Cavity filter

Abstract

The utility model provides a cavity filter. The cavity comprises a cavity body and a cover plate which covers an opening of the cavity body in a welding manner; a mounting column is arranged at the bottom of the cavity, resonators are fixedly arranged in the mounting column, capacitive coupling pieces are clamped between the bottoms of part of the resonators and the mounting column, the free ends of the capacitive coupling pieces extend towards the space between the two adjacent resonators, and through holes are formed in the capacitive coupling pieces; the adjusting screw is rotationally arranged on the cover plate, a screw rod of the adjusting screw extends into the cavity, the depth of the screw rod in the cavity is adjustable, the screw rod of the adjusting screw is opposite to the through hole, and the screw rod can penetrate through the through hole. According to the cavity filter provided by the invention, the capacitance coupling value adjusting range is relatively large.

Description

Technical Field

[0001] This application belongs to the field of communication technologies, and more specifically, relates to a cavity filter. Background Art

[0002] Existing filters generally include a capacitive coupling device, which is used to form filter capacitance transmission zeros / poles, enabling the filter to obtain a narrower transition bandwidth and very small stopband ripple. The capacitive coupling device in existing filters generally includes a resonator, a flybar, a support base for clamping the flybar, and a capacitive coupling adjustment screw. The capacitive coupling adjustment screw extends into the support base, and the capacitance coupling value is adjusted by adjusting the distance between the capacitive coupling adjustment screw and the flybar.

[0003] Generally, the support base is machined from polytetrafluoroethylene or other engineering plastics with a dielectric constant greater than 2 and assembled in the side wall of the filter cavity. As a result, the support base isolates 80% of the capacitance formed by the capacitive coupling adjustment screw and the flybar, resulting in a capacitance coupling device with a numerical adjustment range of only 20%, thereby reducing the performance of the filter. Summary of the Utility Model

[0004] The purpose of the embodiments of this application is to provide a cavity filter to solve the technical problem of too small a numerical adjustment range of capacitive coupling in the existing technology.

[0005] To achieve the above purpose, the technical solution adopted in the embodiments of this application is to provide a cavity filter, which includes:

[0006] A cavity and a cover plate welded to cover the opening of the cavity;

[0007] Installation posts are provided at the bottom of the cavity, a resonator is fixedly arranged in the installation posts, a capacitive coupling sheet is clamped between the bottom of part of the resonator and the installation posts, the free end of the capacitive coupling sheet extends into the space between two adjacent resonators, and a through hole is provided on the capacitive coupling sheet;

[0008] An adjustment screw is rotatably arranged on the cover plate, the screw rod of the adjustment screw extends into the cavity and the depth in the cavity can be adjusted, the screw rod of the adjustment screw is directly opposite to the through hole and the screw rod can pass through the through hole.

[0009] Optionally, the axis of the through hole on the capacitive coupling sheet is located at the midpoint of the distance between two adjacent resonators.

[0010] Optionally, the capacitive coupling sheet is bent and formed with a convex section, and the through hole is arranged in the middle of the convex section.

[0011] Optionally, the resonator is columnar with a wall thickness, and includes a funnel-shaped top and a tubular middle. An installation hole for passing through a bolt is formed inside the resonator. The bolt passes through the installation hole to fix the resonator to the installation post. The side wall of the head of the bolt abuts against the inclined inner wall of the resonator, and the rod portion of the bolt abuts against the inner wall of the middle part of the resonator.

[0012] Optionally, a flanging structure is formed around the opening edge of the top of the resonator.

[0013] Optionally, both the resonator and the capacitive coupling sheet are formed by stamping a plate-shaped metal sheet.

[0014] Optionally, a reinforcing rib is connected between two adjacent installation posts. The bottom of the reinforcing rib is connected to the bottom of the cavity, and the cavity, the installation posts and the reinforcing rib are integrally formed.

[0015] The cavity filter provided by the embodiment of the present application has at least the following beneficial effects:

[0016] By clamping the capacitive coupling sheet between the installation post and the resonator, and at the same time providing a through hole on the capacitive coupling sheet and passing an adjusting screw through the through hole of the capacitive coupling sheet. In this way, on the one hand, the assembly connection of the capacitive coupling sheet in the cavity does not need to use polytetrafluoroethylene or other engineering plastics with a dielectric constant greater than 2, so as to avoid the problem that the capacitance adjustment value range is affected. On the other hand, the capacitive coupling sheet is directly clamped between the installation post and the resonator, which can reduce the number of components inside the cavity filter and simplify the structure for easy production, assembly and debugging. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a sectional view of the cavity filter in some embodiments of the present application;

[0019] Figure 2 It is an assembled sectional view of the resonator and the capacitive coupling sheet in some embodiments of the present application;

[0020] Figure 3 It is a top view of a partial structure of the cavity filter in some embodiments of the present application. Detailed Embodiments

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the following further details this application in conjunction with the accompanying drawings and embodiments.

[0022] It should be understood that the specific embodiments described herein are merely used to explain this application and are not used to limit this application.

[0023] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element.

[0024] When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this application and simplifying the description, rather than indicating or implying 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 construed as a limitation to this application.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0027] In the description of this application, "a plurality of" means two or more unless otherwise specifically defined.

[0028] Please refer to Figures 1 to 3 together, and now the cavity filter provided by the embodiments of this application will be described.

[0029] Referring to Figure 1 , it can be understood that the cavity filter described in this application includes a cavity 100 and a cover plate 200 welded and covered at the opening of the cavity 100. Among them, the cavity 100 can be formed by die-casting process or by 3D printing process, and the specific is not limited thereto.

[0030] At the bottom of the cavity 100, there is an integrally formed mounting post 300. A resonator 400 is fixedly arranged on each mounting post 300. Among them, in the resonance combination formed by some adjacent two resonators 400, a capacitive coupling sheet 500 is clamped between the bottom of one resonator 400 and the mounting post 300. A through hole 510 is opened on the capacitive coupling sheet 500. The capacitive coupling sheet 500 extends towards the space between two adjacent resonators 400 in the same resonance combination. That is, in the orthographic projection plane, the projection of the capacitive coupling sheet 500 coincides with the projection of the line connecting the axes of two adjacent resonators 400.

[0031] The adjusting screw 600 is rotatably arranged on the cover plate 200. The screw rod of the adjusting screw 600 extends into the cavity 100 and its depth in the cavity 100 can be adjusted. The screw rod of the adjusting screw 600 is directly opposite to the through hole 510 and the screw rod can pass through the through hole 510. When adjusting the capacitive coupling value of the cavity filter, by screwing the adjusting screw 600 to change the distance between its screw rod and the capacitive coupling sheet 500, or changing the depth of the screw rod passing through the through hole 510 on the capacitive coupling sheet 500.

[0032] By arranging the capacitive coupling sheet 500, the resonator 400 and the adjusting screw 600 as follows: on the one hand, the capacitive coupling sheet 500 is clamped between the mounting post 300 and the resonator 400. There is no need to set polytetrafluoroethylene or other engineering plastics with a dielectric constant greater than 2 on the cavity 100 to fix the capacitive coupling sheet 500, thus avoiding the problem that the capacitance adjustment value range is affected and effectively increasing the adjustment of the capacitive coupling value of the cavity filter; on the other hand, also because the capacitive coupling sheet 500 is clamped between the mounting post 300 and the resonator 400, the capacitive coupling sheet 500 does not need an additional connection structure to be fixed inside the cavity 100, thus simplifying the number of components inside the cavity 100 and facilitating the production, assembly and debugging of the cavity filter; on the third hand, a through hole 510 is arranged on the capacitive coupling sheet 500 and the adjusting screw 600 can be arranged in the through hole 510 of the capacitive coupling sheet 500, making the adjustable range of its extension length inside the filter cavity 100 larger, that is, the adjustable range of the capacitive coupling value of the cavity filter is larger, thus effectively improving the performance of the cavity filter.

[0033] Reference Figure 1 and Figure 2 In some specific embodiments, with reference to

[0034] In some specific embodiments, the capacitive coupling sheet 500 is bent and formed with a convex section 520, and the through hole 510 is disposed in the middle of the convex section 520. By providing the convex section 520, the setting depth of the capacitive coupling sheet 500 in the cavity 100 can be highly compensated, so that the depth adjustment range of the adjusting screw 600 in the through hole 510 is larger, thereby meeting the requirements of the capacitive coupling adjustment value range.

[0035] Reference Figure 2 , in some embodiments, the resonator 400 is columnar with a wall thickness. The resonator 400 includes a funnel-shaped top and a tubular middle. An installation hole 410 for passing through a bolt is formed inside the resonator 400; the bolt passes through the installation hole 410 to fix the resonator 400 to the installation column 300. The side wall of the head of the bolt abuts against the inclined inner wall of the resonator 400, and the rod portion of the bolt abuts against the inner side wall of the middle of the resonator 400. By setting the resonator 400 in this way, when the bolt fixes the resonator 400 to the installation column 300, the contact area between the bolt and the inner side wall of the resonator 400 is larger, thereby enhancing the connection stability of the resonator 400 on the installation column 300.

[0036] Reference Figure 2 , further, a flanging structure 420 is formed around the opening edge of the funnel shape at the top of the resonator 400, and the aforementioned capacitive coupling sheet 500 is formed on the flanging structure 420 of the resonator 400.

[0037] Based on the above embodiments, the resonator 400 is formed by stamping a plate-shaped metal.

[0038] Reference Figure 3 , based on the above embodiments, a reinforcing rib 700 is connected between two adjacent installation columns 300. The bottom of the reinforcing rib 700 is connected to the bottom of the cavity 100, and the cavity 100, the installation column 300, and the reinforcing rib 700 are integrally formed. By forming the reinforcing rib 700 at the bottom of the cavity, the structural strength of each installation column 300 is relatively large, and the position of the resonator 400 can be ensured to be stable when installing the resonator 400, thereby effectively improving the performance stability of the filter.

[0039] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A cavity filter, characterized in that, Comprising: a cavity and a cover plate welded to the opening of the cavity; mounting posts are arranged at the bottom of the cavity, resonators are fixedly arranged in the mounting posts, a capacitive coupling sheet is clamped between the bottom of part of the resonators and the mounting posts, the free end of the capacitive coupling sheet extends into the space between two adjacent resonators, and through holes are formed in the capacitive coupling sheet; an adjusting screw rotatably arranged on the cover plate, the screw rod of the adjusting screw extends into the cavity and the depth in the cavity can be adjusted, the screw rod of the adjusting screw is directly opposite to the through hole and the screw rod can pass through the through hole.

2. The cavity filter according to claim 1, wherein: The axis of the through hole on the capacitive coupling sheet is located at the midpoint of the distance between two adjacent resonators.

3. The cavity filter according to claim 2, wherein: The capacitive coupling sheet is bent and formed with a convex section, and the through hole is arranged in the middle of the convex section.

4. The cavity filter according to any one of claims 1 to 3, characterized in that: The resonator is columnar with a wall thickness, the resonator includes a funnel-shaped top and a tubular middle part, and an installation hole for passing through a bolt is formed inside the resonator; the bolt passes through the installation hole to fix the resonator to the mounting post, the side wall of the head of the bolt abuts against the inclined inner wall of the resonator, and the rod part of the bolt abuts against the inner wall of the middle part of the resonator.

5. The cavity filter according to claim 4, wherein: A flanging structure is formed around the opening edge of the top of the resonator.

6. The cavity filter according to claim 1, wherein: Both the resonator and the capacitive coupling sheet are formed by stamping a plate-shaped metal sheet.

7. The cavity filter according to claim 1, characterized in that: Reinforcing ribs are connected between two adjacent mounting posts, the bottom of the reinforcing ribs is connected to the bottom of the cavity, and the cavity, the mounting posts and the reinforcing ribs are integrally formed.

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