A filtering device and a coupling structure for a cavity filter

Abstract

This application discloses a filtering device and a coupling structure for a cavity filter. The coupling structure includes: a first coupling rod, the ends of which are respectively coupled to two adjacent cavity filters; and a second coupling rod, which is cross-coupled with the first coupling rod and grounded at both ends, such that the resonant frequency of the coupling structure is greater than the resonant frequency of the first coupling rod. Embodiments of this application provide a filtering device and a coupling structure for a cavity filter that, while meeting the required coupling requirements, increases the self-resonant frequency of the coupling structure, thereby increasing the distance between the resonant frequency of the coupling structure and the passband.

Description

Technical Field

[0001] The present invention relates to the field of communication technology, and in particular to a filtering device and a coupling structure for a cavity filter. Background Art

[0002] With the advancement of communication technology, base station systems are placing increasingly stringent demands on both near-end and far-end rejection in filters. Coupling rod structures are a well-established component in filters, meeting these high near-end rejection requirements. However, the coupling rod structure itself has a resonant frequency, determined by its structural dimensions.

[0003] Below 2 GHz, the coupling rod's own resonant frequency is usually higher than the filter's second harmonic, so its impact on the passband is not that significant. However, as the filter's operating frequency range falls to 3.5 GHz to 5 GHz, or even higher, the coupling rod's own resonant frequency gets closer and closer to the passband, resulting in an increasingly significant suppression effect on the near-end of the filter's passband.

[0004] The current common method is to improve the suppression degradation caused by the coupling rod's self-resonance by increasing the low-pass order. However, as the low-pass order increases, the most direct impact is the worsening of the filter's insertion loss. At the same time, as the low-pass order increases, machining errors accumulate, further affecting the filter's echo performance. This problem is more serious at high frequencies, affecting the filter's production pass rate and, in turn, its production cost.

[0005] As for the structure of the coupling rod itself, the current methods of increasing the coupling range of the coupling rod and adding structures to achieve negative coupling have little effect on solving the problem that the coupling rod's own resonant frequency is close to the passband. Summary of the Invention

[0006] The embodiments of the present application provide a filtering device and a coupling structure for a cavity filter, which, while meeting the coupling amount, improve the self-resonant frequency of the coupling structure to increase the distance between the resonant frequency of the coupling structure and the passband of the filtering device.

[0007] An embodiment of the present application provides a coupling structure for a cavity filter, comprising:

[0008] a first coupling rod, wherein two ends of the first coupling rod are respectively coupled with two adjacent cavity filters;

[0009] The second coupling rod is cross-coupled with the first coupling rod, and both ends of the second coupling rod are grounded, so that the resonant frequency of the coupling structure is greater than the resonant frequency of the first coupling rod.

[0010] In one embodiment, the second coupling rod forms a cross coupling within the first coupling rod.

[0011] In one embodiment, the first coupling rod comprises:

[0012] a first coupling body;

[0013] The second coupling portion is formed in the middle of the first coupling body. The second coupling portion has a through hole. The second coupling rod passes through the through hole and is perpendicular to the first coupling body.

[0014] In one embodiment, both ends of the second coupling rod are grounded.

[0015] In one embodiment, the second coupling rod does not contact the inner wall of the second coupling portion, and the second coupling rod is coaxial with the through hole.

[0016] In one embodiment, a cross-sectional shape of the second coupling rod is the same as or different from a shape of the through hole.

[0017] In one embodiment, an outer edge of the second coupling portion protrudes from an edge of the first coupling body.

[0018] In one embodiment, the first coupling rod comprises:

[0019] a first coupling body, the ends of which extend into one of the cavity filters respectively to couple two adjacent cavity filters;

[0020] A coupling portion extends from an end of the first coupling body into the cavity filter, and the coupling portion is parallel to the second coupling rod.

[0021] Another embodiment of the present application further provides a filtering device, comprising:

[0022] a plurality of cavity filters; and

[0023] The coupling structure as described above;

[0024] Each cavity filter has a coupling window communicating with an adjacent cavity filter, and the coupling structure is installed on the coupling window to couple the two adjacent cavity filters.

[0025] In one embodiment, each cavity filter comprises:

[0026] Metal housing; and

[0027] a resonant column, the resonant column being located in the metal shell;

[0028] The coupling structure is coupled with the resonant columns of two adjacent cavity filters;

[0029] Both ends of the second coupling rod are connected to the metal shell, and the first coupling rod is insulated from the metal shell.

[0030] The cross-coupling structure of this embodiment couples two adjacent cavity filters via a first coupling rod. The cross-coupling of the second coupling rod with the first, coupled with the simultaneous grounding of both ends of the second coupling rod, increases the resonant frequency of the entire coupling structure. This increase in the overall resonant frequency of the coupling structure distances it from the resonant frequencies of adjacent cavity filters, reducing the coupling structure's impact on the resonant device's passband. While maintaining cross-coupling requirements, it also improves near-end suppression of the resonant device's passband.

[0031] Compared with a coupling structure including only a first coupling rod, this embodiment cross-couples the first coupling rod through a second coupling rod with both ends grounded, thereby improving the overall resonant frequency of the cross-coupling structure.

[0032] Compared to existing methods that adjust the cross-coupling amount of the coupling rods and increase negative coupling, increasing the overall resonant frequency of the cross-coupling structure has a greater effect on near-end suppression of the resonant device's passband. Furthermore, the cross-coupling structure of this embodiment can be modified based on existing coupling structures, significantly reducing the production costs of the cross-coupling structure and the resonant device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0034] Figure 1 It is a structural schematic diagram of the coupling structure for the cavity filter of the present invention.

[0035] Figure 2a and Figure 2b It is a top view of the coupling structure for the cavity filter of the present invention.

[0036] Figure 3a and Figure 3b It is a structural schematic diagram and waveform diagram of the filtering device of the present invention.

[0037] Figure 4a and Figure 4b Schematic diagram and waveform diagram of a comparative example of the filtering device of the present invention. DETAILED DESCRIPTION

[0038] In order to better understand the above technical solutions, example embodiments of the present application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited to the exemplary embodiments described herein.

[0039] The embodiments of the present application provide a filtering device and a coupling structure for a cavity filter, which improve the self-resonant frequency of the coupling structure while meeting the coupling amount, so as to increase the distance between the resonant frequency of the coupling structure and the passband.

[0040] Figure 1 FIG. 1 is a schematic diagram of the coupling structure for the cavity filter of the present invention. Figure 1 As shown, an embodiment of the present invention provides a coupling structure 1 for a cavity filter, wherein the coupling structure 1 includes:

[0041] A first coupling rod 10, where both ends of the first coupling rod 10 are respectively coupled to two adjacent cavity filters 100;

[0042] The second coupling rod 20 is cross-coupled with the first coupling rod 10 , and both ends of the second coupling rod 20 are grounded, so that the resonant frequency of the coupling structure 1 is greater than the resonant frequency of the first coupling rod 10 .

[0043] In this embodiment, a cavity filter 100 (see Figure 3a ) to form a coupling between adjacent cavity filters and provide high near-end suppression. The distance between the resonant frequency of the coupling structure 1 and the resonant frequency of the adjacent cavity filter 100 determines the near-end suppression effect of the filter device's passband.

[0044] The cross-coupling structure of this embodiment couples two adjacent cavity filters 100 via a first coupling rod 10. The cross-coupling of the second coupling rod 20 with the first coupling rod 10, coupled with the simultaneous grounding of both ends of the second coupling rod 20, increases the resonant frequency of the entire coupling structure. This increase in the overall resonant frequency of the coupling structure 1 increases the distance from the resonant frequency of the adjacent cavity filter 100, thereby reducing the coupling structure's impact on the resonant device's passband. While maintaining cross-coupling requirements, it also improves near-end suppression of the resonant device's passband.

[0045] Compared with a coupling structure including only a first coupling rod, this embodiment cross-couples the first coupling rod through a second coupling rod with both ends grounded, thereby improving the overall resonant frequency of the cross-coupling structure.

[0046] Compared to existing methods that adjust the cross-coupling amount of the coupling rods and increase negative coupling, increasing the overall resonant frequency of the cross-coupling structure has a greater effect on near-end suppression of the resonant device's passband. Furthermore, the cross-coupling structure of this embodiment can be modified based on existing coupling structures, significantly reducing the production costs of the cross-coupling structure and the resonant device.

[0047] Among them, Figure 1 As shown, the second coupling rod 20 forms a cross coupling in the first coupling rod 10. That is, the intersection position of the second coupling rod 20 and the first coupling rod 10 is located inside the first coupling rod 10, not outside the first coupling rod 10.

[0048] Specifically, the first coupling rod 10 includes:

[0049] A first coupling body 11;

[0050] The second coupling portion 21 is formed in the middle of the first coupling body 11 . The second coupling portion 21 has a through hole 22 therethrough. The second coupling rod 20 passes through the through hole 22 and is perpendicular to the first coupling body 11 .

[0051] In this embodiment, the first coupling body 11 may be formed in a sheet shape, and a through hole 22 is provided in the middle thereof for the second coupling rod 20 to pass through. The second coupling rod 20 is inserted into the through hole 22 and does not come into contact with the first coupling body 11.

[0052] Taking the case where the first coupling rod 10 extends horizontally and the second coupling rod 20 extends vertically as an example, the lengths of the second coupling rod 20 above and below the first coupling rod 10 determine the resonant frequency of the coupling structure 1. The intersection of the second coupling rod 20 and the first coupling rod 10 can be located at the midpoint of the second coupling rod 20, or the lengths of the second coupling rod 20 above and below the first coupling rod 10 can be different.

[0053] The spacing between the second coupling rod 20 and the inner wall of the through hole 22 determines the cross-coupling amount of the coupling structure 1. In a preferred embodiment, the second coupling rod 20 is coaxial with the through hole 22 to achieve the same direction and amount in all directions. Of course, the second coupling rod 20 can also be non-coaxial with the through hole 22, as long as it maintains a spacing from the first coupling rod 10.

[0054] Specifically, the cross-sectional shape of the second coupling rod 20 is the same as or different from the shape of the through hole 22 .

[0055] In e.g. Figure 1 and Figure 2aIn the embodiment shown, the through hole 22 is square in shape, and the cross-section of the second coupling rod 20 is also square. The second coupling rod 20 is coaxial with the through hole 22, but can have the same or different angles. For example, the second coupling rod 20 can be oriented in the same direction as the through hole 22, so that the spacing between the second coupling rod 20 and the first coupling rod 10 is the same in all directions. Alternatively, Figure 2a As shown, the second coupling rod 20 can have an angular orientation with respect to the through hole 22 with a rotation angle difference of, for example, 45°, and the spacing between the second coupling rod 20 and the first coupling rod 10 in various directions can be formed to be different, thereby achieving adjustment of the cross-coupling amount of the coupling structure 1.

[0056] Alternatively, as Figure 2b In the embodiment shown, the through hole 22 is square in shape, and the cross-sectional shape of the second coupling rod 20 can be circular, hexagonal, or triangular, etc. Such an arrangement can also be used to adjust the cross-coupling amount of the coupling structure 1 .

[0057] In a specific embodiment, the second coupling portion 21 is formed in the middle of the first coupling body 11 and is integrally formed with the first coupling body 11 , and is mainly used to form a through hole 22 for cross-coupling with the second coupling rod 20 .

[0058] The edge of the second coupling portion 21 can coincide with the edge of the first coupling body 11, meaning that the first coupling rod 10 forms a linear, continuous structure along its length. Alternatively, the outer edge of the second coupling portion 21 can protrude beyond the edge of the first coupling body 11, forming a shape that is thicker in the middle and narrower at both ends along its length. The second coupling portion 21, which protrudes beyond the edge of the first coupling body 11, can internally define a through-hole 22 with a diameter greater than the width of the first coupling body 11, thereby expanding the adjustable range of the cross-coupling degree.

[0059] In this embodiment, the cross-coupling amount of the coupling structure 1 can be adjusted by adjusting multiple factors such as the size of the second coupling portion 21, the size of the through hole 22, the shape of the through hole 22, the cross-sectional shape of the second coupling rod 20, the spacing between the second coupling rod 20 and the first coupling rod 10, and the angle. A wider range of adjustment can be achieved by combining various factors, thereby being applicable to a wider range of uses.

[0060] like Figure 1 As shown, the first coupling rod 10 includes:

[0061] The first coupling body 11 has its ends respectively extending into one cavity filter 100 to couple two adjacent cavity filters 100;

[0062] The first coupling portion 12 extends from an end of the first coupling body 11 into the cavity filter 100 , and the first coupling portion 12 is parallel to the second coupling rod 20 .

[0063] The length of the first coupling portion 12 may correspond to the coupling amount between the coupling structure 1 and the cavity filter 100. For example, an increase in the length of the first coupling portion 12 may correspond to an increase in the coupling amount.

[0064] See also Figure 3a Another embodiment of the present invention provides a filtering device, comprising:

[0065] a plurality of cavity filters 100; and

[0066] like Figures 1 to 2b Any one of the coupling structures 1 shown in ;

[0067] Each cavity filter 100 has a coupling window 110 communicating with an adjacent cavity filter 100 . The coupling structure 1 is installed in the coupling window 110 to couple the two adjacent cavity filters 100 .

[0068] As described above, the cross-coupling structure of this embodiment achieves coupling between two adjacent cavity filters 100 via the first coupling rod 10. Furthermore, the cross-coupling of the second coupling rod 20 with the first coupling rod 10, coupled with the simultaneous grounding of both ends of the second coupling rod 20, increases the resonant frequency of the entire coupling structure. This increase in the overall resonant frequency of the coupling structure 1 increases the distance from the resonant frequency of the adjacent cavity filter 100, thereby reducing the coupling structure's impact on the resonant device's passband. While maintaining a sufficient cross-coupling threshold, this structure also improves near-end suppression of the resonant device's passband.

[0069] Figure 4a A schematic structural diagram of a comparative example of the filter device of the present invention is shown in FIG. Figure 4a As shown, the filter device of the comparative example has a cross-coupling structure, which is connected to Figure 3a The first coupling rods 10 in the coupling structure 1 shown form a cross coupling.

[0070] in, Figure 3a and Figure 4a The illustrated embodiment employs consistent parameters as shown in Table 1.

[0071] Table 1 Filter device parameters

[0072]

[0073] By comparison Figure 3b and Figure 4b It can be seen that Figure 3aThe resonant frequency of the coupling structure 1 in the embodiment shown is 4736 MHz, and Figure 4a The resonant frequency of the cross-coupling structure in the embodiment shown is 4468 MHz, from which it can be seen that Figure 3a In the embodiment shown, the resonant frequency of the coupling structure 1 is increased by 268 MHz.

[0074] Specifically, if Figure 3a As shown, each cavity filter 100 includes:

[0075] Metal housing 111; and

[0076] The resonant column 112 is located in the metal housing 111;

[0077] The coupling structure 1 is coupled to the resonant columns 112 of two adjacent cavity filters 100 ;

[0078] Both ends of the second coupling rod 20 are connected to the metal shell 111 to achieve grounding, and the first coupling rod 10 is insulated from the metal shell 111 .

[0079] The metal shells 111 on the surfaces of adjacent cavity filters 100 are connected at the location of the coupling window 110, and both ends of the second coupling rod 20 can be electrically connected to the metal shell 111 at the location of the coupling window 110. The first coupling rod 10 can be supported at the location of the coupling window 110 by a dielectric support member, such as plastic, to achieve insulation isolation from the metal shell 111.

[0080] Therefore, further, the coupling amount of the coupling structure 1 can be achieved by setting the window size of the coupling window 110 and then setting the length of the second coupling rod 20 .

[0081] The cross-coupling structure of this embodiment couples two adjacent cavity filters via a first coupling rod. The cross-coupling of the second coupling rod with the first, coupled with the simultaneous grounding of both ends of the second coupling rod, increases the resonant frequency of the entire coupling structure. This increase in the overall resonant frequency of the coupling structure distances it from the resonant frequencies of adjacent cavity filters, reducing the coupling structure's impact on the resonant device's passband. While maintaining cross-coupling requirements, it also improves near-end suppression of the resonant device's passband.

[0082] Compared with a coupling structure including only a first coupling rod, this embodiment cross-couples the first coupling rod through a second coupling rod with both ends grounded, thereby improving the overall resonant frequency of the cross-coupling structure.

[0083] Compared to existing methods that adjust the cross-coupling amount of the coupling rods and increase negative coupling, increasing the overall resonant frequency of the cross-coupling structure has a greater effect on near-end suppression of the resonant device's passband. Furthermore, the cross-coupling structure of this embodiment can be modified based on existing coupling structures, significantly reducing the production costs of the cross-coupling structure and the resonant device.

[0084] The above describes the basic principles of the present application in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations. It cannot be considered that these advantages, strengths, effects, etc. are required for each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and facilitation of understanding, not for limitation. The above details do not limit the present application to the specific details that must be used to implement the present application.

[0085] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0086] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0087] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0088] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize that certain variations, modifications, alterations, additions, and sub-combinations thereof are intended to be within the scope of the present invention.

Claims

1. A coupling structure (1) for a cavity filter (100), characterized in that: include: a first coupling rod (10), wherein two ends of the first coupling rod (10) are respectively coupled to two adjacent cavity filters (100); A second coupling rod (20) is cross-coupled with the first coupling rod (10), and both ends of the second coupling rod (20) are grounded, so that the resonant frequency of the coupling structure (1) is greater than the resonant frequency of the first coupling rod (10).

2. The coupling structure (1) according to claim 1, characterized in that The second coupling rod (20) forms a cross coupling in the first coupling rod (10).

3. The coupling structure (1) according to claim 2, characterized in that The first coupling rod (10) comprises: A first coupling body (11); A second coupling portion (21), the second coupling portion (21) is formed in the middle of the first coupling body (11), the second coupling portion (21) has a through hole (22) therethrough, the second coupling rod (20) passes through the through hole (22) and is perpendicular to the first coupling body (11).

4. The coupling structure (1) according to any one of claims 1 to 3, characterized in that: The resonant frequency of the coupling structure (1) is related to the length of the second coupling rod (20).

5. The coupling structure (1) according to claim 3, characterized in that The second coupling rod (20) does not contact the inner wall of the second coupling portion (21), and the second coupling rod (20) is coaxial with the through hole (22).

6. The coupling structure (1) according to claim 3, characterized in that The cross-sectional shape of the second coupling rod (20) is the same as or different from the shape of the through hole (22).

7. The coupling structure (1) according to claim 3, characterized in that The outer edge of the second coupling portion (21) protrudes from the edge of the first coupling body (11).

8. The coupling structure (1) according to claim 3, characterized in that The first coupling rod (10) comprises: A first coupling body (11), the ends of which respectively extend into one of the cavity filters (100) to couple two adjacent cavity filters (100); A first coupling portion (12), the first coupling portion (12) extends from an end of the first coupling body (11) into the cavity filter (100), and the first coupling portion (12) is parallel to the second coupling rod (20).

9. A filtering device, characterized in that: include: a plurality of cavity filters (100); and The coupling structure (1) according to any one of claims 1 to 8; Each cavity filter (100) has a coupling window (110) communicating with an adjacent cavity filter (100), and the coupling structure (1) is mounted on the coupling window (110) to couple the two adjacent cavity filters (100).

10. The filtering device according to claim 9, wherein Each cavity filter (100) comprises: a metal housing (111); and a resonant column (112), the resonant column (112) being located inside the metal shell (111); The coupling structure (1) is coupled to the resonant columns (112) of two adjacent cavity filters (100); Both ends of the second coupling rod (20) are connected to the metal shell (111), and the first coupling rod (10) is insulated and isolated from the metal shell (111).

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