CN221080315U

CN221080315U - Adjustable cavity filter

Info

Publication number: CN221080315U
Application number: CN202322322136.1U
Authority: CN
Inventors: 高红娟
Original assignee: Shenzhen Ante Wireless Equipment Co ltd
Current assignee: Shenzhen Ante Wireless Equipment Co ltd
Priority date: 2023-08-28
Filing date: 2023-08-28
Publication date: 2024-06-04
Anticipated expiration: 2033-08-28

Abstract

The utility model relates to the field of signal processing equipment, in particular to an adjustable cavity filter, a tuning bolt of the adjustable cavity filter is arranged in a resonant rod made of metal materials, the tuning bolt comprises a bolt body and a high polymer material medium coated outside the bolt body, the high polymer material medium is tightly combined with the bolt body to prevent the bolt body from loosening or falling off in the debugging process, and the high polymer material medium rotates along with the twisting of the tuning bolt so as to adjust the position of the tuning bolt in a resonant hole. The external thread is arranged outside the high polymer material medium, the high polymer material medium is arranged in the metal resonant rod and meshed with the internal thread of the metal resonant rod, and the high polymer material medium is meshed with the internal thread of the resonant rod by changing the deformation or adjustment of the tooth distance and the diameter change of the thread, so that the self-locking purpose is achieved.

Description

Adjustable cavity filter

Technical Field

The utility model relates to the field of signal processing equipment, in particular to an adjustable cavity filter.

Background

The filter is widely used as a frequency selection device in the communication field, especially in the radio frequency communication field, and in a base station for transmitting and receiving signals in a communication system, the filter is used for selecting communication signals and filtering clutter or interference signals outside the frequency of the communication signals. The cavity filter structure in the prior art generally comprises a cavity, a cover plate, a resonator arranged in the cavity, and a tuning screw rod or a screw corresponding to the resonator arranged on the cover plate through a lock nut, wherein the length of the tuning screw rod extending into the resonator is changed by rotating the tuning screw rod or the screw rod so as to realize electric tuning and filter performance.

However, the tuning mode of the cavity filter with the traditional structure adopts a threaded rotation fit mode, and a lock nut needs to be installed, so that the structure is complex, the weight of the product is large, and the cost is high. The installation of the tuning screw or the screw and the locking nut occupies a part of the overall height of the filter, which is unfavorable for reducing the overall height and volume of the product, and thus is unfavorable for the miniaturization design. A resonant cavity is usually formed between a cover plate and a cavity of the cavity filter, a tuning screw rod or a screw corresponding to the resonant tube is mounted on the cover plate through a fixing nut, and the length of the tuning screw rod or the screw extending into the resonant rod is changed by rotating the tuning screw rod or the screw rod, so that an electric tuning function is realized. However, because the structure needs to be provided with the fixing nut, the structure is complex, the product weight is large and the cost is high, and because the tuning screw rod or the screw is made of metal materials, the tuning is performed by being matched with the threads of the cover plate in a rotating way, and metal dust is easy to generate in the tuning process and falls into the resonant rod and the resonant cavity, particularly after the resonant rod and the resonant cavity are tuned for a plurality of times, the metal dust in the resonant rod and the resonant cavity can be gradually increased, and the metal dust can influence intermodulation performance required to be filtered, so that the performance of the cavity filter is influenced.

There is a need for a debug screw that is free of debug debris and reduces the height of the filter, and a filter using the same.

Disclosure of utility model

The utility model aims to solve the defects that the existing cavity filter is complex in structure and metal dust causes interference to a filtered signal, and provides an adjustable cavity filter.

The utility model discloses an adjustable cavity filter, which comprises a cavity with at least one resonant cavity and a metal cover plate covering the cavity, wherein at least one resonant rod is arranged in each resonant cavity, the resonant rod is provided with a resonant hole and a tuning bolt which is arranged in the resonant hole and is suspended and supported by the resonant rod, the tuning bolt and the metal cover plate are in direct contact with each other at a certain distance, a high polymer material medium is sleeved and attached on the outer periphery of the tuning bolt, and the high polymer material medium rotates along with the twisting of the tuning bolt so as to adjust the relative position of the tuning bolt in the resonant hole.

Preferably, the tuning bolt comprises a bolt body, a radial protrusion extending from the bolt body, and the polymer material medium is tightly buckled on the radial protrusion to prevent falling.

Preferably, the tuning bolt further comprises an axial protrusion extending from the bolt body, the axial protrusion preventing the polymer material medium from falling off in the axial direction.

Preferably, the tuning bolt comprises a first bolt body and a second bolt body, wherein the first bolt body is wrapped and sleeved by a high polymer material medium, the second bolt body is not directly contacted with the resonance rod, the diameter of the first bolt body is different from that of the second bolt body, and the outer diameter of the high polymer material medium is larger than that of the first bolt body or the second bolt body.

Preferably, the outer diameter surface of the high polymer material medium is provided with positioning lines.

Preferably, the inner surface of the resonant hole of the resonant rod is provided with internal threads, and the positioning threads of the high polymer material medium are external threads which can be meshed with the internal threads.

Preferably, a screw groove for tuning is formed at the end part of the tuning bolt.

Preferably, the cavity or the metal cover plate is provided with a tuning window communicated with the resonance hole.

Preferably, the dielectric constant of the polymer material medium is less than or equal to 5 under the test condition of 1 Ghz.

Preferably, the tuning bolt is a ceramic bolt, the dielectric constant of the tuning bolt is more than or equal to 15, and the dielectric loss tangent tg of the tuning bolt is less than or equal to 0.009 under the test condition of 1 GHz.

Preferably, the ceramic bolt has an umbrella-shaped structure, comprising a crown portion interposed between the metal cover plate and the resonant rod, and an umbrella stem portion of solid or hollow structure.

Preferably, the tuning window is further covered with a metal shielding layer for dust prevention and external interference prevention.

The tuning bolt of the adjustable cavity filter is arranged in the resonant rod made of metal. The tuning bolt comprises a bolt body and a high polymer material medium coated outside the bolt body, wherein the high polymer material medium is tightly combined with the bolt body to prevent the bolt body from loosening or falling off in the debugging process. The external thread is arranged outside the high polymer material medium, the high polymer material medium is arranged in the metal resonant rod and meshed with the internal thread of the metal resonant rod, and the high polymer material medium is meshed with the internal thread of the resonant rod through deformation or adjustment of thread pitch, so that the self-locking purpose is achieved.

Drawings

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

FIG. 2 is a schematic cross-sectional view of a first embodiment of a filter according to the present utility model;

FIG. 3 is a schematic cross-sectional view of another embodiment of the filter of the present utility model;

FIG. 4 is a schematic cross-sectional view of another embodiment of the filter of the present utility model;

FIG. 5 is a schematic cross-sectional view of another embodiment of the filter of the present utility model;

FIG. 6 is a schematic cross-sectional view of another embodiment of the filter of the present utility model;

Fig. 7 is a schematic sectional view of a portion a of the filter of the present utility model shown in fig. 6.

Detailed Description

The present utility model will be described in terms of various embodiments with reference to the accompanying drawings. In the following description, specific details are set forth such as the particular process, interfaces, techniques, etc. in order to provide a thorough understanding of the embodiments disclosed herein. However, it will be understood by those skilled in the art that the technology disclosed herein may be practiced in specific examples that depart from these specific details, and that a person of ordinary skill in the art will be able to practice the technology in various embodiments, which, even if not explicitly described or shown herein, nevertheless fall within the technology principles and are not beyond the spirit and scope thereof.

Referring to fig. 1 to 7, a tunable cavity filter 100 according to the present utility model includes a cover plate 10 made of metal materials such as aluminum, iron, copper, and alloys thereof by die casting, turning, and 3D printing techniques, wherein the cover plate 10 is used for sealing a metal cavity 20 of the cavity filter. The metal cavity 20 is generally divided into a plurality of resonant cavities 21, and a resonant rod 22 is set up in each resonant cavity 21. The resonance rod 22 is a cylindrical structure with a resonance hole 221 in a metal material, a tuning bolt 30 supported in a suspending manner is arranged in the resonance hole 221, the tuning bolt 30 and the metal cover plate 10 are in a certain distance and are not in direct contact with each other, a polymer material medium 40 is sleeved and attached on the outer periphery side of the tuning bolt 30, and the polymer material medium 40 can rotate along with the twisting of the tuning bolt 30 so as to adjust the position of the tuning bolt 30 in the resonance hole 221. When the resonant frequency of the resonant cavity 21 where the resonant rod 22 is located is adjusted, the tuning bolt 30 can be conveniently rotated, so that the high polymer material medium 40 connected with the tuning bolt 30 is caused to be displaced upwards or downwards in the resonant hole 221, the distance between the tuning bolt 30 and the inner wall opposite to the cover plate 10 is adjusted, and the capacitance value and the resonant frequency are adjusted.

In the process of adjusting the friction movement of the high polymer material medium 40 and the metal resonant rod 22, metal dust is not generated due to the material characteristics of the high polymer material medium 40, so that the filter intermodulation value is not deteriorated; and the tuning bolts 30 are arranged in the metal cavity 20, and the metal cover plate of the cavity filter 100 has a flat surface and meets the requirement of the installation size in a limited installation space.

In another embodiment, the tuning bolt 30 includes a bolt body 31, a radial protrusion 32 extending from the bolt body 31, and the polymer material medium 40 is tightly snapped onto the radial protrusion to prevent falling off. Similarly, the tuning bolt 30 further includes an axial protrusion (not identified) extending from the bolt body 31, which prevents the polymer material medium 40 from falling off in the axial direction. Even during the repeated adjustment of the tuning bolt 30, the polymer material medium 40 is displaced along with the movement of the bolt body 31. In addition to the above-mentioned fastening manner, the polymer material medium 40 is tightly adhered to the tuning bolt by means of adhesion. The polymer material medium 40 may fully and partially encapsulate the tuning bolt 30.

In another embodiment of the present invention, the tuning bolt 30 includes a first bolt body 301 wrapped and sleeved by the polymer material medium 40, and a second bolt body 302 not directly contacting the resonant rod 22, wherein the diameter of the first bolt body 301 is different from the diameter of the second bolt body 302, and the outer diameter of the polymer material medium 40 is larger than the diameter of the first bolt body 301 or the second bolt body 302, so that the tuning bolt 30 is suspended and supported in the resonant rod 22 by the polymer material medium 40 and is not contacted with the resonant rod 22. In other words, the tuning bolt 30 is air-gapped with the inner surface of the resonating rod 22. In other embodiments, the diameter of the first bolt 301 is smaller than that of the second bolt 302, and the polymer medium 40 is cylindrical and wraps the first bolt 301, so that the outer diameter of the polymer medium 40 sleeved on the tuning bolt 30 is larger than that of the second bolt 302, and an air gap is formed between the tuning bolt 30 and the inner surface of the resonant rod 22.

In this embodiment, the inner surface of the resonant hole 221 of the resonant rod 22 is provided with an internal thread 222, and the positioning thread of the polymer material medium 40 is an external thread 410 capable of being meshed with the internal thread.

In an embodiment of the present utility model, in order to facilitate twisting the tuning bolt 30, the end of the tuning bolt 30 is provided with a screw groove 33 for tuning, including but not limited to a straight groove, a cross groove, a hexagon groove, a plum blossom groove, etc. Further, a tuning window 11 is arranged on the cover plate of the filter corresponding to the metal resonance bolt, and a tool screwdriver is conveniently used to extend into the top screw groove 33 of the tuning bolt 30 in the cavity from the outside of the cover plate, so that the debugging purpose is achieved. Similarly, the tuning window 23 may be formed at the position of the metal cavity 20 corresponding to the resonant hole, so that the adjustment of the capacitance and the resonant frequency is more convenient no matter the cavity bottom or the metal cover plate of the filter faces to the direction.

In the embodiment of the present utility model, the polymer material medium 40 is selected from materials that satisfy both low dielectric constant and mechanical properties, electrical properties, and other factors, preferably have a dielectric constant of 5 or less, such as fluoroplastic, epoxy plastic, polypropylene resin, ABS plastic, and the like. The tuning bolt can be a ceramic bolt, the dielectric constant of the tuning bolt is more than or equal to 15, and the dielectric loss tangent tg is less than or equal to 0.009 under the test condition of 1 GHz. In addition, in order to precisely adjust the position of the tuning bolt 30, a moderate friction force is provided between the polymer material medium 40 and the resonant rod 22, and the outer diameter surface of the polymer material medium 40 is provided with positioning grains, which may be a frosted outer surface, or point-like protrusions, etc., so as to have a proper friction force with the inner surface of the resonant rod 22 to improve the mutual supporting state.

In other embodiments, the ceramic bolt 30 is in the form of an umbrella structure, including a crown portion between the metal cover plate and the resonant rod, and a stem portion of solid or hollow construction. Accordingly, the shape of the resonating posts 22 may also have resonating holes 221 with different apertures.

In this embodiment, a metal shielding layer made of aluminum foil may be laid on the upper side of the metal cover plate, that is, the tuning window is covered with a metal shielding layer 50 for dust prevention and external interference prevention.

According to the cavity filter 100, the damping cap made of the high polymer material is coated outside the debugging bolt 30, so that the influence of metal powder on the whole device is thoroughly avoided, and the debugging bolt 30 is arranged in the cavity, so that the whole filter is more convenient to install.

While specific embodiments of the utility model have been described above, it will be appreciated by those skilled in the art that these are by way of example only, and the scope of the utility model is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the principles and spirit of the utility model, but such changes and modifications fall within the scope of the utility model.

Claims

1. The utility model provides an adjustable cavity filter, includes the cavity that has at least one resonant cavity and covers the metal cover plate of cavity, at least one resonant rod is located in each resonant cavity, its characterized in that: the resonance rod is provided with a resonance hole and a tuning bolt which is arranged in the resonance hole and is supported by the resonance rod in a suspending way, the tuning bolt and the metal cover plate are not in direct contact with each other at a certain interval, a high polymer material medium is sleeved and attached on the outer periphery side of the tuning bolt, and the high polymer material medium rotates along with the twisting of the tuning bolt so as to adjust the relative position of the tuning bolt in the resonance hole.

2. The tunable cavity filter of claim 1, wherein: the tuning bolt comprises a bolt body, wherein a radial protruding part and/or an axial protruding part are/is derived and extends from the bolt body, and the high polymer material medium is tightly buckled on the radial protruding part or the axial protruding part to prevent falling.

3. A tunable cavity filter according to any one of claims 1 or 2, wherein: the tuning bolt comprises a first bolt body and a second bolt body, wherein the first bolt body is wrapped and sleeved by a high polymer material medium, the second bolt body is not directly contacted with the resonance rod, the diameter of the first bolt body is unequal to that of the second bolt body, the diameters of the first bolt body and the second bolt body are both smaller than the inner diameter of the resonance hole, and the outer diameter of the high polymer material medium is larger than the diameter of the first bolt body or the second bolt body.

4. The tunable cavity filter of claim 1, wherein: and positioning lines are arranged on the outer diameter surface of the high polymer material medium.

5. The tunable cavity filter of claim 4, wherein: the inner surface of the resonance hole of the resonance rod is provided with an internal thread, and the positioning threads of the high polymer material medium are external threads which can be meshed with the internal thread.

6. The tunable cavity filter of claim 1, wherein: the end part of the tuning bolt is provided with a screw groove for tuning.

7. A tunable cavity filter according to any one of claims 1 or 6, wherein: and the cavity or the metal cover plate is provided with a tuning window communicated with the resonance hole.

8. The tunable cavity filter of claim 1, wherein: the dielectric constant of the polymer material medium is less than or equal to 5.

9. A tunable cavity filter according to any one of claims 1 or 8, wherein: the tuning bolt is a ceramic bolt, the dielectric constant of the tuning bolt is more than or equal to 15, and the dielectric loss tangent tg is less than or equal to 0.009.

10. The tunable cavity filter of claim 9, wherein: the ceramic bolt is in an umbrella-shaped structure and comprises a crown-shaped part between the metal cover plate and the resonant rod and an umbrella handle part with a solid or hollow structure.