CN113328222B

CN113328222B - Communication device, dielectric filter, capacitive coupling structure of dielectric filter and design method of dielectric filter

Info

Publication number: CN113328222B
Application number: CN202010129807.0A
Authority: CN
Inventors: 梁梓康; 秦小勇; 邱
Original assignee: Audiowell Electronics Guangdong Co ltd
Current assignee: Audiowell Electronics Guangdong Co ltd
Priority date: 2020-02-28
Filing date: 2020-02-28
Publication date: 2022-08-23
Anticipated expiration: 2040-02-28
Also published as: CN113328222A

Abstract

The invention relates to a communication device, a dielectric filter, a capacitive coupling structure of the dielectric filter and a design method of the capacitive coupling structure. In the production process, on one hand, the deviation between the depth H1 of the capacitive coupling hole and the depth H2 of the frequency modulation hole is within 20 percent, so that the overlarge density difference of the bottom of each hole of a blank body formed by adopting a die in a pressing mode due to the large difference of the hole depths can be avoided, the larger deformation difference of each hole in the blank body firing process can be further avoided, namely, the difference between the depth of the capacitive coupling hole and the depth of the frequency modulation hole is smaller after the firing step and is within a preset range, therefore, the production quality of the product is higher, the size of the die does not need to be adjusted repeatedly, and the production and the manufacture are facilitated; on the other hand, the thickness of the bottom wall of the capacitive coupling hole is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole due to small wall thickness in the blank body firing process can be avoided, and the product quality of the dielectric block obtained by firing the blank body can be ensured.

Description

Communication device, dielectric filter, capacitive coupling structure of dielectric filter and design method of dielectric filter

Technical Field

The invention relates to the technical field of filters, in particular to a communication device, a dielectric filter, a capacitive coupling structure of the dielectric filter and a design method of the dielectric filter.

Background

The dielectric filter is a microwave filter which adopts a dielectric resonant cavity to obtain the frequency-selecting function through multi-stage coupling. The surface of the dielectric filter is covered with a metal layer, and the electromagnetic wave is confined in the dielectric body to form standing wave oscillation. Conventionally, the capacitive coupling structure of a dielectric filter includes a dielectric body. The medium body is provided with two frequency modulation holes and a capacitive coupling hole arranged between the two frequency modulation holes. However, for a narrow band dielectric filter, when the bandwidth of the capacitive coupling needs to be reduced, the depth of the capacitive coupling hole is increased accordingly. However, as the depth of the capacitive coupling hole is larger, for example, the depth of the capacitive coupling hole is generally controlled to be 1.5 times, 2 times or more the depth of the frequency-modulated hole, the thickness of the bottom wall of the capacitive coupling hole will be smaller. Like this, when the medium body sintering shaping, the diapire in capacitive coupling hole takes place deformation easily, leads to not being convenient for process the capacitive coupling hole that forms the compliance with the requirements on the medium body, and product quality can't guarantee, and the production degree of difficulty is great, and production efficiency is lower.

Disclosure of Invention

Therefore, it is necessary to overcome the defects of the prior art, and provide a communication device, a dielectric filter, a capacitive coupling structure thereof and a design method thereof, which are beneficial to ensuring the production quality, facilitating the production and manufacturing, reducing the production difficulty and greatly improving the production efficiency.

The technical scheme is as follows: a capacitive coupling structure for a dielectric filter, comprising: the dielectric block comprises a first surface and a second surface which are oppositely arranged, a capacitive coupling hole is formed in the first surface, two frequency modulation holes which are spaced are formed in one of the surfaces of the first surface and the second surface, the capacitive coupling hole and the frequency modulation holes are blind holes, the capacitive coupling hole is located between the two frequency modulation holes, the depth of the capacitive coupling hole is H1, the depth of each frequency modulation hole is H2, and H1 and H2 meet the following relation: 0.8H2 ≦ H1 ≦ 1.2H 2.

In the production process of the capacitive coupling structure of the dielectric filter, on one hand, the depth H1 of the capacitive coupling hole is closer to the depth H2 of the frequency modulation hole, the deviation is within 20 percent, the phenomenon that the density difference of the bottom of each hole of a green body formed by adopting a die in a pressing mode is overlarge due to large hole depth difference can be avoided, and further, the deformation difference of each hole in the firing process of the green body is large, namely, the fact that the difference between the depth of the capacitive coupling hole and the depth of the frequency modulation hole is smaller after the firing step and is within a preset range can be ensured, so that the production quality of a product is high, the size of the die does not need to be adjusted repeatedly, the production and the manufacture are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole is no longer 1.5 times, 2 times or more than the depth of the frequency modulation hole, that is, the thickness of the bottom wall of the capacitive coupling hole is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole due to small wall thickness in the blank firing process can be avoided, that is, the product quality of the dielectric block obtained by firing the blank can be ensured.

In one embodiment, the distance between two frequency modulation holes is S, the length of the edge where the plane formed by the axes of the two frequency modulation holes intersects with the first surface of the dielectric block is a, and the S and the a satisfy the relationship: s ≧ 0.7A.

In one embodiment, H1 ═ 1.2H2, S ═ 0.7A; alternatively, H1 ═ H2, S ═ 0.75A; alternatively, H1 ═ 0.9H2, S ═ 0.85A; alternatively, H1 ═ 0.85H2, and S ═ 0.9A.

In one embodiment, the S and the a satisfy the relationship: 0.75A ≦ S ≦ 0.85A.

In one embodiment, the distance between the frequency modulation hole and the edge of the dielectric block is D, and D is not less than 0.1 mm.

In one embodiment, the capacitive coupling hole and the frequency modulation hole are both disposed on the first surface. Of course, the capacitive coupling hole may also be provided on a surface other than the tuning hole.

In one embodiment, the capacitive coupling hole comprises a through hole section with a constant inner diameter and a concave part communicated with the through hole section, and the concave part is cylindrical, hemispherical, semi-ellipsoidal or conical.

In one embodiment, the dielectric block is a ceramic block.

A dielectric filter comprises the capacitive coupling structure of the dielectric filter and further comprises a metal layer, wherein the metal layer is plated on the outer wall of the dielectric block, the hole wall of the capacitive coupling hole and the hole wall of the frequency modulation hole.

In the production process of the dielectric filter, on one hand, the depth H1 of the capacitive coupling hole is closer to the depth H2 of the frequency modulation hole, the deviation is within 20%, the phenomenon that the density difference of the bottom of each hole of a green body formed by pressing the mold is overlarge due to large hole depth difference can be avoided, and further, the deformation difference of each hole in the firing process of the green body is large, namely, the fact that the difference between the depth of the capacitive coupling hole and the depth of the frequency modulation hole is smaller and is within a preset range after the firing step can be ensured, so that the production quality of the product is high, the size of the mold does not need to be adjusted repeatedly, the production and the manufacture are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole is no longer 1.5 times, 2 times or more than the depth of the frequency modulation hole, that is, the thickness of the bottom wall of the capacitive coupling hole is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole due to small wall thickness in the blank firing process can be avoided, that is, the product quality of the dielectric block obtained by firing the blank can be ensured.

A communication device comprises the dielectric filter.

In the production process of the communication device, on one hand, the depth H1 of the capacitive coupling hole is closer to the depth H2 of the frequency modulation hole, the deviation is within 20 percent, the overlarge density difference of the bottom of each hole of a blank body formed by pressing the die due to the large difference of the hole depths can be avoided, the large deformation difference of each hole in the blank body firing process can be further avoided, namely, the difference between the depth of the capacitive coupling hole and the depth of the frequency modulation hole after the firing step is smaller and is within a preset range can be ensured, so that the production quality of the product is high, the size of the die does not need to be adjusted repeatedly, the production and the manufacture are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole is no longer 1.5 times, 2 times or more than the depth of the frequency modulation hole, that is, the thickness of the bottom wall of the capacitive coupling hole is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole due to small wall thickness in the blank firing process can be avoided, that is, the product quality of the dielectric block obtained by firing the blank can be ensured.

A method for designing a dielectric filter includes the steps of:

providing raw materials, pressing the raw materials into a blank to be fired through a die, wherein a first processing hole corresponding to the capacitive coupling hole and a second processing hole corresponding to the frequency modulation hole are formed in the blank;

firing the green body to form a capacitive coupling structure of the dielectric filter;

and metal layers are plated on the outer wall of the dielectric block, the hole wall of the capacitive coupling hole and the hole wall of the frequency modulation hole.

In the design method of the dielectric filter, in the production process, on one hand, the depth H1 of the capacitive coupling hole is closer to the depth H2 of the frequency modulation hole, the deviation is within 20 percent, the overlarge density difference of the bottom of each hole of a green body formed by adopting a die to press due to the large difference of the hole depths can be avoided, further, the large deformation difference of each hole in the firing process of the green body can be avoided, namely, the difference between the depth of the capacitive coupling hole and the depth of the frequency modulation hole after the firing step is smaller and is within a preset range can be ensured, so that the production quality of the product is high, the size of the die does not need to be adjusted repeatedly, the production and the manufacture are convenient, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole is no longer, for example, 1.5 times, 2 times or more of the depth of the tuning hole, that is, the thickness of the bottom wall of the capacitive coupling hole is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole due to a small wall thickness in the green body firing process can be avoided, that is, the product quality of the dielectric block obtained by firing the green body can be ensured.

In one embodiment, when the coupling amount of the capacitive coupling structure of the dielectric filter needs to be adjusted, the adjustment is realized by adjusting the distance between the two second machining holes.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a top view of a dielectric filter according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of one embodiment of FIG. 1 at B-B;

FIG. 3 is a cross-sectional view of another embodiment of FIG. 1 at B-B;

FIG. 4 is a cross-sectional view of yet another embodiment of FIG. 1 at B-B;

FIG. 5 is a cross-sectional view of still another embodiment of FIG. 1 at B-B;

fig. 6 is a graph of S-parameter of a capacitive coupling structure of a dielectric filter according to an embodiment of the invention.

Reference numerals:

10. a dielectric block; 11. a first surface; 12. a second surface; 13. a capacitive coupling aperture; 131. a straight-through hole section; 132. a recess; 14. and (4) frequency modulation holes.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the description of the present invention, it should be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly connected" to another element, there are no intervening elements present.

In one embodiment, referring to fig. 1 and 2, a capacitive coupling structure of a dielectric filter includes a dielectric block 10. The dielectric block 10 includes a first surface 11 and a second surface 12 disposed opposite to each other. The first surface 11 is provided with a capacitive coupling hole 13, and one of the first surface 11 and the second surface 12 is provided with two frequency modulation holes 14 at intervals. The capacitive coupling hole 13 and the frequency modulation hole 14 are both blind holes, and the capacitive coupling hole 13 is located between the two frequency modulation holes 14. The depth of the capacitive coupling hole 13 is H1, the depth of the frequency modulation hole 14 is H2, and the H1 and the H2 satisfy the following relation: 0.8H2 ≦ H1 ≦ 1.2H 2.

In the production process of the capacitive coupling structure of the dielectric filter, on one hand, the depth H1 of the capacitive coupling hole 13 is closer to the depth H2 of the frequency modulation hole 14, and the deviation is within 20 percent, so that the excessive density difference of the bottom of each hole of a blank formed by pressing the mold due to the large difference of the hole depths can be avoided, and further the large deformation difference of each hole in the firing process of the blank can be avoided, namely the difference between the depth of the capacitive coupling hole 13 and the depth of the frequency modulation hole 14 after the firing step is smaller and within a preset range can be ensured, so that the production quality of the product is high, the size of the mold does not need to be adjusted repeatedly, the production and the manufacturing are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole 13 is no longer 1.5 times, 2 times or more than the depth of the tuning hole 14, that is, the thickness of the bottom wall of the capacitive coupling hole 13 is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole 13 due to a small wall thickness during the firing of the green body can be avoided, that is, the product quality of the dielectric block 10 obtained by firing the green body can be ensured.

It should be noted that the depths of the two tuning holes 14 may be the same or different. When the depths of the two fm holes 14 are different, the depth of the fm hole 14 with the shallower depth is not less than 0.8 times the depth of the fm hole 14 with the deeper depth. The depth of the frequency modulation hole 14 is determined according to the frequency design of the actual product, and the specific ratio relation is not limited herein.

Further, referring to fig. 1 and fig. 2, a distance between the two tuning holes 14 is S, a length of an edge where a plane formed by axes of the two tuning holes 14 intersects with the first surface 11 of the dielectric block 10 is a, and S and a satisfy a relationship: s ≧ 0.7A. Wherein, when the depth of the capacitive coupling hole 13 is reduced, the coupling amount of the capacitive coupling structure of the dielectric filter becomes large; when the size of the space S of the two tuning holes 14 is increased, the amount of coupling of the capacitive coupling structure of the dielectric filter becomes small. Thus, the distance S between the two frequency modulation holes 14 is larger than that of a conventional dielectric filter, so that the coupling amount of the capacitive coupling structure of the dielectric filter can be reduced, and the increased coupling amount caused by the reduction of the depth of the capacitive coupling hole 13 can be offset, so that the coupling amount of the capacitive coupling structure of the dielectric filter is in a balanced state, and the requirements of customers are met.

Referring to fig. 6, fig. 6 is a S-parameter graph of a capacitive coupling structure of a dielectric filter under a 6-cavity double-zero-point symmetric structure according to an embodiment of the present invention, and it can be seen from fig. 6 that the heights of the two symmetrical zero points approach to balance, and if the balance degree of the symmetrical zero points needs to be adjusted, the balance degree is achieved by adjusting the design of the cavity arrangement structure, or by adjusting the distance between two frequency modulation holes 14, or by adjusting the depth of the capacitive coupling hole 13. As can be seen from fig. 6, when the capacitive coupling bandwidth ranges from 3.4GHZ to 3.6GHZ, the transmission losses S2 are all 0 and are in a horizontal straight line, and at this time, the return loss S1 has a relatively large attenuation amount; when the capacitive coupling bandwidth is less than 3.4GHZ or more than 3.6GHZ, the transmission loss S2 has a large attenuation and corresponds to a zero point, and at this time, the attenuation of the return loss S1 is 0 and is in a horizontal straight line. Therefore, when the depth of the capacitive coupling hole 13 is reduced and the size of the distance S between the two frequency modulation holes 14 is increased, the coupling quantity of the capacitive coupling structure of the dielectric filter is still in a preset requirement, the performance of the dielectric filter in a narrow frequency band (for example, the range of the capacitive coupling bandwidth is 3.4GHZ-3.6GHZ) can meet the requirement, meanwhile, the product can avoid larger deformation difference of each hole in the blank body firing process, namely, the difference between the depth of the capacitive coupling hole 13 and the depth of the frequency modulation hole 14 after the firing step is smaller and in the preset range, so that the product has higher production quality, the size of a die does not need to be adjusted repeatedly, the production and the manufacturing are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved.

It is to be understood that the dielectric filter is not limited to a dielectric filter with a 6-cavity double-zero symmetric structure, but may also be a dielectric filter with a 4-cavity double-zero symmetric structure, a dielectric filter with an 8-cavity double-zero symmetric structure, a dielectric filter with a 16-cavity double-zero symmetric structure, or the like, and is not limited herein.

In one embodiment, the H1 ═ 1.2H2, S ═ 0.7A; alternatively, H1 ═ H2, S ═ 0.75A; alternatively, H1 ═ 0.9H2, S ═ 0.85A; alternatively, H1 ═ 0.85H2 and S ═ 0.9A.

Further, the S and the a satisfy the relationship: 0.75A ≦ S ≦ 0.85A. Therefore, on one hand, the coupling quantity of the capacitive coupling structure of the dielectric filter can be in a balanced state, and the requirements of customers are met; on the other hand, the distance between the tuning holes 14 and the plate edges of the dielectric block 10 is large enough not to cause quality problems of product deformation in the blank body in the firing step because the distance is too small.

In one embodiment, the distance between the frequency modulation hole 14 and the edge of the dielectric block 10 is D, and D is not less than 0.1 mm. Specifically, the size of D is determined according to the actual size of the dielectric block 10, and is generally, for example, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, but not limited thereto. In this way, the distance between the tuning holes 14 and the plate edges of the dielectric block 10 is large enough not to cause quality problems of product deformation during the firing step of the blank because the distance is too small.

In one embodiment, the capacitive coupling hole 13 and the frequency tuning hole 14 are both disposed on the first surface 11. Of course, the capacitive coupling hole 13 may be provided on a surface different from the tuning hole 14.

In one embodiment, referring to fig. 2 to 5, the capacitive coupling hole 13 includes a through hole section 131 with a constant inner diameter and a concave portion 132 communicating with the through hole section 131, wherein the concave portion 132 is cylindrical, hemispherical, semi-ellipsoidal or conical.

Further, the dielectric block 10 is a ceramic block.

In an embodiment, referring to fig. 1 again, a dielectric filter includes the capacitive coupling structure of the dielectric filter according to any one of the above embodiments, and further includes a metal layer. The metal layer is arranged on the outer wall of the dielectric block 10, the hole wall of the capacitive coupling hole 13 and the hole wall of the frequency modulation hole 14.

In the production process of the dielectric filter, on one hand, the depth H1 of the capacitive coupling hole 13 is closer to the depth H2 of the frequency modulation hole 14, and the deviation is within 20%, so that the phenomenon that the density difference of the bottom of each hole of a green body formed by pressing the mold is overlarge due to large hole depth difference can be avoided, and further, the deformation difference of each hole in the firing process of the green body is large, namely, the difference between the depth of the capacitive coupling hole 13 and the depth of the frequency modulation hole 14 after the firing step is smaller and is within a preset range can be ensured, so that the production quality of the product is high, the size of the mold does not need to be adjusted repeatedly, the production and the manufacture are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole 13 is no longer, for example, 1.5 times, 2 times or more of the depth of the tuning hole 14, that is, the thickness of the bottom wall of the capacitive coupling hole 13 is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole 13 due to a small wall thickness in the blank firing process can be avoided, that is, the product quality of the dielectric block 10 obtained by firing the blank can be ensured.

In one embodiment, the metal layer is a silver layer, a copper layer, a tin layer, a platinum layer or a gold layer plated, sprayed or adhered on the surface of the dielectric block 10.

In one embodiment, a communication device includes the dielectric filter according to any one of the above embodiments.

Since the communication device includes the dielectric filter, the technical effect of the communication device is brought by the dielectric filter, and the beneficial effect is the same as that of the dielectric filter, which is not described herein again.

In one embodiment, a method for designing a dielectric filter includes the steps of:

step S100, providing raw materials, pressing the raw materials into a blank to be fired through a mold, wherein a first machining hole corresponding to the capacitive coupling hole 13 and a second machining hole corresponding to the frequency modulation hole 14 are formed in the blank;

the raw material is, for example, clay or china clay. Placing pottery clay or porcelain clay into a mould to be pressed to obtain a blank. During the pressing process, a first machined hole corresponding to the capacitive coupling hole 13 and a second machined hole corresponding to the tuning hole 14 may be formed in the blank. And the depth deviation of the first machined hole and the depth deviation of the second machined hole are smaller, so that the density difference between the hole wall structure of the first machined hole and the hole wall structure of the second machined hole on the blank body is smaller.

Step S200, firing the blank to form a capacitive coupling structure of the dielectric filter according to any of the above embodiments;

the density difference between the hole wall structure of the first processing hole and the hole wall structure of the second processing hole on the blank body is small, so that the depth of the capacitive coupling hole 13 of the product of the dielectric block 10 obtained by firing the blank body is close to the deformation of the frequency modulation hole 14, and the depth difference between the capacitive coupling hole 13 and the frequency modulation hole 14 is small, so that the production quality of the product is high, the size of a die does not need to be adjusted repeatedly for repeated pressing, firing and testing, the production and manufacturing can be facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved.

And step S300, plating metal layers on the outer wall of the dielectric block 10, the hole wall of the capacitive coupling hole 13 and the hole wall of the frequency modulation hole 14.

In the design method of the dielectric filter, in the production process, on one hand, the depth H1 of the capacitive coupling hole 13 is closer to the depth H2 of the frequency modulation hole 14, and the deviation is within 20 percent, so that the excessive density difference of the bottom of each hole of a blank formed by pressing the mold due to the large difference of the hole depths can be avoided, and further the large deformation difference of each hole in the blank firing process can be avoided, namely the small difference between the depth of the capacitive coupling hole 13 and the depth of the frequency modulation hole 14 after the firing step and the preset range can be ensured, therefore, the production quality of the product is high, the size of the mold does not need to be adjusted repeatedly, the production and the manufacturing are facilitated, the production difficulty is reduced, and the production efficiency can be greatly improved; on the other hand, the depth H1 of the capacitive coupling hole 13 is no longer, for example, 1.5 times, 2 times or more of the depth of the tuning hole 14, that is, the thickness of the bottom wall of the capacitive coupling hole 13 is relatively increased, so that the problem of deformation quality of the bottom wall of the capacitive coupling hole 13 due to a small wall thickness in the blank firing process can be avoided, that is, the product quality of the dielectric block 10 obtained by firing the blank can be ensured.

Further, when the coupling amount of the capacitive coupling structure of the dielectric filter needs to be adjusted, in step S100, the adjustment is performed by adjusting the distance between the two second machining holes. Specifically, if the coupling amount of the capacitive coupling structure of the dielectric filter is too large, in step S100, on one hand, the distance between two second machining holes is increased, or the depth of the first machining hole is correspondingly increased; on the contrary, if the coupling amount of the capacitive coupling structure of the dielectric filter is smaller, in step S100, on one hand, the distance between the two second machining holes is reduced, or the depth of the first machining hole is correspondingly reduced. Therefore, the coupling quantity of the capacitive coupling structure of the dielectric filter can be adjusted to meet the preset requirement.

Wherein the depth of the first machining hole is h1, the depth of the second machining hole is h2, and the h1 and the h2 satisfy the relation: 0.8h2 ≦ h1 ≦ 1.2h 2. Thus, after the blank is fired to obtain the dielectric block 10, the following effects can be achieved: the depth of the capacitive coupling hole 13 is H1, the depth of the frequency modulation hole 14 is H2, and the H1 and the H2 satisfy the following relation: 0.8H2 ≦ H1 ≦ 1.2H 2.

Further, the distance between the two second machining holes is s, the length of the edge of the plane formed by the axes of the two second machining holes, which intersects with the first surface 11 of the blank, is a, and the s and the a satisfy the relationship: s ≧ 0.7 a.

Further, h1 ═ 1.2h2, s ═ 0.7 a; alternatively, h 1-h 2, s-0.75 a; alternatively, h1 ═ 0.9h2, s ═ 0.85 a; alternatively, h1 is 0.85h2 and S is 0.9 a.

Further, s and a satisfy the relationship: 0.75a ≦ s ≦ 0.85 a. Therefore, on one hand, the coupling quantity of the capacitive coupling structure of the dielectric filter can be in a balanced state, and the requirements of customers are met; on the other hand, the distance between the tuning holes 14 and the plate edges of the dielectric block 10 is large enough not to cause quality problems of product deformation in the blank body in the firing step because the distance is too small.

In one embodiment, the second machining hole is spaced from the edge of the blank by a distance d, which is not less than 0.1 mm. Specifically, the size of d is determined according to the actual size of the dielectric block 10, and is generally, for example, 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, or 0.4mm, but not limited thereto. Therefore, the distance between the second machining hole and the plate edge of the blank is large enough, and the quality problem of product deformation in the firing step of the blank due to too small distance is avoided.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A capacitive coupling structure of a dielectric filter is characterized in that the dielectric filter is a four-cavity double-zero-point symmetrical dielectric filter, a six-cavity double-zero-point symmetrical dielectric filter, an eight-cavity double-zero-point symmetrical dielectric filter or a sixteen-cavity double-zero-point symmetrical dielectric filter, and the capacitive coupling structure of the dielectric filter comprises:

the dielectric block comprises a first surface and a second surface which are oppositely arranged, a capacitive coupling hole is formed in the first surface, two frequency modulation holes which are spaced are formed in one of the surfaces of the first surface and the second surface, the capacitive coupling hole and the frequency modulation holes are blind holes, the capacitive coupling hole is located between the two frequency modulation holes, the depth of the capacitive coupling hole is H1, the depth of each frequency modulation hole is H2, and H1 and H2 meet the following relation: 0.8H2 ≦ H1 ≦ H2; the distance between the two frequency modulation holes is S, the length of an edge, intersected with the first surface of the dielectric block, of a plane formed by the axes of the two frequency modulation holes is A, and the S and the A meet the following relation: s ≧ 0.75A.

2. The capacitive coupling structure of a dielectric filter according to claim 1, wherein H1 ═ H2, S ═ 0.75A; alternatively, H1 ═ 0.9H2, S ═ 0.85A; alternatively, H1 ═ 0.85H2, and S ═ 0.9A.

3. The capacitive coupling structure of a dielectric filter according to claim 1, wherein S and a satisfy a relationship: 0.75A ≦ S ≦ 0.85A.

4. The capacitive coupling structure of a dielectric filter according to any one of claims 1 to 3, wherein the frequency-modulation holes are spaced from the edges of the dielectric block by a distance D, which is not less than 0.1 mm.

5. The capacitive coupling structure of a dielectric filter of claim 1, wherein the capacitive coupling hole and the frequency modulation hole are both disposed on the first surface.

6. The capacitive coupling structure of a dielectric filter according to claim 1, wherein the capacitive coupling hole includes a through hole section having a constant inner diameter and a concave section communicating with the through hole section, the concave section being cylindrical, hemispherical, semi-ellipsoidal or conical.

7. The capacitive coupling structure of a dielectric filter as claimed in any one of claims 1 to 3, wherein the dielectric block is a ceramic block.

8. A dielectric filter, comprising the capacitive coupling structure of a dielectric filter according to any one of claims 1 to 7, further comprising a metal layer, wherein the metal layer is plated on the outer wall of the dielectric block, the hole wall of the capacitive coupling hole, and the hole wall of the frequency modulation hole.

9. A communication device comprising a dielectric filter according to claim 8.

10. A method for designing a dielectric filter, comprising the steps of:

providing a raw material, pressing the raw material into a blank to be fired through a die, wherein a first processing hole corresponding to the capacitive coupling hole and a second processing hole corresponding to the frequency modulation hole are formed in the blank;

firing the green body to form a capacitive coupling structure of the dielectric filter according to any one of claims 1 to 7;

11. The method as claimed in claim 10, wherein the step of adjusting the distance between the two second holes is performed when the coupling amount of the capacitive coupling structure of the dielectric filter is required to be adjusted.