminal, the U-shaped portion includes a first folding piece, a connecting piece and a second folding piece, the circular ring terminal is connected to the first folding piece, the second folding piece is connected to the conductor, and the circular ring terminal is fixed to the outer surface of the plug-in portion by a fastener.

4. The filter according to claim 3, characterized in that: The conductor and the second folded piece are integrally formed or welded.

5. The filter according to claim 1, characterized in that: The end surface of the plug-in portion inserted into the elongated groove is clearance-matched with the bottom surface of the elongated groove.

6. The filter according to claim 5, characterized in that: The plug-in portion is provided with a plurality of third mounting holes on the end surface close to the resonance cover plate, and the resonance cover plate is provided with a first threaded hole coaxially arranged with the third mounting holes, and a fastener is screwed at the first threaded hole and extends into the third mounting hole.

7. The filter according to any one of claims 1 to 6, characterized in that: A resonance platform is provided in the resonance cavity, and the resonance rod is provided on the resonance platform.

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