CN113823887A - Dielectric filter and manufacturing method thereof - Google Patents
Dielectric filter and manufacturing method thereof Download PDFInfo
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- CN113823887A CN113823887A CN202111148702.0A CN202111148702A CN113823887A CN 113823887 A CN113823887 A CN 113823887A CN 202111148702 A CN202111148702 A CN 202111148702A CN 113823887 A CN113823887 A CN 113823887A
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- straight hole
- hole
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P1/00—Auxiliary devices
- H01P1/20—Frequency-selective devices, e.g. filters
- H01P1/2002—Dielectric waveguide filters
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P11/00—Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type
- H01P11/007—Manufacturing frequency-selective devices
Abstract
The invention provides a dielectric filter, which comprises a filter body, a resonant hole penetrating through the filter body along the front and back directions and a conductive layer covering the inner wall surface of the resonant hole and the surface of the filter body, wherein the conductive layers on the front and back surfaces of the filter body respectively form a circuit and a signal electrode; the manufacturing method of the dielectric filter provided by the invention is simple to operate, low in processing difficulty, high in yield, suitable for batch production, free of extra cost, high in frequency and good in performance parameter.
Description
Technical Field
The present application relates to the field of communications technologies, and in particular, to a dielectric filter and a method for manufacturing the dielectric filter.
Background
The Dielectric filter (English Dielectric filter) is designed and manufactured by utilizing the characteristics of low loss, high Dielectric constant, small frequency temperature coefficient and thermal expansion coefficient, high power bearing and the like of a Dielectric ceramic material, and is composed of a plurality of longitudinal multistage ladder circuits connected in series or in parallel of long resonators.
The general structure of the conventional dielectric filter has two realization modes, one structure is that N (N is more than or equal to 2) resonant cavities which penetrate from the upper part to the lower part are arranged on an independent ceramic, and the structure is commonly called a conjoined dielectric filter; the other structure is that a resonant cavity penetrating from the upper part to the lower part is arranged on the independent ceramic to form a single resonator, and N (N is more than or equal to 2) single resonators are spliced together in a certain coupling mode to realize the function of the filter.
The width dimension of such dielectric filters is inversely proportional to the dielectric constant and center frequency of the ceramic material, i.e.
The dielectric filter comprises a dielectric filter, a circuit, a signal electrode, a resonant hole, a shielding shell, a dielectric filter, a filter core, a filter cover, a filter core, a filter cover, a filter core, a filter cover, a filter core, a filter and a filter core, a filter core, a filter core, a filter core, a filter core, a.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, provides a dielectric filter with higher frequency and better performance parameters under the condition of the same size, and also provides a manufacturing method of the dielectric filter.
In order to achieve the above object, the invention adopts a technical scheme that a dielectric filter comprises: the filter comprises a filter body, a resonance hole and a conducting layer, wherein the filter body is a cuboid ceramic dielectric block, the resonance hole penetrates through the filter body along the front-back direction, the conducting layer covers the inner wall surface of the resonance hole and the surface of the filter body, a circuit is formed after the conducting layer part covering the front surface of the filter body is removed, the conducting layer covering the rear surface of the filter body forms a short-circuit surface, a signal electrode electrically connected with the circuit is formed after the conducting layer part covering the upper surface of the filter body is removed, the resonance hole comprises a first straight hole and a second straight hole which are communicated, the first straight hole is positioned in front of the second straight hole, the first straight hole penetrates through the front surface of the filter body forwards to form a front opening of the resonance hole, and the second straight hole penetrates through the rear surface of the filter body backwards to form a rear opening of the resonance hole, the aperture of the second straight hole is larger than that of the first straight hole, and the hole depth of the second straight hole is larger than that of the first straight hole.
Preferably, the axis of the first straight hole coincides with the axis of the second straight hole.
Preferably, the aperture of the first straight hole is greater than or equal to 0.5mm, and the aperture of the second straight hole is greater than or equal to 2 times the aperture of the first straight hole.
Preferably, the second straight hole has a hole depth equal to or less than two thirds of the width of the filter body in the front-rear direction.
Preferably, there are a plurality of the resonance holes, the plurality of the resonance holes are arranged in parallel and at intervals along the left-right direction, and the axial lines of all the resonance holes are located on the same plane.
Preferably, the axes of the resonance holes are equidistant from the upper surface and the lower surface of the filter body.
In order to achieve the above object, the method in the technical scheme adopted by the invention is a manufacturing method of a dielectric filter, comprising the following steps:
a, pressing ceramic powder into a cuboid ceramic block, wherein a resonance hole penetrating through the ceramic block along the front-back direction is reserved in the ceramic block during pressing;
sintering the ceramic block into a filter body;
c, metalizing the filter body, and covering the inner wall surface of the resonance hole and the surface of the filter body with a conductive layer;
d, grinding part of the conductive layer on the front surface of the filter body to form a circuit on the front surface of the filter body, and grinding part of the conductive layer on the upper surface of the filter body to form a signal electrode electrically connected with the circuit on the upper surface of the filter body;
e, mounting a shielding shell to obtain the dielectric filter;
in step a the resonance hole comprises a first straight hole and a second straight hole which are communicated with each other, the first straight hole is located in front of the second straight hole, the axial lead of the first straight hole coincides with the axial lead of the second straight hole, the axial lead of the first straight hole equals to the distance between the upper surface and the lower surface of the filter body, the aperture of the second straight hole is larger than the aperture of the first straight hole, the hole depth of the second straight hole is larger than the hole depth of the first straight hole and is smaller than or equal to two thirds of the width of the filter body in the front-back direction, and the frequency of the dielectric filter is positively correlated with the hole depth of the second straight hole.
Preferably, the aperture of the first straight hole is greater than or equal to 0.5mm, the aperture of the second straight hole is greater than or equal to 2 times the aperture of the first straight hole, and the dielectric filter is also positively correlated with the aperture of the second straight hole.
Further preferably, the dielectric constant of the ceramic powder is greater than 9.
Further preferably, the frequency of the dielectric filter is 7500MHz or more.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
the invention provides a dielectric filter, which comprises a filter body, a resonance hole and a conductive layer, wherein the filter body is a cuboid ceramic dielectric block, the resonance hole penetrates through the filter body along the front-back direction, the conductive layer covers the inner wall surface of the resonance hole and the surface of the filter body, the conductive layer covering the front surface of the filter body forms a circuit, the conductive layer covering the rear surface of the filter body forms a short-circuit surface, the conductive layer covering the upper surface of the filter body forms a signal electrode electrically connected with the circuit, the first straight hole is positioned in front of the second straight hole by enabling the resonance hole to comprise a first straight hole and a second straight hole which are communicated, the aperture of the second straight hole is larger than that of the first straight hole, the depth of the second straight hole is larger than that of the first straight hole, the width size of the dielectric filter does not need to be reduced, the processing of the circuit, the signal electrode and the resonance hole and the installation of a shielding shell are convenient, the inductance value of the equivalent circuit of the dielectric filter is changed, so that the frequency of the dielectric filter is improved, the frequency of the dielectric filter is higher under the condition of the same size, and the processing difficulty is reduced due to the fact that the aperture of the second straight hole is enlarged, and the performance parameters of the dielectric filter are better; the manufacturing method of the dielectric filter provided by the invention is simple to operate, low in processing difficulty, high in yield, suitable for batch production, free of extra cost, high in frequency and good in performance parameter.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic front view of a dielectric filter according to a preferred embodiment of the present invention, in which the circuit and the signal electrode are not formed and the shield case is not mounted.
Fig. 2 is a rear view of fig. 1.
Fig. 3 is a schematic sectional view in the direction of a-a in fig. 1.
Fig. 4 and 5 are schematic perspective views of the dielectric filter in fig. 1 after a circuit and a signal electrode are manufactured and a shielding case is mounted.
Fig. 6 is a graph showing the electrical performance of a prior art dielectric filter having the same dimensions as those of fig. 4.
Fig. 7 is a graph of the electrical performance of the dielectric filter of fig. 4.
Wherein: 10. a filter body; 20. a resonant aperture; 21. a first straight hole; 22. a second straight hole; 23. a front opening; 24. a rear opening; 30. a conductive layer; 31. a circuit; 32. a signal electrode; 33. a short circuit plane; 40. and a shield case.
Detailed Description
The technical solutions in the embodiments of the present invention will be described in detail below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the description of the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
The up-down and left-right directions described in the present invention are the up-down and left-right directions in fig. 1, the front-back direction described in the present invention is the up-down direction in fig. 3, and the length, width, and height in the present invention respectively refer to the length of the dielectric filter in the left-right direction, the width in the front-back direction, and the height in the up-down direction.
As shown in fig. 1 to 5, the present invention provides a dielectric filter including: the filter comprises a filter body 10, a resonant hole 20, a conductive layer 30 and a shielding shell 40, wherein the filter body 10 is a rectangular ceramic dielectric block with the length, width and height of 13.0 x 3.2 x 3.0mm, the dielectric constant of the ceramic dielectric block is 9.8, the resonant hole 20 penetrates through the filter body 10 along the front and back direction, the conductive layer 30 covers the inner wall surface of the resonant hole 20 and the surface of the filter body 10, a circuit 31 is formed after the conductive layer 30 covering the front surface of the filter body 10 is partially removed, a short-circuit surface 33 is formed without removing the conductive layer 30 covering the rear surface of the filter body 10, a signal electrode 32 electrically connected with the circuit 31 is formed after the conductive layer 30 covering the upper surface of the filter body 10 is partially removed, the resonant hole 20 comprises a first straight hole 21 and a second straight hole 22 which are communicated, the axial lead of the first straight hole 21 is coincident with the axial lead of the second straight hole 22, the first straight hole 21 is positioned in front of the second straight hole 22, the first straight hole 21 penetrates the front surface of the filter body 10 forward to form a front opening 23 of the resonance hole 20, the second straight hole 22 penetrates the rear surface of the filter body 10 backward to form a rear opening 24 of the resonance hole 20, the aperture of the second straight hole 22 is larger than 2 times of the aperture of the first straight hole 21, the hole depth of the second straight hole 22 is larger than the hole depth of the first straight hole 21, and is less than or equal to two-thirds of the width of the filter body 10 in the front-rear direction.
The advantage that sets up like this lies in, need not to reduce dielectric filter's width dimension, has both made things convenient for the processing in circuit, signal electrode, resonance hole and the installation of shielding shell, has changed dielectric filter equivalent circuit's inductance value again to dielectric filter's frequency has been promoted, and it is higher to make dielectric filter frequency under the same size condition, because the aperture grow in the straight hole of second, has still reduced the processing degree of difficulty, makes dielectric filter's performance parameter better.
For the convenience of processing, the aperture of the first straight hole 21 is not small, since the influence of changing the aperture of the first straight hole 21 on the frequency of the dielectric filter is small, and a certain space is required to be occupied for coupling when processing the circuit on the front surface of the filter body, the aperture of the first straight hole 21 is not too large, preferably, the aperture of the first straight hole 21 is 0.5-1.2mm, and in the present embodiment, the aperture of the first straight hole 21 is 0.8 mm.
In order to maximally change the inductance value of the equivalent circuit of the dielectric filter and to secure the strength of the filter body 10, the diameter of the second straight hole 22 is 2.0mm in the present embodiment.
In order to avoid that the capacitance of the equivalent circuit of the dielectric filter is affected by the too large depth difference between the second straight hole 22 and the first straight hole 21, which results in the decrease of the frequency of the dielectric filter, in this embodiment, the hole depth of the first straight hole 21 is 1mm, and the hole depth of the second straight hole 22 is 2.2 mm.
In this embodiment, there are 5 resonance holes 20, and these 5 resonance holes 20 are parallel and set up with interval along the left and right direction, and for convenient processing, the axial lead of all resonance holes 20 all lies in the coplanar, and the distance between the axial lead of resonance hole 20 and the upper surface and the lower surface of filter body 10 is equal.
As shown in fig. 6-7, the frequency of the dielectric filter in the prior art is about 6500MHz, and under the same size condition, the frequency of the dielectric filter provided by the invention can reach more than 7500MHz, and under the condition that the external dimension of the dielectric filter is not changed, the frequency of the dielectric filter is increased by more than 1000MHz, thereby greatly widening the design range of the frequency of the dielectric filter.
The invention also provides a manufacturing method of the dielectric filter, which comprises the following steps:
a, pressing ceramic powder into a cuboid ceramic block, wherein a resonant hole penetrating through the ceramic block along the front-back direction is reserved in the ceramic block during pressing;
sintering the ceramic block into a filter body;
c, metalizing the filter body, and covering the inner wall surface of the resonance hole and the surface of the filter body with a conductive layer;
d, grinding part of the conductive layer on the front surface of the filter body to form a circuit on the front surface of the filter body, and grinding part of the conductive layer on the upper surface of the filter body to form a signal electrode electrically connected with the circuit on the upper surface of the filter body;
e, mounting a shielding shell to obtain a dielectric filter;
the resonance hole in the step A comprises a first straight hole and a second straight hole which are communicated, the first straight hole is positioned in front of the second straight hole, the axial lead of the first straight hole is coincident with the axial lead of the second straight hole, the distance between the axial lead of the first straight hole and the upper surface and the lower surface of the filter body is equal, the aperture of the second straight hole is larger than that of the first straight hole, the hole depth of the second straight hole is larger than that of the first straight hole and is smaller than or equal to two thirds of the width of the filter body in the front-back direction, and the frequency of the dielectric filter is positively correlated with the hole depth of the second straight hole.
And D, polishing in the step D by adopting a laser polishing mode, so that the conductive layer is good in removing effect, good in flatness after polishing, free of dust and debris, low in cost and high in efficiency.
Preferably, the aperture of the first straight hole is greater than or equal to 0.5mm, the aperture of the second straight hole is greater than or equal to 2 times of the aperture of the first straight hole, and the dielectric filter is also positively correlated with the aperture of the second straight hole.
Further preferably, the dielectric constant of the ceramic powder is greater than 9.
Further preferably, the frequency of the dielectric filter is 7500MHz or more.
The manufacturing method of the dielectric filter provided by the invention is simple to operate, low in processing difficulty, high in yield, suitable for batch production, free of extra cost, high in frequency and good in performance parameter.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The foregoing is directed to embodiments of the present application and it is noted that numerous modifications and adaptations may be made by those skilled in the art without departing from the principles of the present application and are intended to be within the scope of the present application.
Claims (10)
1. A dielectric filter comprising: the filter comprises a filter body, a resonance hole and a conducting layer, wherein the filter body is a cuboid ceramic dielectric block, the resonance hole penetrates through the filter body along the front-back direction, the conducting layer covers the inner wall surface of the resonance hole and the surface of the filter body, the conducting layer covering the front surface of the filter body forms a circuit, and the conducting layer covering the upper surface of the filter body forms a signal electrode electrically connected with the circuit, and the filter is characterized in that:
the resonance hole comprises a first straight hole and a second straight hole which are communicated, the first straight hole is positioned in front of the second straight hole, the aperture of the second straight hole is larger than that of the first straight hole, and the hole depth of the second straight hole is larger than that of the first straight hole.
2. A dielectric filter as recited in claim 1, wherein: the axial lead of the first straight hole is coincident with the axial lead of the second straight hole.
3. A dielectric filter as recited in claim 1, wherein: the aperture of the first straight hole is larger than or equal to 0.5mm, and the aperture of the second straight hole is larger than or equal to 2 times of the aperture of the first straight hole.
4. A dielectric filter as recited in claim 1, wherein: the depth of the second straight hole is less than or equal to two thirds of the width of the filter body in the front-rear direction.
5. A dielectric filter as recited in claim 1, wherein: the resonance holes are arranged in parallel in the left-right direction and are arranged at intervals, and the axial leads of all the resonance holes are positioned on the same plane.
6. A dielectric filter as recited in claim 1, wherein: the distance between the axis of the resonance hole and the upper surface and the lower surface of the filter body is equal.
7. A method for manufacturing a dielectric filter comprises the following steps:
a, pressing ceramic powder into a cuboid ceramic block, wherein a resonance hole penetrating through the ceramic block along the front-back direction is reserved in the ceramic block during pressing;
sintering the ceramic block into a filter body;
c, metalizing the filter body, and covering the inner wall surface of the resonance hole and the surface of the filter body with a conductive layer;
d, grinding part of the conductive layer on the front surface of the filter body to form a circuit on the front surface of the filter body, and grinding part of the conductive layer on the upper surface of the filter body to form a signal electrode electrically connected with the circuit on the upper surface of the filter body;
e, mounting a shielding shell to obtain the dielectric filter;
the method is characterized in that:
the resonance hole comprises a first straight hole and a second straight hole which are communicated with each other in the step A, the first straight hole is located in front of the second straight hole, the axial lead of the first straight hole coincides with the axial lead of the second straight hole, the axial lead of the first straight hole is equal to the distance between the upper surface and the lower surface of the filter body, the aperture of the second straight hole is larger than that of the first straight hole, the hole depth of the second straight hole is larger than that of the first straight hole and is smaller than or equal to two thirds of the width of the filter body in the front-back direction, and the frequency of the dielectric filter is positively correlated with the hole depth of the second straight hole.
8. The method of manufacturing a dielectric filter according to claim 7, wherein: the aperture of the first straight hole is larger than or equal to 0.5mm, the aperture of the second straight hole is larger than or equal to 2 times of the aperture of the first straight hole, and the dielectric filter is also positively correlated with the aperture of the second straight hole.
9. The method of manufacturing a dielectric filter according to claim 7, wherein: the dielectric constant of the ceramic powder is greater than 9.
10. The method of manufacturing a dielectric filter according to claim 7, wherein: the frequency of the dielectric filter is greater than or equal to 7500 MHz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111148702.0A CN113823887A (en) | 2021-09-29 | 2021-09-29 | Dielectric filter and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111148702.0A CN113823887A (en) | 2021-09-29 | 2021-09-29 | Dielectric filter and manufacturing method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113823887A true CN113823887A (en) | 2021-12-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111148702.0A Pending CN113823887A (en) | 2021-09-29 | 2021-09-29 | Dielectric filter and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113823887A (en) |
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2021
- 2021-09-29 CN CN202111148702.0A patent/CN113823887A/en active Pending
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