CN220122078U - Filter - Google Patents

Abstract

The utility model provides a filter, which comprises a cavity, a resonant rod arranged in the cavity and a cover plate covering an opening of the cavity, wherein the resonant rod is arranged in the cavity; the resonance rod comprises a resonance disc which is opposite to the cover plate, the filter further comprises a disc expansion structure, the disc expansion structure comprises a disc expansion piece, the disc expansion piece is movably arranged above the resonance disc, and the disc expansion piece can be driven to move above the resonance disc and extend out of the resonance disc for different lengths, so that the area of the resonance disc opposite to the cover plate is increased. According to the utility model, the extension disc pieces extend out of the resonance disc for different lengths, so that the area of the resonance disc, which is opposite to the cover plate, is increased, the opposite area is adjustable, the tuning frequency is adjusted, the installation of a tuning screw on the cover plate can be avoided, the processing technology of the cover plate is simplified, the weight of the cover plate is reduced, and the assembly efficiency of the cover plate is improved; in addition, the expansion plate piece is arranged in the cavity, so that extra height space of the filter is not occupied.

Description

Filter

Technical Field

The utility model belongs to the technical field of communication, and particularly relates to a filter.

Background

Filters are widely used as a frequency selective device in the field of communications, particularly radio frequency communications. In the base station, the filter is used for selecting the communication signal and filtering clutter or interference signals outside the frequency of the communication signal. The filter generally comprises a cavity, a resonant rod arranged in the cavity and a cover plate covering the opening of the cavity, wherein a tuning screw is arranged on the cover plate, and the distance between the tuning screw and the resonant rod is adjusted by rotating the tuning screw, so that the purpose of adjusting the resonant frequency is achieved. However, the tuning screw is limited in height, so that the design space of the filter is limited, and meanwhile, the tuning screw is required to be installed by machining a threaded hole in the cover plate, so that the machining cost of the cover plate is increased, the weight of the cover plate is increased, and the risk that metal scraps fall into the cavity is also easy to occur.

Disclosure of Invention

The embodiment of the utility model aims to provide a filter so as to solve the technical problems that in the prior art, the resonant frequency is regulated by a tuning screw, so that the limit is high, the cost is increased and the risk that metal scraps fall into a cavity exists.

In order to achieve the above purpose, the utility model adopts the following technical scheme: providing a filter, comprising a cavity, a resonant rod arranged in the cavity and a cover plate covering the top opening of the cavity; the resonant rod comprises a resonant disc which is opposite to the cover plate, the filter further comprises a disc expansion structure, the disc expansion structure comprises a disc expansion piece, the disc expansion piece is movably arranged above the resonant disc, and the disc expansion piece can be driven to move above the resonant disc and extend out of the resonant disc for different lengths so as to enlarge the area of the resonant disc opposite to the cover plate.

In one possible design, a through hole is formed in the center of the resonant disk, the expansion disk member is movably arranged on the resonant disk, and the expansion disk member can be driven to gradually extend from the resonant disk to the position of the through hole or gradually retract from the position of the through hole to the resonant disk.

In one possible design, the expansion disc member is movably disposed on the resonator plate, and the expansion disc member can be driven to gradually extend from the resonator plate to the outer edge of the resonator plate or gradually retract from the outer edge of the resonator plate to the resonator plate.

In one possible design, the resonant disc is further provided with a rotating shaft, the disc-expanding member is eccentrically sleeved on the rotating shaft, and the disc-expanding member can be driven to swing around the rotating shaft so as to gradually extend out of the resonant disc or gradually retract back onto the resonant disc.

In one possible design, the resonator plate is provided with a plurality of expansion plates, each expansion plate is distributed at intervals along the circumferential direction of the resonator plate, and each expansion plate can be driven to gradually extend from the resonator plate to the position of the through hole or gradually retract from the position of the through hole to the resonator plate.

In one possible design, the disc-expanding structure further includes a driving member movably disposed on the resonant disc, the driving member is respectively connected with each of the disc-expanding members, and the driving member can be driven to move so as to drive each of the disc-expanding members to move synchronously on the resonant disc.

In one possible design, the driving member is annular, each of the expansion disc members is disposed on the inner side of the driving member, a connecting rod is connected between the expansion disc member and the driving member, one end of the connecting rod is hinged to the expansion disc member, the other end of the connecting rod is hinged to the driving member, and the driving member can drive each of the expansion disc members to swing on the resonance disc through each of the connecting rods after being pushed to rotate.

In one possible design, the driving member is formed with a driving portion for being matched with an external tool, and the cover plate is formed with an adjusting hole for the external tool to extend into the cavity at a position corresponding to the driving portion.

In one possible design, the expansion plate member is provided with a first bonding surface and a second bonding surface which are oppositely arranged, and one end of the first bonding surface and one end of the second bonding surface are converged into a tip; when the tips of the expansion disc pieces are converged at the circle center of the through hole, the first bonding surface of the expansion disc piece is bonded with the second bonding surface of the adjacent expansion disc piece, the second bonding surface of the expansion disc piece is bonded with the first bonding surface of the adjacent expansion disc piece, and the expansion disc pieces are enclosed to form a circle.

In one possible design, the driving member is formed with a guide groove extending along the circumferential direction of the driving member, and the resonant disk is provided with a guide rod slidably engaged with the guide groove to guide and limit the rotation of the driving member.

The filter provided by the utility model has the beneficial effects that: according to the filter provided by the embodiment of the utility model, the expanding disc piece is arranged on the resonant disc, the expanding disc piece can be driven to move above the resonant disc, and the expanding disc piece can extend out of the resonant disc for different lengths, so that the area of the resonant disc opposite to the cover plate can be increased, the area of the resonant disc opposite to the cover plate can be adjusted, and according to a resonant frequency formula of the filter, when the area of the resonant disc opposite to the cover plate is changed, the resonant frequency is correspondingly changed, namely, the adjustment of the resonant frequency can be realized by adjusting the area of the resonant disc opposite to the cover plate. Meanwhile, the disc expanding piece is arranged above the resonance disc, so that the installation of structures such as tuning screws on the cover plate is avoided, the processing technology of the cover plate is simplified, the production cost of the cover plate is reduced, the processing efficiency of the cover plate is improved, the weight of the cover plate is reduced, and the assembly efficiency of the cover plate is improved. In addition, the expansion plate piece is arranged in the cavity, space limitation is not needed to be considered, the temperature drift passing rate of the product is improved under certain conditions, the market competitiveness of the product is improved, and the attractiveness of the product is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic perspective view of a filter according to an embodiment of the present utility model;

fig. 2 is a schematic longitudinal section of a filter according to an embodiment of the present utility model;

FIG. 3 is an enlarged schematic view of a portion of FIG. 2A;

FIG. 4 is a schematic structural diagram of the resonant disk and the disk expanding structure in FIG. 2;

fig. 5 is a schematic view of the structure of the stent of fig. 4.

Wherein, each reference sign in the figure:

100. a cavity; 200. a resonant rod; 210. a resonant disk; 211. a through hole; 300. a cover plate; 310. an adjustment aperture; 400. a spread-spectrum disk structure; 410. a disc-expanding member; 411. a first bonding surface; 412. a second bonding surface; 413. a peripheral surface; 420. a driving member; 421. a guide groove; 422. a driving section; 430. a connecting rod; 440. a rotating shaft; 450. a guide rod.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be 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 be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the utility model.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present utility model, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

Referring to fig. 1 to 4, a filter according to an embodiment of the present utility model will be described.

The filter comprises a cavity 100, a resonant rod 200 arranged in the cavity 100 and a cover plate 300 covering an opening of the cavity 100; the resonance rod 200 includes a resonance plate 210 disposed opposite to the cover plate 300, the filter further includes a diffusion plate structure 400, the diffusion plate structure 400 includes a diffusion plate 410, the diffusion plate 410 is movably disposed above the resonance plate 210, and the diffusion plate 410 can be driven to move above the resonance plate 210 and extend out of the resonance plate 210 for different lengths, so as to increase the area of the resonance plate 210 opposite to the cover plate 300.

Taking fig. 4 as an example, the resonant disk 210 is in a ring shape, and when the disk expanding member 410 is not arranged on the resonant disk 210, the area of the resonant disk 210 opposite to the cover plate 300 is the whole area of the resonant disk 210; when the expansion plate 410 is disposed on the resonator plate 210, the larger the outwardly protruding length of the expansion plate 410, the more the resonator plate 210 faces the cover plate 300, and the smaller the outwardly protruding length of the expansion plate 410, the less the area of the resonator plate 210 faces the cover plate 300. The expansion plate 410 can be driven to move above the resonant disk 210, so that the expansion plate 410 can extend out of the resonant disk 210 for different lengths, thus the area of the resonant disk 210 opposite to the cover plate 300 can be adjusted, and according to the resonant frequency formula of the filter, when the area of the resonant disk 210 opposite to the cover plate 300 is changed, the resonant frequency is correspondingly changed, that is, the adjustment of the resonant frequency can be realized by adjusting the area of the resonant disk 210 opposite to the cover plate 300.

Alternatively, the expansion disc 410 may be movably disposed directly on the resonator plate 210, and the expansion disc 410 is mounted and supported by the resonator plate 210. It will be appreciated that in other embodiments of the present utility model, the diffuser 410 may be supported above the resonator plate 210 by other support structures, which are not limited in this regard.

In general, the utility model performs frequency modulation by arranging the disc expander 410 above the resonance disc 210, thereby replacing the structure of installing tuning screws and the like on the cover plate 300 to perform frequency modulation, simplifying the processing technology of the cover plate 300, reducing the production cost of the cover plate 300, improving the processing efficiency of the cover plate 300, reducing the weight of the cover plate 300 and improving the assembly efficiency of the cover plate 300. In addition, the expansion plate 410 is arranged in the cavity 100, so that space limitation is not needed to be considered, the temperature drift passing rate of the product is improved under certain conditions, the market competitiveness of the product is improved, and the attractiveness of the product is improved.

The utility model can extend into the tool from the upper part of the cover plate 300 through the cover plate 300 to drive the expansion plate 410 to move when frequency modulation is carried out, and can withdraw the tool when frequency modulation is not needed, so that the utility model does not occupy too much height space.

In one embodiment, referring to fig. 3 and 4, a through hole 211 is formed in the center of the resonator plate 210, and a spreader 410 is movably disposed on the resonator plate 210, where the spreader 410 can be driven to gradually extend from the resonator plate 210 to the position of the through hole 211 or gradually retract from the position of the through hole 211 to the resonator plate 210.

Specifically, referring to fig. 4, in the initial state, the expansion disc 410 is disposed on the resonator disc 210, and if the length of the expansion disc 410 extending outwards relative to the resonator disc 210 is the smallest, the facing area between the resonator disc 210 and the cover plate 300 is the smallest; when the expansion plate 410 is driven to extend from the resonator plate 210 to the position of the through hole 211, the expansion plate area of the expansion plate 410 to the resonator plate 210 increases gradually, and the facing area of the resonator plate 210 and the cover plate 300 increases gradually. In contrast, when the diffusion member 410 is gradually withdrawn from the position of the through hole 211 onto the resonator plate 210, the diffusion area of the diffusion member 410 to the resonator plate 210 is gradually reduced, and the facing area of the resonator plate 210 and the cover plate 300 is gradually reduced.

In summary, the present utility model adjusts the expansion area of the expansion plate 410 to the resonator plate 210 by reciprocating the expansion plate 410 to the through hole 211, thereby realizing the bidirectional frequency adjustment.

In another embodiment of the present utility model, the expansion member 410 may also be configured to provide different degrees of shielding to the resonator plate 210 by extending the expansion member 410 gradually toward the outer edge of the resonator plate 210 or retracting the expansion member gradually from the outer edge of the resonator plate 210 toward the resonator plate 210, without limitation.

In one embodiment, referring to fig. 3 and 4, the resonator plate 210 is further provided with a rotating shaft 440, and the expansion plate 410 is eccentrically sleeved on the rotating shaft 440, and the expansion plate 410 can be driven to swing around the rotating shaft 440 to gradually extend out of the resonator plate 210 or gradually retract back onto the resonator plate 210.

Specifically, referring to fig. 4, the rotating shaft 440 is vertically installed on the resonator plate 210, and the expansion plate 410 is eccentrically rotatably sleeved on the rotating shaft 440, and when the expansion plate 410 is pushed, the expansion plate 410 swings around the rotating shaft 440, so that the expansion plate 410 gradually extends out of the resonator plate 210 or gradually retreats back to the resonator plate 210. It will be appreciated that in other embodiments of the present utility model, the expansion member 410 may be slidably disposed on the resonator plate 210, and in particular, the expansion member 410 may be driven by an external tool to slide on the resonator plate 210, such that the expansion member 410 slides gradually out of the resonator plate 210 or slides gradually back into the resonator plate 210, which is not limited herein.

In one embodiment, referring to fig. 4, a plurality of expansion plates 410 are disposed on the resonator plate 210, wherein the expansion plates 410 are distributed at intervals along the circumferential direction of the resonator plate 210, and each expansion plate 410 can be driven to move on the resonator plate 210 to gradually extend from the resonator plate 210 to the position of the through hole 211 or gradually retract from the position of the through hole 211 to the resonator plate 210, so as to expand the area of the resonator plate 210 to different degrees. In this embodiment, the areas of the resonator plates 210 are respectively expanded by a plurality of expansion plates 410 distributed along the circumferential direction of the resonator plates 210, so that the areas of the resonator plates 210 opposite to the cover plate 300 are uniformly distributed along the circumferential direction of the resonator plates 210, the tuning frequencies are uniformly distributed, and the tuning frequencies are tuned.

Alternatively, the respective diffusion plates 410 are equally spaced apart in the circumferential direction of the resonator plate 210, and are each disposed close to the through hole 211. Specifically, the expansion disc members 410 may be configured to have the same structural shape, and the rotating shafts 440 corresponding to the expansion disc members 410 are distributed in a circular shape, so that when the expansion disc members 410 swing synchronously, the areas of the expansion disc members 410 extending out of the resonant disc 210 at any time are equal.

In an embodiment, referring to fig. 3 and 4, the disc expanding structure 400 further includes a driving member 420, the driving member 420 is movably disposed on the resonator disc 210, the driving member 420 is respectively connected to each of the disc expanding members 410, and the driving member 420 can be driven to move so as to drive each of the disc expanding members 410 to synchronously move on the resonator disc 210. In this embodiment, each of the expansion disc members 410 can be driven to move synchronously by one driving member 420, which can save the number of the driving members 420, simplify the structure and save the cost on one hand, and can make each of the expansion disc members 410 move synchronously and enter and exit synchronously on the other hand, so that the areas of the resonant disc 210 at any moment are uniformly distributed along the circumferential direction, and the frequency modulation is more accurate. It should be understood that in other embodiments of the present utility model, a driving member 420 may be provided corresponding to each of the expansion members 410, and then each expansion member 410 may be separately driven to move by each driving member 420, which is not limited herein.

In one embodiment, referring to fig. 4, the driving member 420 is annular, each of the expansion members 410 is disposed on the inner side of the driving member 420, a connecting rod 430 is connected between the expansion members 410 and the driving member 420, one end of the connecting rod 430 is hinged to the expansion members 410, the other end of the connecting rod 430 is hinged to the driving member 420, and the driving member 420 can drive each of the expansion members 410 to swing on the resonant disk 210 through each of the connecting rods 430 after being pushed to rotate.

Specifically, when the driving member 420 is driven to rotate, one end of each link 430 rotates following the driving member 420, and since the length of the link 430 is not changed, the other end of the link 430 is pulled in the opposite direction to the rotation of the driving member 420, thereby pulling the dial 410 to rotate the dial 410 around the rotation shaft 440. The arrangement of the connecting rod 430 enables the spreader 410 and the driving member 420 to be both attached to the resonator plate 210 in a planar manner, and the spreader 410 and the driving member 420 do not need to be stacked to be hinged.

It should be understood that in other embodiments of the present utility model, the link 430 may not be provided, and each of the expansion members 410 may be directly hinged to the driving member 420, and when the driving member 420 rotates, the expansion members 410 may be driven to swing.

In one embodiment, referring to fig. 4, a driving part 422 is formed on the driving member 420, and the driving part 422 is used for being matched with an external tool, so that the external tool can drive the driving member 420 to rotate through the driving part 422.

Specifically, referring to fig. 4, the driving portion 422 has a cylindrical structure protruding from the upper surface of the driving member 420, and the driving member 420 can be driven to rotate by pushing the driving portion 422 by sleeving an external tool on the driving portion 422.

In one embodiment, referring to fig. 1, an adjusting hole 310 is formed on the cover plate 300 corresponding to the driving portion 422, and an external tool may extend into the cavity 100 through the adjusting hole 310 to cooperate with the driving portion 422, so as to drive the driving member 420.

In one embodiment, referring to fig. 5, the tray 410 has a first bonding surface 411 and a second bonding surface 412 disposed opposite to each other, and one end of the first bonding surface 411 and one end of the second bonding surface 412 converge into a tip; when the tip of each expansion disc 410 converges at the center of the through hole 211, the first bonding surface 411 of the expansion disc 410 is bonded to the second bonding surface 412 of the adjacent expansion disc 410, the second bonding surface 412 of the expansion disc 410 is bonded to the first bonding surface 411 of the adjacent expansion disc 410, and each expansion disc 410 is enclosed to form a circle.

Specifically, when the driving member 420 is pushed to rotate, the driving members 420 drive the expansion disc members 410 to swing on the resonant disc 210, and when the tip end of each expansion disc member 410 just swings to the center position of the through hole 211, the expansion disc members 410 are sequentially attached to form a circle along the circumferential direction, specifically, the first attaching surface 411 of the expansion disc member 410 is attached to the second attaching surface 412 of the previous expansion disc member 410, the second attaching surface 412 of the expansion disc member 410 is attached to the first attaching surface 411 of the next expansion disc member 410, and finally the whole through hole 211 is covered, and at this time, the area of the resonant disc 210 facing the cover plate 300 is the largest.

Optionally, the first abutting surface 411 is a concave arc surface, and the second abutting surface 412 is a convex arc surface. Alternatively, the first bonding surface 411 is a convex arc surface, and the second bonding surface 412 is a concave arc surface.

Optionally, the expanding disc member 410 further includes a peripheral surface 413, the peripheral surface 413 is an arc surface, and the peripheral surface 413 is connected between the first bonding surface 411 and the second bonding surface 412, when the expanding disc members 410 are bonded end to end, the peripheral surface 413 of the expanding disc member 410 just encloses to form a circle, so that the expanding disc members 410 enclose to form a circle.

Alternatively, referring to fig. 5, the stent 410 has a substantially fan shape, it will be appreciated that in other embodiments of the present utility model, the stent 410 may have other shapes, such as a strip shape or a polygon having four sides or more, which is not limited only herein.

In one embodiment, referring to fig. 3 and 4, the driving member 420 is formed with one or more guiding grooves 421 extending along the circumferential direction of the driving member 420, and the resonator plate 210 is provided with one or more guiding rods 450, and the guiding rods 450 and the guiding grooves 421 are slidably matched to guide and limit the rotation of the driving member 420.

Specifically, the guide rod 450 is fixedly disposed, and when the driving member 420 rotates, the guide groove 421 rotates along with the driving member 420, and the guide rod 450 cooperates with different positions of the guide groove 421 during rotation of the guide groove 421, thereby guiding rotation of the driving member 420. Meanwhile, when the guide rod 450 abuts against opposite ends of the guide groove 421, the driving member 420 cannot rotate, so that the rotation stroke of the driving member 420 can be limited.

Optionally, referring to fig. 4, a plurality of guide grooves 421 distributed along the circumferential direction of the driving member 420 may be provided, and a guide rod 450 is provided on the resonator plate 210 corresponding to each guide groove 421, where each guide rod 450 is in one-to-one guide fit with each guide groove 421, so as to ensure the rotation stability of the driving member 420.

In one embodiment, the driving member 420 is stacked with a mounting plate, which is a transparent member, and the guide rod 450 is disposed through the guide slot 421, and opposite ends of the guide rod 450 are respectively fixed to the resonator plate 210 and the mounting plate. Specifically, the resonant disk 210 is formed with a first mounting groove, the mounting plate is formed with a second mounting groove, and opposite ends of the guide rod 450 are respectively mounted in the first mounting groove and the second mounting groove. In this embodiment, the transparent plate is disposed on the driving member 420, so that the opposite ends of the guide rod 450 are firmly fixed, so that the guide rod 450 is stable to guide the driving member 420, and meanwhile, the mounting plate also has a limiting effect on the driving member 420, so that the driving member 420 rotates stably on the resonant disk 210, and the situation of detachment from the resonant disk 210 does not occur. In addition, the transparent arrangement of the mounting plate allows the mounting plate to not affect the shielding effect of the spread-spectrum structure 400.

In another embodiment of the present utility model, the driving member 420 may be supported by the first support provided on the outer circumference of the resonator plate 210, so that the driving member 420 may not only drive the diffuser 410, but also prevent the driving member 420 from shielding the resonator plate 210, thereby avoiding interference between the driving member 420 and the cover plate 300 or having an additional influence on the resonant frequency.

In another embodiment of the present utility model, the expansion plate 410 may be movably disposed on a second support other than the resonant disk 210, the expansion plate 410 is supported by the second support, and then the expansion plate 410 is driven to move on the second support, so as to adjust the area of the expansion plate 410 extending into the resonant disk 210, thereby achieving the purpose of adjusting the area of the resonant disk 210 facing the cover plate 300.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.

Claims (10)

1. The filter is characterized by comprising a cavity, a resonant rod arranged in the cavity and a cover plate covering an opening of the cavity; the resonant rod comprises a resonant disc which is opposite to the cover plate, the filter further comprises a disc expansion structure, the disc expansion structure comprises a disc expansion piece, the disc expansion piece is movably arranged above the resonant disc, and the disc expansion piece can be driven to move above the resonant disc and extend out of the resonant disc for different lengths so as to enlarge the area of the resonant disc opposite to the cover plate.

2. The filter of claim 1, wherein a through hole is formed in the center of the resonator plate, the expansion plate is movably provided on the resonator plate, and the expansion plate can be driven to gradually protrude from the resonator plate toward the through hole position or gradually retract from the through hole position to the resonator plate.

3. The filter of claim 1 wherein said expansion element is movably disposed on said resonator plate, said expansion element being capable of being driven to extend progressively from said resonator plate toward an outer edge of said resonator plate or to retract progressively from said outer edge of said resonator plate back onto said resonator plate.

4. The filter of claim 1, wherein the resonator plate is further provided with a rotating shaft, the expansion plate member is eccentrically sleeved on the rotating shaft, and the expansion plate member can be driven to swing around the rotating shaft to gradually extend out of the resonator plate or gradually retract back onto the resonator plate.

5. A filter according to claim 2, wherein a plurality of expansion discs are provided on the resonator plate, each of the expansion discs being spaced apart circumferentially of the resonator plate, each of the expansion discs being capable of being driven to extend progressively from the resonator plate to the through hole location or retract progressively from the through hole location onto the resonator plate.

6. The filter of claim 5, wherein the disc-spreading structure further comprises driving members movably disposed on the resonator disc, the driving members being respectively connected to the disc-spreading members, the driving members being capable of being driven to move so as to drive the disc-spreading members to move synchronously on the resonator disc.

7. The filter of claim 6, wherein the driving member is ring-shaped, each of the expansion plates is disposed on an inner side of the driving member, a connecting rod is connected between the expansion plate and the driving member, one end of the connecting rod is hinged to the expansion plate, the other end of the connecting rod is hinged to the driving member, and the driving member can drive each of the expansion plates to swing on the resonance plate through each of the connecting rods after being pushed to rotate.

8. The filter of claim 7, wherein the driving member is formed with a driving portion for engaging with an external tool, and the cover plate is formed with an adjustment hole for the external tool to extend into the cavity at a position corresponding to the driving portion.

9. The filter of claim 7, wherein the diffuser has a first abutment surface and a second abutment surface disposed opposite each other, one end of the first abutment surface converging into a tip with one end of the second abutment surface; when the tips of the expansion disc pieces are converged at the circle center of the through hole, the first bonding surface of the expansion disc piece is bonded with the second bonding surface of the adjacent expansion disc piece, the second bonding surface of the expansion disc piece is bonded with the first bonding surface of the adjacent expansion disc piece, and the expansion disc pieces are enclosed to form a circle.

10. The filter of claim 7, wherein the driving member is formed with a guide groove extending along a circumferential direction of the driving member, and the resonator plate is provided with a guide bar slidably engaged with the guide groove to guide and limit rotation of the driving member.