Filter

Abstract

The utility model discloses a filter, which relates to the technical field of filters, and is characterized by comprising a body, a capacitive coupling connecting sheet and three resonators in linear arrangement are arranged in the cavity, and a tuning cavity is arranged in the cavity. The tuning cavities located in the resonator parts at the two ends are used for being connected with the two ends of the capacitive coupling connecting piece, the resonator located at one end is connected with a capacitive coupling stand column, and a capacitive coupling side column connected with the inner side wall of the cavity is arranged in the tuning cavity matched with the resonator at the other end. Metal screws which are in threaded connection with the corresponding capacitive coupling stand columns and the capacitive coupling side columns are inserted into the two ends of the capacitive coupling connecting pieces. According to the utility model, the connection structure of the capacitive coupling connection sheet is optimized, and the metal screw is adopted to replace a plastic screw to connect and fix the capacitive coupling connection sheet and the cavity, so that the difficulty of realizing the capacitive coupling zero point is reduced, and the effects of reducing the cost and the assembly difficulty are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of filters, and more specifically to a filter. Background Art

[0002] A filter is a frequency filtering device that selects signals in the required frequency band and suppresses signals in the unnecessary frequency band. Filters are widely used in RF, microwave and other communication fields. Currently, the most widely used filter in RF and microwave bands is the coaxial cavity filter. The coaxial cavity filter has good electromagnetic shielding, compact structure, and low passband insertion loss. In the case of capacitive loading, the volume of the coaxial cavity filter can be made very small, and it has the advantages of high rectangular coefficient and high power capacity.

[0003] A Chinese patent with announcement number CN208062223U discloses a filter transmission zero point realization structure, which includes a cavity; a cover plate covering the cavity; a first resonator, a second resonator and a third resonator arranged in the cavity and arranged in sequence, wherein the first resonator, the second resonator and the third resonator are arranged in a straight line along the length direction of the cavity; and a coupling connecting piece fixed in the cavity and distributed along the length direction of the cavity, wherein the total length of the coupling connecting piece is less than half of the input frequency wavelength and less than the spacing between the first resonator and the third resonator, and the two ends of the coupling connecting piece are respectively fixed to the bottom of the cavity, wherein the coupling connecting piece includes a first coupling portion, a connecting portion bent and extended by the first coupling portion, and a second coupling portion extending from the connecting portion in the opposite direction to the first coupling portion, wherein the first coupling portion and the second coupling portion are arranged at intervals from each other to form a capacitor, and the first resonator and the third resonator are cross-coupled by the capacitor to form a capacitive transmission zero point.

[0004] However, the two ends of the coupling connecting plate in the transmission zero point realization structure of the filter are respectively close to the first resonator and the third resonator, and one end needs to be fixed with a plastic gasket and a plastic screw. In addition, since the transmission zero point realization structure of the filter needs to have the characteristics of long-term high temperature resistance, the performance requirements of the plastic gasket and the plastic screw are relatively high, so when special plastics are used, it will lead to increased costs. In addition, when fixing the coupling connecting plate, it is necessary to avoid damage caused by excessive torque, which needs to be improved. Summary of the invention

[0005] In view of this, the purpose of this application is to provide a filter to achieve the purpose of reducing costs and assembly difficulty. The specific scheme is as follows:

[0006] A filter comprises a cavity, wherein a capacitive coupling connecting piece and three linearly arranged resonators are arranged in the cavity, wherein a tuning cavity is arranged in the cavity, wherein the tuning cavity in the resonator parts at both ends is used to connect with both ends of the capacitive coupling connecting piece, and the resonator at one end is connected with a capacitive coupling column, and the tuning cavity matching the resonator at the other end is provided with a capacitive coupling side column connected with the inner side wall of the cavity, and both ends of the capacitive coupling connecting piece are plugged with metal screws threadedly connected with the corresponding capacitive coupling column and the capacitive coupling side column.

[0007] Preferably, three fixing columns are provided in the tuning cavity and are matched and connected with the corresponding resonators respectively, and the resonator is provided with fixing screws which are inserted from top to bottom into the corresponding fixing columns and are connected with the inner threads.

[0008] Preferably, the capacitive coupling column is connected with a capacitive coupling adjustment position, and the capacitive coupling adjustment position is integrally formed with the corresponding fixing column.

[0009] Preferably, a cover plate is provided at the top of the cavity, and three frequency tuning screws are inserted into the cover plate, which are matched with the corresponding resonators and inserted into the corresponding upper openings of the resonators.

[0010] Preferably, a coupling tuning screw is inserted between two adjacent frequency tuning screws, and both the frequency tuning screw and the coupling tuning screw are threadedly connected with nuts abutting against the outer plate of the cover plate.

[0011] Preferably: the capacitive coupling connecting piece includes a connecting transverse portion and an upper bending portion connected to the connecting transverse portion, and the connecting transverse portion is used to connect to the capacitive coupling column, the upper bending portion is used to connect to the capacitive coupling side column, and the connecting transverse portion is provided with a transfer arc portion.

[0012] It can be seen from the above scheme that the present application provides a filter, which has the following beneficial effects: by optimizing the connection structure of the capacitive coupling connecting piece, metal screws are used instead of plastic screws to connect and fix the capacitive coupling connecting piece and the cavity, so as to reduce the difficulty of achieving the capacitive coupling zero point, which has the effect of reducing the cost and the difficulty of assembly; at the same time, in the development direction of multiplexed filters, the purpose of reducing the external dimensions of the filter and avoiding the occasional zero point that is difficult to achieve due to the linear cavity arrangement is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of this embodiment;

[0014] Figure 2 It is a schematic cross-sectional structural diagram of this embodiment.

[0015] Explanation of the reference numerals in the accompanying drawings: 1. Cavity; 11. Tuning cavity; 12. Capacitive coupling side column; 13. Capacitive coupling column; 14. Capacitive coupling adjustment position; 15. Fixed column; 2. Cover plate; 3. Frequency tuning screw; 4. Coupling tuning screw; 5. Resonator; 6. Fixing screw; 7. Capacitive coupling connecting piece; 71. Connecting cross portion; 72. Upper bending portion; 73. Transfer arc portion; 8. Metal screw. DETAILED DESCRIPTION

[0016] In order to make the technical solution and advantages of the utility model clearer, the utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application. Example

[0017] like Figure 1 As shown, a filter includes a cavity 1. The cavity 1 is in a rectangular shape, and is used to accommodate a plurality of linearly arranged resonators 5. Each resonator 5 is matched and connected with a frequency tuning screw 3. Therefore, the frequency tuning screw 3 and the resonator 5 that cooperate with each other can achieve an effective filtering effect in the cavity 1.

[0018] like Figure 1 , Figure 2 As shown, a capacitive coupling connecting piece 7 and three linearly arranged resonators 5 are arranged in the cavity 1. A tuning cavity 11 is arranged in the cavity 1 to accommodate the resonators 5. The tuning cavities 11 in the resonator 5 parts at both ends are used to connect with the two ends of the capacitive coupling connecting piece 7, and the resonator 5 at one end is connected with a capacitive coupling column 13, and the tuning cavity 11 matching the resonator 5 at the other end is provided with a capacitive coupling side column 12 connected to the inner side wall of the cavity 1. Both ends of the capacitive coupling connecting piece 7 are plugged with metal screws 8 threadedly connected to the corresponding capacitive coupling column 13 and the capacitive coupling side column 12. Therefore, the metal screws 8 are effectively fastened and connected with the capacitive coupling column 13 and the capacitive coupling side column 12, so as to prevent the two ends of the capacitive coupling connecting piece 7 from being separated from the corresponding capacitive coupling column 13 and the capacitive coupling side column 12.

[0019] At the same time, three fixing columns 15 are provided in the tuning cavity 11, which are matched and connected with the corresponding resonators 5, and the resonator 5 is provided with fixing screws 6 which are inserted from top to bottom into the corresponding fixing columns 15 and connected with the inner threads. The fixing screws 6 match the fixing columns 15 and realize the stable connection of the resonator 5, so that the resonator 5 and the frequency tuning screw 3 remain relatively still, so as to effectively avoid the problem of reduced filtering effect caused by relative movement.

[0020] like Figure 2 As shown, the capacitive coupling column 13 is connected to the capacitive coupling adjustment position 14, and the capacitive coupling adjustment position 14 is integrally formed with the corresponding fixing column 15. At the same time, a cover plate 2 is provided at the top of the cavity 1. The cover plate 2 is plugged with three frequency tuning screws 3 that match the corresponding resonators 5 and are inserted into the upper end openings of the corresponding resonators 5. And a coupling tuning screw 4 is plugged between two adjacent frequency tuning screws 3. The frequency tuning screw 3 and the coupling tuning screw 4 are both threadedly connected with nuts that abut against the outer plate of the cover plate 2, so as to achieve the effect of improving the stability of the fixed connection between the frequency tuning screw 3 and the coupling tuning screw 4 and the cover plate 2.

[0021] It should be noted that the capacitive coupling connecting piece 7 in the embodiment of the present application includes a connecting cross portion 71 and an upper bending portion 72 connected to the connecting cross portion 71. The connecting cross portion 71 is used to connect to the capacitive coupling column 13, and the upper bending portion 72 is used to connect to the capacitive coupling side column 12. The upper bending portion 72 extends upward from the corresponding end of the connecting cross portion 71, and then extends to the other end of the connecting cross portion 71 and then extends backward to cooperate and fix with the capacitive coupling side column 12. Of course, in view of the position adjustment of the capacitive coupling side column 12 in the corresponding inner cavity, the specific structure of the upper bending portion 72 is suitable for making appropriate adjustments. At the same time, according to the difference in height between the capacitive coupling column 13 and the capacitive coupling side column 12, the upper bending portion 72 can be a downward bending structure. Example

[0022] The difference between the second embodiment and the first embodiment is that in the second embodiment, in order to further improve the adaptability of the capacitive coupling connecting piece 7, a transfer arc portion 73 is provided at the position where the connecting transverse portion 71 is located to match the resonator 5 located in the middle.

[0023] In summary, the present application provides a filter, which optimizes the connection structure of the capacitive coupling connecting piece 7 and uses metal screws 8 instead of plastic screws to connect and fix the capacitive coupling connecting piece 7 and the cavity 1, so as to reduce the difficulty of achieving a capacitive coupling zero point, thereby reducing costs and assembly difficulty; at the same time, in the development direction of multiplexed filters, the purpose of reducing the overall dimensions of the filter and avoiding occasional zero points that are difficult to achieve due to a straight row of cavities is achieved.

[0024] The "first", "second", "third", "fourth", etc. (if any) referred to in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods or devices.

[0025] It should be noted that the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0026] Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A filter, comprising a cavity (1), wherein a capacitive coupling connecting piece (7) and three linearly arranged resonators (5) are arranged in the cavity (1), characterized in that: The cavity (1) is provided with a tuning cavity (11), and the tuning cavity (11) located in the resonator (5) at both ends is used to connect with the two ends of the capacitive coupling connecting piece (7), and the resonator (5) at one end is connected with a capacitive coupling column (13), and the tuning cavity (11) matched with the resonator (5) at the other end is provided with a capacitive coupling side column (12) connected with the inner side wall of the cavity (1), and both ends of the capacitive coupling connecting piece (7) are plugged with metal screws (8) threadedly connected with the corresponding capacitive coupling column (13) and the capacitive coupling side column (12).

2. A filter according to claim 1, characterized in that: The tuning cavity (11) is provided with three fixing columns (15) respectively matched and connected with the corresponding resonators (5), and the resonator (5) is provided with fixing screws (6) inserted from top to bottom into the internal threads of the corresponding fixing columns (15).

3. A filter according to claim 2, characterized in that: The capacitive coupling column (13) is connected to a capacitive coupling adjustment position (14), and the capacitive coupling adjustment position (14) is integrally formed with the corresponding fixing column (15).

4. A filter according to claim 1, characterized in that: A cover plate (2) is provided at the top of the cavity (1), and the cover plate (2) is plugged with three frequency tuning screws (3) which are matched with the corresponding resonators (5) and inserted into the upper openings of the corresponding resonators (5).

5. A filter according to claim 4, characterized in that: A coupling tuning screw (4) is inserted between two adjacent frequency tuning screws (3), and both the frequency tuning screw (3) and the coupling tuning screw (4) are threadedly connected with a nut that abuts against the outer plate of the cover plate (2).

6. A filter according to claim 1, characterized in that: The capacitive coupling connecting piece (7) comprises a connecting transverse portion (71) and an upper bending portion (72) connected to the connecting transverse portion (71), wherein the connecting transverse portion (71) is used to connect to the capacitive coupling upright column (13), the upper bending portion (72) is used to connect to the capacitive coupling side column (12), and the connecting transverse portion (71) is provided with a transfer arc portion (73).

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