Dielectric filter with built-in ground type negative coupling structure and manufacturing method thereof

Abstract

The dielectric filter with a built-in grounded negative coupling structure provided by this invention includes: a dielectric block, resonant holes formed on the dielectric block, and a conductive layer laid on the surface of the dielectric block and the inner wall of the resonant holes. There are at least two resonant holes, dividing the dielectric filter into two adjacent resonators. The dielectric filter also includes a negative coupling structure disposed between these two resonators. By including a conductive sheet embedded in the dielectric block and a metallized blind hole connecting and conducting the conductive sheet and the conductive layer, and by spaced the conductive sheet and the metallized blind hole from the resonant holes, grounding can be introduced into the interior of the dielectric block while preserving the strength of the dielectric block as much as possible, avoiding defects such as deformation and local collapse during firing, thereby accurately controlling the zero point position. The manufacturing method provided by this invention achieves negative coupling by prefabricating conductive sheets and metallized blind holes in the dielectric block. The steps are simple, easy to implement, and have a high yield rate.

Description

Technical Field

[0001] This invention relates to the field of dielectric filter technology, specifically to a dielectric filter with a built-in grounded negative coupling structure and its manufacturing method. Background Technology

[0002] A dielectric filter is a microwave filter that achieves frequency selection by using a dielectric resonant cavity and multi-stage coupling. The structure of a traditional dielectric filter generally includes a dielectric block and a grounding conductive layer laid on the surface of the dielectric block. In order to achieve negative coupling, the ground needs to be introduced into the interior of the dielectric block through a through coupling slot. This type of slot reduces the strength of the dielectric block itself, and is prone to deformation, local collapse and other defects during firing. It is difficult to accurately control the zero point position, and it is also difficult to achieve a lateral ground plane inside the dielectric block, thus limiting the negative coupling effect. Summary of the Invention

[0003] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a dielectric filter with a built-in grounded negative coupling structure and its manufacturing method.

[0004] To achieve the above objectives, the product in the technical solution adopted by the present invention is a dielectric filter with a built-in grounded negative coupling structure, comprising: a dielectric block, a resonant hole opened on the dielectric block, and a conductive layer laid on the surface of the dielectric block and the inner wall of the resonant hole. There are at least two resonant holes, which divide the dielectric filter into two adjacent resonators. The dielectric filter also includes a negative coupling structure disposed between the two resonators. The negative coupling structure includes a conductive sheet embedded in the dielectric block and a metallized blind hole connecting and conducting the conductive sheet and the conductive layer. The conductive sheet and the metallized blind hole are spaced apart from the resonant holes.

[0005] Preferably, the metallized blind via is connected to both ends of the conductive sheet and extends in the opposite direction.

[0006] More preferably, the metallized blind via is perpendicularly connected to the conductive sheet.

[0007] Preferably, the centerline of the metallized blind hole is parallel to the centerline of the resonant hole.

[0008] Preferably, the plane containing the conductive sheet is perpendicular to the axis of the resonant hole.

[0009] Preferably, there are multiple conductive sheets arranged in parallel and staggered manner, and adjacent conductive sheets are connected and conductive through metallized connecting vias.

[0010] Preferably, the dielectric block is formed by stacking and sintering multiple ceramic sheets, the conductive sheet is formed by curing a metal paste coated on the surface of one of the ceramic sheets, and the metallized blind hole is formed by combining through holes opened on the ceramic sheets on both sides of the conductive sheet, with the inner wall of the through hole provided with cured metal paste.

[0011] Preferably, there are four resonant holes, which divide the dielectric filter into four resonators. A cross-shaped isolation groove is provided between the four resonators, and the conductive layer is also applied to the inner wall of the isolation groove.

[0012] To achieve the above objectives, the method employed in this invention is a method for manufacturing the aforementioned dielectric filter, comprising the following steps: S1. Decompose the dielectric block into several parallel ceramic sheets; S2. Through holes corresponding to the positions of the metallized blind holes are made on the ceramic sheet where the conductive sheet is located and on the ceramic sheets on both sides. S3. Print metal paste on the corresponding positions of the conductive sheets and the inner walls of the through holes on the ceramic sheet; S4. Sinter all ceramic sheets together to obtain a dielectric block; S5. Metallize the dielectric block to form a conductive layer to obtain a dielectric filter.

[0013] Preferably, the conductive sheet in step S2 is a plurality of sheets arranged in parallel and staggered manner. Step S2 also includes the step of opening connecting vias on the ceramic sheet where the conductive sheet is located and on the ceramic sheets between adjacent conductive sheets. In step S3, the metal paste is also printed on the inner wall of the connecting via.

[0014] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art: The dielectric filter with a built-in grounded negative coupling structure provided by this invention includes: a dielectric block, resonant holes formed on the dielectric block, and a conductive layer laid on the surface of the dielectric block and the inner wall of the resonant holes. There are at least two resonant holes, dividing the dielectric filter into two adjacent resonators. The dielectric filter also includes a negative coupling structure disposed between these two resonators. By including a conductive sheet embedded in the dielectric block and a metallized blind hole connecting and conducting the conductive sheet and the conductive layer, and by spaced the conductive sheet and the metallized blind hole from the resonant holes, grounding can be introduced into the interior of the dielectric block while preserving the strength of the dielectric block as much as possible, avoiding defects such as deformation and local collapse during firing, thereby accurately controlling the zero point position. The manufacturing method provided by this invention achieves negative coupling by prefabricating conductive sheets and metallized blind holes in the dielectric block. The steps are simple, easy to implement, and have a high yield rate. Attached Figure Description

[0015] Figure 1This is a three-dimensional schematic diagram of Embodiment 1 of the present invention.

[0016] Figure 2 This is a three-dimensional schematic diagram of Embodiment 2 of the present invention.

[0017] Figure 3 This is a three-dimensional schematic diagram of Embodiment 3 of the present invention.

[0018] Figure 4 yes Figure 3 A three-dimensional diagram before layering.

[0019] Figure 5 yes Figure 4 A schematic diagram of the structure of a ceramic sheet with conductive plates in it.

[0020] Figure 6 yes Figure 5 A three-dimensional schematic diagram.

[0021] Figure 7 yes Figure 3 A three-dimensional diagram after layering.

[0022] Figure 8 yes Figure 3 Electrical performance diagram.

[0023] Wherein: 10. Dielectric block; 11. Resonator; 12. Isolation groove; 13. Ceramic sheet; 14. Through hole; 20. Resonant hole; 30. Negative coupling structure; 31. Conductive sheet; 32. Metallized blind hole; 33. Connection via. Detailed Implementation

[0024] Example 1, as Figure 1 As shown, the dielectric filter with a built-in grounded negative coupling structure provided by the present invention includes: a dielectric block 10, a resonant hole 20 formed on the dielectric block 10, and a conductive layer (not shown in the figure) laid on the surface of the dielectric block 10 and the inner wall of the resonant hole 20. There are two resonant holes 20, which divide the dielectric filter into two adjacent resonators 11. The dielectric filter also includes a negative coupling structure 30 disposed between the two resonators 11. The negative coupling structure 30 includes a conductive sheet 31 embedded in the dielectric block 10, and a metallized blind hole 32 connecting and conducting the conductive sheet 31 and the conductive layer. The conductive sheet 31 and the metallized blind hole 32 are spaced apart from the resonant hole 20.

[0025] The advantage of this setup is that it allows grounding to be introduced into the dielectric block while preserving the strength of the dielectric block itself as much as possible, avoiding defects such as deformation and local collapse during firing, thereby accurately controlling the zero-point position.

[0026] In this embodiment, the metallized blind vias 32 are vertically connected to both ends of the conductive sheet 31 and extend in the opposite direction. The openings of the metallized blind vias 32 are located on the surface of the dielectric block 10. That is, the two metallized blind vias 32 penetrate the surfaces of a pair of opposing sides of the dielectric block 10. Furthermore, the axis of the metallized blind vias 32 is parallel to the axis of the resonant hole 11, and the plane where the conductive sheet 31 is located is perpendicular to the axis of the resonant hole 11.

[0027] Example 2, as Figure 2 As shown, Embodiment 2 is basically the same as Embodiment 1, except that in Embodiment 2, there are two conductive sheets 31, which are arranged in parallel and staggered, and adjacent conductive sheets 31 are connected and conductive through metallized connection vias 33.

[0028] Example 3, as Figures 3 to 8 As shown, Embodiment 3 is basically the same as Embodiment 1, except that in Embodiment 3, there are four resonant holes 20, which divides the dielectric filter into four resonators 11. A cross-shaped isolation groove 12 is provided between these four resonators 11, and a conductive layer is also laid on the inner wall of the isolation groove 12. Input and output interfaces 21 are provided on the back of two resonant holes 20, and the resonators 11 corresponding to these two resonant holes 20 are not provided with negative coupling structures 30.

[0029] In Example 3, the dielectric block 10 is formed by stacking and sintering eight ceramic sheets 13. The conductive sheet 31 is formed by curing a metal paste coated on the surface of the fifth ceramic sheet 13. The metallized blind hole 32 is formed by combining through holes 14 opened on the ceramic sheets 13 on both sides of the conductive sheet 31. The inner wall of the through hole 14 is provided with cured metal paste. The dielectric block 10 in Example 1 and Example 2 has the same structure as the dielectric block 10 in Example 3.

[0030] The present invention also provides a method for manufacturing the above-mentioned dielectric filter, comprising the following steps: S1. Decompose the dielectric block 10 into several parallel ceramic sheets 13; S2. Through holes 14 corresponding to the positions of metallized blind holes 32 are made on the ceramic sheet 13 where the conductive sheet 31 is located and on the ceramic sheets 13 on both sides. S3. Print metal paste on the position corresponding to the conductive sheet 31 on the ceramic sheet 13 and on the inner wall of the through hole 14; S4. Sinter all ceramic sheets 13 in layers to obtain dielectric block 10; S5. Metallize dielectric block 10 to form a conductive layer to obtain a dielectric filter.

[0031] This manufacturing method achieves built-in grounding negative coupling by prefabricating conductive sheets and metallized blind holes within the dielectric block. The steps are simple, easy to implement, and have a high yield rate.

[0032] Preferably, there are two conductive sheets 31 in step S2, which are arranged in parallel and staggered. Step S2 also includes the step of opening connecting vias 33 on the ceramic sheet 13 where the conductive sheet 31 is located and on the ceramic sheet 13 between adjacent conductive sheets 31. In step S3, the metal paste is also printed on the inner wall of the connecting vias 33.

[0033] Furthermore, in step S1, by controlling the thickness of the ceramic sheet 13, connection vias 33 are opened on all ceramic sheets 13 with conductive sheets 31 to ensure the connection effect.

[0034] The embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for manufacturing a dielectric filter, the dielectric filter comprising a dielectric block, resonant holes formed on the dielectric block, and conductive layers disposed on the surface of the dielectric block and the inner wall of the resonant holes, wherein there are at least two resonant holes, and the dielectric filter is divided into two adjacent resonators, characterized in that: The dielectric filter also includes a negative coupling structure between the two resonators. The negative coupling structure includes a conductive sheet embedded in the dielectric block and a metallized blind hole that connects and conducts between the conductive sheet and the conductive layer. The metallized blind hole is connected to both ends of the conductive sheet and extends in the opposite direction. The conductive sheet and the metallized blind hole are spaced apart from the resonant hole. The method for manufacturing this dielectric filter includes the following steps: S1. Decompose the dielectric block into several parallel ceramic sheets; S2. Through holes corresponding to the positions of the metallized blind holes are made on the ceramic sheet where the conductive sheet is located and on the ceramic sheets on both sides. S3. Print metal paste on the corresponding positions of the conductive sheets and the inner walls of the through holes on the ceramic sheet; S4. Sinter all ceramic sheets together to obtain a dielectric block; S5. Metallize the dielectric block to form a conductive layer to obtain the dielectric filter.

2. The manufacturing method according to claim 1, characterized in that: In step S2, there are multiple conductive sheets arranged in parallel and staggered. Step S2 also includes the step of opening connecting vias on the ceramic sheet where the conductive sheet is located and on the ceramic sheets between adjacent conductive sheets. In step S3, the metal paste is also printed on the inner wall of the connecting vias.

3. The manufacturing method according to claim 1, characterized in that: The metallized blind via is perpendicularly connected to the conductive sheet.

4. The manufacturing method according to claim 1, characterized in that: The centerline of the metallized blind hole is parallel to the centerline of the resonant hole.

5. The manufacturing method according to claim 1, characterized in that: The plane containing the conductive sheet is perpendicular to the axis of the resonant hole.

6. The manufacturing method according to claim 1, characterized in that: The conductive sheets are multiple and arranged in parallel and staggered manner, and adjacent conductive sheets are connected and conductive through metallized connecting vias.

7. The manufacturing method according to claim 1, characterized in that: The dielectric block is formed by stacking and sintering multiple ceramic sheets. The conductive sheet is formed by curing a metal paste coated on the surface of one of the ceramic sheets. The metallized blind hole is formed by combining through holes opened on the ceramic sheets on both sides of the conductive sheet. The inner wall of the through hole is provided with cured metal paste.

8. The manufacturing method according to claim 1, characterized in that: The resonant aperture has four holes, which divide the dielectric filter into four resonators. A cross-shaped isolation groove is provided between the four resonators, and the conductive layer is also applied to the inner wall of the isolation groove.

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