Preparation method of dielectric filter and dielectric filter

Abstract

The invention relates to a preparation method of a dielectric filter and the dielectric filter. The preparation method comprises the steps that a filter body is prepared, the filter body is provided with at least three resonant cavities, and the two non-adjacent resonant cavities are the first resonant cavity and the second resonant cavity; a first coupling hole and a second coupling hole are machined in the side wall of the filter body, the first coupling hole corresponds to the first resonant cavity, and the second coupling hole corresponds to the second resonant cavity; performing metal plating treatment on the filter body, and forming a metal plating layer on the surface of the filter body; and the metal coating is etched to form a first metal coating and a second metal coating which are isolated from each other, and the second metal coating covers the first coupling hole and the second coupling hole and extends from the first coupling hole to the second coupling hole. The second metal coating is arranged between the first coupling hole and the second coupling hole, so that the assembly difficulty is reduced, and the consistency of batch production is improved.

Description

Technical Field

[0001] The present application relates to the field of filtering equipment, and in particular to a method for preparing a dielectric filter and a dielectric filter. Background Art

[0002] Filters are divided into metal cavity filters and dielectric filters. In order to meet the requirements of satellite miniaturization, the filter needs to be miniaturized. The miniaturization design of metal cavity filters may bring the risk of vacuum micro-discharge. Dielectric filters are easier to achieve miniaturization and lightweight. However, the coupling structure of existing dielectric filters all realizes the electrical connection of different resonant units by connecting the PCB microstrip board with metal rods. When preparing dielectric filters, the welding accuracy of the metal rods connecting the PCB microstrip board is poor, which may affect the performance of the dielectric filter. Summary of the invention

[0003] Based on the above problems, the present application provides a method for preparing a dielectric filter and a dielectric filter, so as to improve the preparation accuracy of the dielectric filter.

[0004] An embodiment of the present application provides a method for preparing a dielectric filter, comprising:

[0005] Prepare a filter body, wherein the filter body is provided with at least three resonant cavities, wherein two non-adjacent resonant cavities are a first resonant cavity and a second resonant cavity;

[0006] A first coupling hole and a second coupling hole are processed on the side wall of the filter body, wherein the first coupling hole corresponds to the first resonant cavity, and the second coupling hole corresponds to the second resonant cavity;

[0007] Performing metal plating on the filter body to form a metal plating layer on the surface of the filter body;

[0008] The metal plating layer is etched to form a first metal plating layer and a second metal plating layer isolated from each other, wherein the second metal plating layer covers the first coupling hole and the second coupling hole and extends from the first coupling hole to the second coupling hole.

[0009] According to some embodiments of the present application, processing the first coupling hole and the second coupling hole on the side wall of the filter body includes:

[0010] Processing a coupling groove on the side wall of the filter body;

[0011] The first coupling hole and the second coupling hole are processed at the bottom of the coupling groove.

[0012] According to some embodiments of the present application, etching the metal plating layer includes: etching the metal plating layer at the bottom of the coupling groove.

[0013] According to some embodiments of the present application, the method for preparing the dielectric filter further includes: welding a cover plate to the first metal coating so that the cover plate closes the coupling slot.

[0014] According to some embodiments of the present application, both the first coupling hole and the second coupling hole are through holes.

[0015] According to some embodiments of the present application, both the first coupling hole and the second coupling hole are blind holes.

[0016] According to some embodiments of the present application, the apertures of the first coupling hole and the second coupling hole are both 1 to 4 mm.

[0017] According to some embodiments of the present application, the method for preparing the dielectric filter further includes: welding an electrical connector to the filter body.

[0018] According to some embodiments of the present application, the method for preparing the dielectric filter further includes: machining filter grooves on two opposite side walls at the top of the filter body.

[0019] According to some embodiments of the present application, the ratio of the length of the filter slot to the length of the filter body is 1:1.2-2, and the ratio of the height of the filter slot to the height of the filter body is 1:1.5-3.

[0020] An embodiment of the present application provides a dielectric filter, which is prepared by the method described above.

[0021] The preparation method of the dielectric filter of the present application sets a second metal coating between the first coupling hole and the second coupling hole, avoids the assembly of the metal rod and the PCB board, and reduces the difficulty of assembly. The metal coating is separated into the first metal coating and the second metal coating by etching, and the preparation accuracy is high, which is conducive to improving the consistency of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without exceeding the scope of protection required by the present application.

[0023] Figure 1 is a flow chart of a method for preparing a dielectric filter according to an embodiment of the present application;

[0024] Figure 2 It is a schematic diagram of the internal structure of the filter body of the embodiment of the present application;

[0025] Figure 3 is a schematic diagram of a filter body according to an embodiment of the present application;

[0026] Figure 4 is a schematic diagram of a metal coating according to an embodiment of the present application;

[0027] Figure 5 is a schematic diagram of a dielectric filter according to an embodiment of the present application;

[0028] Figure 6 is a schematic diagram of the second metal coating of an embodiment of the present application;

[0029] Figure 7 It is a schematic diagram of the cover plate and the electrical connector according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solution of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present application.

[0031] like Figure 1 As shown, an embodiment of the present application provides a method for preparing a dielectric filter, comprising:

[0032] S1. Prepare a filter body, wherein the filter body is provided with at least three resonant cavities, wherein two non-adjacent resonant cavities are a first resonant cavity and a second resonant cavity.

[0033] like Figure 2 As shown, the filter body 1 is a dielectric material, for example, a ceramic material. A ceramic body is prepared according to a preset size, and the filter body 1 is obtained after the ceramic body is sintered. The filter body 1 is sequentially provided with at least three resonant cavities 11, and the resonant cavities 11 extend upward from the bottom surface of the filter body 1. Among them, the two non-adjacent resonant cavities are the first resonant cavity 11a and the second resonant cavity 11b. Optionally, the filter body 1 is roughly a rectangular parallelepiped.

[0034] S2. Processing a first coupling hole and a second coupling hole on the side wall of the filter body, wherein the first coupling hole corresponds to the first resonant cavity, and the second coupling hole corresponds to the second resonant cavity.

[0035] like Figure 3As shown, a first coupling hole 21 and a second coupling hole 22 are machined on the same side wall of the filter body 1 by machining equipment, the first coupling hole 21 corresponds to the first resonant cavity 11a, and the first coupling hole 21 extends from the side wall of the filter body 1 to the first resonant cavity 11a. The second coupling hole 22 corresponds to the second resonant cavity 11b, and the second coupling hole 22 extends from the side wall of the filter body 1 to the second resonant cavity 11b.

[0036] S3, performing metal plating on the filter body to form a metal plating layer on the surface of the filter body.

[0037] like Figure 4 As shown, the filter body 1 is subjected to metal plating as a whole, for example, the metal plating is silver plating, and a metal plating layer 3 is formed on the entire surface of the filter body 1. Optionally, the thickness of the metal plating layer 3 is about 0.01 mm. The resonant cavity 11 is attached with the metal plating layer 3 to form a resonant unit.

[0038] S4. Etching the metal plating layer to form a first metal plating layer and a second metal plating layer that are isolated from each other, wherein the second metal plating layer covers the first coupling hole and the second coupling hole and extends from the first coupling hole to the second coupling hole.

[0039] like Figure 5 As shown, laser etching is performed on the metal coating 3 to etch an isolation region 4 around the first coupling hole 21 and the second coupling hole 22 to form a first metal coating 31 and a second metal coating 32 isolated from each other. The first metal coating 31 and the second metal coating 32 are insulated from each other.

[0040] The second metal plating layer 32 covers the first coupling hole 21 and the second coupling hole 22, and the second metal plating layer 33 has a uniform thickness. For example, when the first coupling hole 21 and the second coupling hole 22 are both through holes, the second metal plating layer 32 covers the hole wall of the first coupling hole 21 and the hole wall of the second coupling hole 22. The second metal plating layer 32 is a continuous metal plating layer, extending from the first coupling hole 21 to the second coupling hole 22 to achieve electrical connection between the first coupling hole 21 and the second coupling hole 22. The first coupling hole 21, the second coupling hole 22 and the second metal plating layer 32 form a coupling structure to achieve cross-coupling of non-adjacent resonant units. Optionally, the number of structures on the dielectric filter is set according to demand.

[0041] The first metal plating layer 31 covers the surface of the filter body 1 except the second metal plating layer 32 and the isolation region 4 .

[0042] The dielectric filter of this embodiment is filled with dielectric material. In the working mode, the generated charged particles are difficult to penetrate, and it is difficult to form secondary electron excitation, and the power threshold is high. The dielectric material has small deformation at high and low temperatures, the material is stable, and has good high and low temperature performance and consistency.

[0043] The dielectric filter does not use metal rods and PCB boards, and almost does not require assembly, which reduces assembly difficulty. The size of the second metal coating 32 and the isolation area 4 is easy to control, and the preparation accuracy is high, which is conducive to improving product consistency during mass production.

[0044] like Figure 3 As shown, in some embodiments, in step S2, processing the first coupling hole and the second coupling hole on the side wall of the filter body includes:

[0045] A coupling groove 23 is machined on the side wall of the filter body 1;

[0046] A first coupling hole 21 and a second coupling hole 22 are formed at the bottom of the coupling groove 23 .

[0047] Optionally, the depth of the coupling groove 23 is 1 to 3 mm, for example, the depth of the coupling groove 23 is 2 mm. The first coupling hole 21, the second coupling hole 22 and the second metal plating layer 32 are all located at the bottom of the coupling groove 23, so as to provide protection for the coupling structure. The depth of the coupling groove 23 affects the hole depth of the first coupling hole 21 and the second coupling hole 22. The greater the depth value of the coupling groove 23, the greater the coupling degree.

[0048] In some embodiments, in step S4 , etching the metal plating layer includes: etching the metal plating layer 3 at the bottom of the coupling groove 23 , so that the isolation region 4 is located at the bottom of the coupling groove 23 .

[0049] like Figure 6 As shown, the second metal plating layer 32 includes: a first cylindrical portion 321, a second cylindrical portion 322, a first annular portion 323, a second annular portion 324 and a strip portion 325. The first cylindrical portion 321 and the second cylindrical portion 322 are both hollow structures. The first cylindrical portion 321 is attached to the hole wall of the first coupling hole 21, and the second cylindrical portion 322 is attached to the hole wall of the second coupling hole 22. The first annular portion 323 and the second annular portion 324 are both attached to the bottom of the coupling groove 23. The first annular portion 323 is coaxially arranged and connected to the first cylindrical portion 321, and the second annular portion 324 is coaxially arranged and connected to the second cylindrical portion 322. The strip portion 325 is attached to the bottom of the coupling groove 23, and the strip portion 325 extends from the first annular portion 323 to the second annular portion 324. The shapes of the isolation region 4 and the coupling groove 23 are both adapted to the second metal plating layer 32.

[0050] Optionally, the width D1 of the strip portion 325 is 0.3-2 mm. For example, the width D1 of the strip portion 325 is 1 mm. The larger the width D1 of the strip portion 325 is, the greater the coupling degree is.

[0051] like Figure 7As shown, in some embodiments, the method further includes welding the cover plate 5 to the first metal coating 31 , so that the cover plate 5 closes the coupling slot 23 .

[0052] The cover plate 5 is made of metal, and the cover plate 5 closes the notch of the coupling slot 23. For example, the cover plate 5 is a rectangular parallelepiped, and the size of the cover plate 5 is set to be slightly larger than the notch size of the coupling slot 23. The cover plate 5 is welded to the first metal plating layer 31 on the side wall of the filter body 1 so that the cover plate 5 closes the notch of the coupling slot 23. The cover plate 5 can protect the coupling structure, prevent electromagnetic leakage, and avoid generating other interference signals.

[0053] In some embodiments, both the first coupling hole 21 and the second coupling hole 22 are through holes. The first cylindrical portion 321 of the second metal plating layer 32 extends to connect with the first metal plating layer on the inner wall of the first resonant cavity 11a, and the second cylindrical portion 322 extends to connect with the first metal plating layer on the inner wall of the second resonant cavity 11b, so that two non-adjacent resonant units achieve inductive cross coupling.

[0054] In some embodiments, the first coupling hole 21 and the second coupling hole 22 are both blind holes. The second metal plating layer 32 covers the bottom of the first coupling hole 21 and the bottom of the second coupling hole 22, and two non-adjacent resonant units achieve capacitive cross coupling.

[0055] In some embodiments, the apertures of the first coupling hole 21 and the second coupling hole 22 are both 1-4 mm, for example, the apertures of the first coupling hole 21 and the second coupling hole 22 are both 1.5 mm. The apertures of the first coupling hole 21 and the second coupling hole 22 are the same. If the apertures of the first coupling hole 21 and the second coupling hole 22 are too large, the processing amount will increase, and if the apertures of the first coupling hole 31 and the second coupling hole 32 are too small, they are difficult to process.

[0056] In some embodiments, the method further comprises: welding the electrical connector 6 to the filter body 1. The electrical connector 6 may be an existing electrical connector. The electrical connector 6 is disposed at the end of the filter body 1. For example, two electrical connectors 6 are disposed at the two ends of the filter body 1, respectively.

[0057] In some embodiments, the method further comprises: processing filter grooves 7 on two opposite side walls at the top of the filter body. The filter grooves 7 can adjust the frequency of the second harmonic generated by the filter to a region with a large difference from the working passband of the filter.

[0058] For example, the working passband of the filter is 1 GHz-1.2 GHz, and the frequency of the second harmonic generated by the filter is 2.0-2.1 GHz when the filter slot 7 is not provided. After the filter slot 7 is provided, the frequency of the second harmonic generated by the filter is 2.6-2.8 GHz.

[0059] In some embodiments, the ratio of the length L1 of the filter slot 7 to the length L2 of the filter body 1 is 1:1.2-2, and the ratio of the height H1 of the filter slot 7 to the height H2 of the filter body 1 is 1:1.5-3. For example, the length L1 of the filter slot 7 is 50 mm, and the length L2 of the filter body 1 is 75 mm. The height H1 of the filter slot 7 is 6 mm, and the height H2 of the filter body 1 is 12 mm. The depth of the filter slot 7 is set according to demand, for example, the depth of the filter slot 7 is 2 mm. .

[0060] The dielectric filter prepared in this embodiment is easy to miniaturize to meet the requirements of satellite miniaturization. The dielectric filter has fewer parts, high consistency in batch production, and improved production yield.

[0061] An embodiment of the present application also provides a dielectric filter, which is prepared using the method described above.

[0062] Example 1

[0063] 1. A ceramic body is prepared according to a preset size, and a filter body is obtained after sintering the ceramic body. The filter body is sequentially provided with 9 resonant cavities, wherein two non-adjacent resonant cavities are a first resonant cavity and a second resonant cavity.

[0064] 2. A coupling groove is machined on the side wall of the filter body, and a first coupling hole and a second coupling hole are machined on the bottom of the coupling groove. The first coupling hole and the second coupling hole are both through holes with an aperture of 1.5 mm. The first coupling hole corresponds to the first resonant cavity, and the second coupling hole corresponds to the second resonant cavity.

[0065] 3. Process filter grooves on two opposite side walls at the top of the filter body.

[0066] 4. The filter body is silver-plated as a whole, and the thickness of the silver layer is 0.01mm.

[0067] 5. Etching the silver layer to form a first metal plating layer and a second metal plating layer isolated from each other, wherein the second metal plating layer covers the first coupling hole and the second coupling hole and extends from the first coupling hole to the second coupling hole.

[0068] 6. Weld the cover plate to the first metal coating, and the cover plate closes the coupling groove.

[0069] 7. Weld the electrical connector to the filter body.

[0070] The first metal coating and the second metal coating of this embodiment are formed by one-time electroplating, which simplifies the preparation process of the dielectric filter. The etching process has high precision, which is beneficial to improving the dimensional accuracy of the second metal coating and the isolation area and reducing the workload of later debugging the coupling degree.

[0071] The embodiments of the present application are described in detail above. 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 technical solution and core ideas of the present application. Therefore, changes or deformations made by those skilled in the art based on the ideas of the present application, the specific implementation methods and the scope of application of the present application, all belong to the scope of protection of the present application. In summary, the contents of this specification should not be construed as limiting the present application.

Claims

1. A method for preparing a dielectric filter, characterized in that: include: Prepare a filter body, wherein the filter body is provided with at least three resonant cavities, wherein two non-adjacent resonant cavities are a first resonant cavity and a second resonant cavity; A first coupling hole and a second coupling hole are processed on the side wall of the filter body, wherein the first coupling hole corresponds to the first resonant cavity, and the second coupling hole corresponds to the second resonant cavity; Performing metal plating on the filter body to form a metal plating layer on the surface of the filter body; The metal plating layer is etched to form a first metal plating layer and a second metal plating layer isolated from each other, wherein the second metal plating layer covers the first coupling hole and the second coupling hole and extends from the first coupling hole to the second coupling hole.

2. The method for preparing a dielectric filter according to claim 1, characterized in that: The processing of the first coupling hole and the second coupling hole on the side wall of the filter body comprises: Processing a coupling groove on the side wall of the filter body; The first coupling hole and the second coupling hole are processed at the bottom of the coupling groove.

3. The method for preparing a dielectric filter according to claim 2, characterized in that: Etching the metal coating comprises: The metal plating layer is etched at the bottom of the coupling groove.

4. The method for preparing a dielectric filter according to claim 2, characterized in that: Also includes: The cover plate is welded to the first metal coating so that the cover plate closes the coupling groove.

5. The method for preparing a dielectric filter according to claim 1, characterized in that: The first coupling hole and the second coupling hole are both through holes or both blind holes.

6. The method for preparing a dielectric filter according to claim 1, characterized in that: The diameters of the first coupling hole and the second coupling hole are both 1-4 mm.

7. The method for preparing a dielectric filter according to claim 1, characterized in that: Also includes: The electric connector is welded to the filter body.

8. The method for preparing a dielectric filter according to claim 1, characterized in that: Also includes: Filter grooves are processed on two opposite side walls at the top of the filter body.

9. The method for preparing a dielectric filter according to claim 8, characterized in that: The ratio of the length of the filter groove to the length of the filter body is 1:1.2-2, and the ratio of the height of the filter groove to the height of the filter body is 1:1.5-3.

10. A dielectric filter, characterized in that: Prepared by the method according to any one of claims 1 to 9.

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