Cavity filter
By designing a recess on the cover plate of the cavity filter, the tuning screws pass through the cavity and hiding the exposed volume of the screws, the problem of large cavity filter volume and large resonator size is solved, and the space of the cavity filter is realized The reduction in utilization rate and cost is also ensured to the stability of the resonant frequency.
Patent Information
- Application Number
- CN202421015920.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-11
- Publication Date
- 2024-12-20
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing cavity filter is large in size, and the tuning screws protrude to occupy additional space. The contact surface requirements are high during installation and are not conducive to disassembly and adjustment. The resonator is expensive and has a large size, resulting in high costs.
The cover plate surface depression is designed, the tuning screw passes through the depression and enters the cavity, hides the exposed volume of the screw, reduces the cavity size, uses self-locking screws and elastic sleeves to improve fixing stability, reduces the size of the resonator to reduce costs.
The space utilization and tuning range of the cavity filter are increased, screw interference is avoided, the external size and cost of the cavity filter are reduced, and the stability of the resonant frequency is ensured.
Smart Images
Figure CN222214436U_ABST
Abstract
Description
Technical Field
[0001] Embodiments of the present disclosure relate to the field of communication technology, and in particular to a cavity filter. Background Art
[0002] The cavity filter is a filter with excellent performance, suitable for a variety of high-frequency and high-power occasions. It is mainly composed of a resonant cavity, a cover plate, a tuning screw and other components. When the input signal frequency of the cavity filter is close to the resonant frequency of the cavity, based on the resonance phenomenon of the cavity, the signal of this frequency will pass through losslessly, while the signals of other frequencies will be attenuated to achieve the filtering effect. The filtering effect mainly depends on the resonant frequency and bandwidth of the cavity, and these parameters can be achieved by adjusting the geometric dimensions of the cavity and the properties of the material. At present, the weight and volume of the cavity filter are relatively large. The tuning screws installed on the cover plate above the cavity filter take up additional space when protruding. The existing technology usually inserts all the tuning screws into the cover plate to reduce the volume occupancy, and has high requirements for the tightness of the contact surface between the tuning screw and the cover plate, and is not conducive to disassembly and adjustment. Utility Model Content
[0003] The embodiments of the present specification provide a cavity filter, aiming to solve one or more of the above problems and other potential problems.
[0004] In order to achieve the above objectives, the following technical solutions are provided:
[0005] The present specification provides a cavity filter, comprising a filter cavity, a cover plate arranged on the surface of the filter cavity, a tuning screw, and a resonator arranged in the filter cavity, wherein the surface of the cover plate is provided with a recessed portion, the recessed portion is recessed toward the inside of the filter cavity, and the bottom surface of the recessed portion is provided with a through hole; the screw rod of the tuning screw passes through the through hole and is aligned with the tuner, the end size of the tuning screw is smaller than the bottom size of the recessed portion and larger than the through hole size, and when the screw rod of the tuning screw passes through the through hole, the end of the tuning screw is stuck on the bottom surface of the recessed portion.
[0006] In a cavity filter in the embodiment of the present specification, the tuning screw passes through a recessed portion recessed toward the filter cavity and enters the filter cavity. On the one hand, the exposed volume of the tuning screw is hidden, the external size of the cavity filter is reduced, the space utilization and tuning range are increased, and the tuning screw is protected from external interference. On the other hand, the inner surface of the cover plate is protruding, the larger the bottom diameter of the recessed portion and the higher the side depth, the smaller the internal volume of the cavity filter. In order to ensure the original resonant frequency, the size of the resonator needs to be reduced. Since the resonator is expensive, the reduction in size also reduces costs.
[0007] In some embodiments, the height of the side surface of the recessed portion is greater than the height of the tuning screw exposed on the outer surface of the cover plate.
[0008] In some embodiments, the center of the bottom surface of the recessed portion is opposite to the center of the resonator, and the diameter of the bottom surface of the recessed portion is equal to or similar to the diameter of the resonator.
[0009] In some embodiments, the through hole is a threaded through hole, and the tuning screw is screwed into the filter cavity through the threaded through hole.
[0010] In some embodiments, the tuning screw is a self-locking screw.
[0011] In some embodiments, an elastic sleeve is provided on the side surface of the end of the tuning screw, and when the end of the tuning screw enters the recessed portion, the elastic sleeve fills the gap of the recessed portion.
[0012] In some embodiments, there are multiple recessed portions, multiple tuning screws and multiple resonators, multiple tuning screws pass through the recessed portions and correspond one-to-one to the resonators, and multiple resonators are respectively arranged in different resonant cavities of the filter cavity.
[0013] In some embodiments, different resonant cavities of the filter cavity are separated by isolation ribs, and two ends of the isolation ribs are respectively inserted into grooves on the bottom surface of the filter cavity and the inner surface of the cover plate.
[0014] In some embodiments, positioning posts are disposed at opposite corners of the inner surface of the cover plate, and positioning holes matching the positioning posts are disposed on the filter cavity.
[0015] In some embodiments, the recessed portion and the cover plate are an integrated structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other objects, features and advantages of the embodiments of the present specification will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present specification are shown by way of example and not limitation.
[0017] Figure 1 A side cross-sectional view of a cavity filter according to an embodiment of the present specification is shown;
[0018] Figure 2 Shows Figure 1 a side sectional view of the middle cover;
[0019] Figure 3 Shows Figure 1 Internal view of the middle cover;
[0020] Figure 4An external schematic diagram of a cavity filter according to an embodiment of this specification is shown;
[0021] Figure 5 A graph showing the relationship between the bottom diameter of the recessed portion and the resonant frequency of the cavity filter is shown;
[0022] Figure 6 A graph showing the relationship between the side depth of the recess and the resonant frequency of the cavity filter is shown.
[0023] 1-filter cavity, 11-isolation rib, 12-positioning hole, 2-cover plate, 21-recess, 211-through hole, 22-positioning column, 3-tuning screw, 4-resonator.
[0024] In the various drawings, the same or corresponding reference numerals represent the same or corresponding parts. DETAILED DESCRIPTION
[0025] The preferred embodiments of the present specification will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present specification are shown in the accompanying drawings, it should be understood that the present specification can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present specification more thorough and complete, and to fully convey the scope of the present specification to those skilled in the art.
[0026] The term "including" and its variations used in this document represent open inclusion, that is, "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "based at least in part on". The terms "an example embodiment" and "an embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one other embodiment". Terms such as "upper", "lower", "front", and "rear" indicating placement or positional relationships are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the principles of this specification, and do not indicate or imply that the referred elements must have a specific orientation, be constructed or operate in a specific orientation, and therefore should not be understood as limitations on this specification.
[0027] A cavity filter according to an embodiment of the present specification is described in detail below with reference to the accompanying drawings. Figure 1A side cross-sectional view of a cavity filter according to an embodiment of the specification is shown. The cavity filter according to the embodiment of the specification comprises a filter cavity 1, a cover plate 2 arranged on the surface of the filter cavity 1, a tuning screw 3, and a resonator 4 arranged in the filter cavity 1, a recess 21 is arranged on the surface of the cover plate 2, the recess 21 is recessed toward the inside of the filter cavity 1, and a through hole 211 is arranged on the bottom surface of the recess 21; the screw of the tuning screw 3 passes through the through hole 211 and is aligned with the resonator 4, the end size of the tuning screw 3 is smaller than the bottom size of the recess 21 and larger than the through hole 211, and when the screw of the tuning screw 3 passes through the through hole 211, the end of the tuning screw 3 is stuck on the bottom surface of the recess 21.
[0028] The tuning screw 3 is mainly used to accurately adjust the working frequency and performance of the cavity filter. By adjusting the position and depth of the tuning screw 3 passing through the cover plate 2, the resonant frequency and bandwidth of the cavity filter can be effectively changed, thereby achieving a filtering effect on a specific frequency signal. When the tuning screw 3 passes through the cover plate 2, it is usually necessary to fix the position and depth of the tuning screw 3 by a nut or the like. Therefore, the nut or other fixing structure protruding from the surface of the cover plate 2 occupies the space above the cavity filter cover plate, resulting in an increase in the overall volume of the filter and a waste of space. Under the same accommodation space, the adjustment range of the resonant frequency of the cavity filter becomes smaller. The tuning screw 3 of the embodiment of the present specification passes through the recessed portion 21, and the recessed portion 21 is recessed into the interior of the filter cavity 1, providing an accommodation space for the portion of the tuning screw 3 exposed to the outside, and the end of the tuning screw 3 is a nut or other fixed portion exposed to the outside. As Figure 1 As shown, Figure 1 The left side shows the state where the tuning screw 3 passes through the recess 21 and is aligned with the resonator 4. Figure 1 The right side shows a state where the tuning screw 3 has not yet penetrated into the recessed portion 21 .
[0029] In addition, such as Figure 2 , Figure 3 As shown, the side height of the recessed portion 21 is greater than the height of the tuning screw 3 exposed on the outer surface of the cover plate 2, and the bottom size of the recessed portion 21 is greater than the end size of the tuning screw 3, so that the end of the tuning screw 3 is fully accommodated, and a certain gap is left between the side of the recessed portion 21 and the end of the tuning screw 3, so as to facilitate the replacement of the tuning screw 3.
[0030] The recessed portion 21 of the embodiment of the present specification is recessed into the filter cavity 1, and the inner surface of the cover plate 2 is convex. Under the condition that other conditions remain unchanged, Figure 5 , Figure 6As shown, the larger the bottom diameter of the recessed portion 21 and the higher the side depth, the smaller the internal volume of the filter cavity 1 and the smaller the resonant frequency of the cavity filter. In order to ensure the original resonant frequency, it is necessary to reduce the height of the resonator 4 and change the size of the resonator 4. The resonator 4 is expensive. Reducing the size of the resonator 4 while ensuring the original resonant frequency indirectly achieves cost reduction.
[0031] Among them, the cover plate 2 is mainly made of metal materials, such as aluminum, copper, copper-aluminum alloy and other common materials, and its surface can be electroplated with a silver layer to improve the radio frequency characteristics of the cavity filter and improve the corrosion resistance and oxidation resistance of the cover plate 2 body. The recessed portion 21 and the cover plate 2 are an integrated structure, which is completed by integrated stamping, cold heading, stretching, or die-casting and other manufacturing processes to increase the overall structural stability of the cavity filter. The recessed portion 21 can also be a separate component, which is connected to the opening reserved on the cover plate 2 by welding, riveting, splicing and other processes, which is convenient for subsequent disassembly, replacement and maintenance. The through hole 211 is a threaded through hole, and the tuning screw 3 is screwed into the filter cavity 1 through the threaded through hole. The threaded through hole can also be set on other components and passed through the bottom surface of the recessed portion 21 by riveting, crimping and other processes.
[0032] In order to facilitate the tuning screw 3 passing through the recessed portion 21 to be aligned with the resonator 4, the center of the bottom surface of the recessed portion 21 is opposite to the center of the resonator 4, and the diameter of the bottom surface of the recessed portion 21 is equal to or similar to the diameter of the resonator 4, and the range of the bottom surface diameter of the recessed portion 21 is 80%-120% of the diameter of the resonator 4.
[0033] In one embodiment, the tuning screw 3 is a self-locking screw. The self-locking screw can automatically lock after being inserted or installed, providing a more stable fixing effect, preventing the screw from loosening under vibration or external force, and improving the reliability and safety of the connection; at the same time, it reduces the manual tightening process, improves efficiency and reduces labor costs, and ensures the quality and consistency of the cavity filter.
[0034] In another embodiment, an elastic sleeve is provided on the side of the end of the tuning screw 3. When the end of the tuning screw 3 enters the recessed portion 21, the elastic sleeve fills the gap of the recessed portion 21, thereby ensuring the fixing stability of the tuning screw 3 and the sealing of the contact between the tuning screw 3 and the cover plate 2.
[0035] In addition, if Figure 4As shown, there are multiple recessed parts 21, multiple tuning screws 3 and multiple resonators 4, and multiple tuning screws 3 pass through the recessed parts 21 and correspond to the resonators 4 one by one to adjust the resonant frequency of the cavity filter respectively. The multiple resonators 4 are respectively arranged in different resonant cavities of the filter cavity 1. The number of the resonant cavities is generally 6-13, not limited to Figure 4 Different resonant cavities of the filter cavity 1 are separated by isolation ribs 11, and the two ends of the isolation ribs 11 are respectively inserted into the grooves on the bottom surface of the filter cavity 1 and the inner surface of the cover plate 2, so that the isolation ribs 11 can be disassembled and assembled according to specific needs to change the number of the resonant cavities.
[0036] In order to increase the accuracy of the assembly process of the cover plate 2 and other components and prevent misalignment, positioning posts 22 are provided at the diagonals of the inner surface of the cover plate 2, and the filter cavity 1 is provided with positioning holes 12 matching the positioning posts 22. During assembly, the positioning posts 22 are aligned with the positioning holes 12 and inserted, and the relative positions of the cover plate 2 and other components of the cavity filter are limited.
[0037] Although several specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of this specification. Certain features described in the context of separate embodiments may also be implemented in a single implementation in combination. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination.
[0038] Although the subject matter has been described in language specific to structural features and / or methodological logical actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. On the contrary, the specific features and actions described above are merely example forms of implementing the claims.
[0039] The embodiments of the present specification have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.
Claims
1. A cavity filter, comprising a filter cavity (1), a cover plate (2) arranged on the surface of the filter cavity (1), a tuning screw (3), and a resonator (4) arranged in the filter cavity (1). It is characterized in that A recessed portion (21) is provided on the surface of the cover plate (2), the recessed portion (21) is recessed toward the inside of the filter cavity (1), and a through hole (211) is provided on the bottom surface of the recessed portion (21); a screw rod of the tuning screw (3) passes through the through hole (211) and is aligned with the resonator (4), the size of the end portion of the tuning screw (3) is smaller than the size of the bottom surface of the recessed portion (21) and larger than the size of the through hole (211), and when the screw rod of the tuning screw (3) passes through the through hole (211), the end portion of the tuning screw (3) is stuck on the bottom surface of the recessed portion (21).
2. The cavity filter according to claim 1, It is characterized in that The side height of the recessed portion (21) is greater than the height of the tuning screw (3) exposed on the outer surface of the cover plate (2).
3. The cavity filter according to claim 2, It is characterized in that The center of the bottom surface of the recessed portion (21) is opposite to the center of the resonator (4), and the diameter of the bottom surface of the recessed portion (21) is equal to or similar to the diameter of the resonator (4).
4. The cavity filter according to claim 3, It is characterized in that The through hole (211) is a threaded through hole, and the tuning screw (3) is screwed into the filter cavity (1) through the threaded through hole.
5. The cavity filter according to claim 4, It is characterized in that The tuning screw (3) is a self-locking screw.
6. The cavity filter according to claim 4, It is characterized in that An elastic sleeve is provided on the side surface of the end of the tuning screw (3); when the end of the tuning screw (3) enters the recessed portion (21), the elastic sleeve fills the gap in the recessed portion (21).
7. The cavity filter according to claim 1, It is characterized in that There are a plurality of recessed portions (21), and there are also a plurality of tuning screws (3) and a plurality of resonators (4); the plurality of tuning screws (3) respectively pass through the recessed portions (21) and correspond one-to-one with the resonators (4); and the plurality of resonators (4) are respectively arranged in different resonant cavities of the filter cavity (1).
8. The cavity filter according to claim 7, It is characterized in that Different resonant cavities of the filter cavity (1) are separated by isolation ribs (11), and two ends of the isolation ribs (11) are respectively inserted into grooves on the bottom surface of the filter cavity (1) and the inner surface of the cover plate (2).
9. The cavity filter according to claim 8, It is characterized in that Positioning posts (22) are provided at opposite corners of the inner surface of the cover plate (2), and positioning holes (12) matching the positioning posts (22) are provided on the filter cavity (1).
10. The cavity filter according to claim 1, It is characterized in that The recessed portion (21) and the cover plate (2) are an integrated structure.