阅读说明：本技术 介质滤波器的容性耦合结构、平衡度调节方法及滤波器 (Capacitive coupling structure of dielectric filter, balance degree adjusting method and filter ) 是由 谢懿非 欧阳洲 丁海 林显添 邸英杰 于 2019-09-30 设计创作，主要内容包括：本发明涉及一种介质滤波器的容性耦合结构、平衡度调节方法及滤波器,介质滤波器的容性耦合结构包括介质块与金属层。所述介质块包括相对设置的第一表面与第二表面。所述第一表面上设有耦合通孔。一方面,通过调整封闭式环形缺口在锥形孔段的孔壁上的设置位置,即改变封闭式环形缺口与耦合通孔的孔径较大的一端端面之间的间距H0时,便能相应调整对称零点的平衡度；另一方面,由于耦合通孔包括锥形孔段,相对于孔壁垂直于第一表面的直通孔而言,锥形孔段的孔壁倾斜设置,这样既便于将金属层形成于耦合通孔的孔壁上,又方便采用切割工具(包括刀具与激光等等)在锥形孔段的金属层上开设出封闭式环形缺口,进而能提高生产效率。(The invention relates to a capacitive coupling structure of a dielectric filter, a balance degree adjusting method and the filter. The dielectric block comprises a first surface and a second surface which are oppositely arranged. The first surface is provided with a coupling through hole. On one hand, the balance degree of the symmetrical zero point can be correspondingly adjusted by adjusting the arrangement position of the closed annular notch on the hole wall of the conical hole section, namely changing the distance H0 between the closed annular notch and the end face of the coupling through hole with larger hole diameter at one end; on the other hand, the coupling through hole comprises the conical hole section, and compared with a straight-through hole with the hole wall perpendicular to the first surface, the hole wall of the conical hole section is obliquely arranged, so that the metal layer is conveniently formed on the hole wall of the coupling through hole, a closed annular notch is conveniently formed in the metal layer of the conical hole section by adopting a cutting tool (comprising a cutter, laser and the like), and further the production efficiency can be improved.)

1. A capacitive coupling structure for a dielectric filter, comprising:

the dielectric block comprises a first surface and a second surface which are oppositely arranged, the first surface is provided with a coupling through hole, the coupling through hole extends from the first surface to the second surface, and the coupling through hole comprises a conical hole section with gradually increased inner diameter;

the metal layer is laid on the outer wall of the dielectric block and the hole wall of the coupling through hole, and a closed annular notch is formed in the metal layer on the hole wall of the conical hole section.

2. The capacitive coupling structure of a dielectric filter according to claim 1, wherein at least one of the metal layer of the wall of the coupling via, the metal layer of the first surface, and the metal layer of the second surface is provided with a non-closed annular gap disposed around the coupling via.

3. The capacitive coupling structure of a dielectric filter according to claim 2, wherein the non-closed annular notch includes a first end and a second end opposite to each other, the first end and the second end are spaced apart from each other, a line connecting the first end to the axis of the coupling through hole is a first boundary line, a line connecting the second end to the axis of the coupling through hole is a second boundary line, an included angle β between the first boundary line and the second boundary line is β, and 0 ° < β <360 °.

4. The capacitive coupling structure of a dielectric filter according to claim 2, wherein the number of the closed-type annular gaps is two or more, and the two or more closed-type annular gaps are arranged at intervals along an axial direction of the coupling through hole; the number of the non-closed annular gaps is more than two, and the non-closed annular gaps are arranged at intervals along the axial direction of the coupling through hole.

5. The capacitive coupling structure of a dielectric filter according to claim 1, wherein said coupling via further comprises a through hole section having a constant inner diameter size, said through hole section communicating with said tapered hole section.

6. The capacitive coupling structure of a dielectric filter of claim 5, wherein there are two through-hole sections, wherein one end of one through-hole section is in butt-joint communication with one end of the tapered hole section, and the other end of the through-hole section is in butt-joint communication with the other end of the tapered hole section.

7. The capacitive coupling structure of a dielectric filter according to claim 5, wherein the angle between the hole wall of the tapered hole section and the axis of the coupling through hole is a, and 5 ° < a <85 °.

8. The capacitive coupling structure of a dielectric filter according to any one of claims 1 to 7, wherein the first surface further has two spaced resonant holes, the coupling via is located between the two resonant holes, and the metal layer is further laid on the walls of the resonant holes.

9. A method for adjusting the degree of balance of a dielectric filter, wherein the capacitive coupling structure of a dielectric filter according to any one of claims 1 to 8 is used, comprising the steps of:

the balance degree of the symmetrical zero point is correspondingly adjusted by changing the distance H0 between the closed annular notch and the end face of the end with the larger aperture of the coupling through hole.

10. A filter comprising a capacitive coupling structure of a dielectric filter according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of filters, in particular to a capacitive coupling structure of a dielectric filter, a balance adjusting method and the 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 degree of symmetrical zero balance is generally adjusted by changing the cavity design of the dielectric filter. However, when the cavity arrangement structure is designed again, on one hand, the workload of cavity arrangement design is increased, the difficulty of cavity arrangement design is high, and on the other hand, after the cavity arrangement structure is changed, the performance index of the dielectric filter is seriously affected. Therefore, the adjustment of the symmetrical zero balance degree of the capacitive coupling structure of the dielectric filter is quite difficult, so that the production efficiency is low, and the application of the dielectric filter is finally greatly limited.

Disclosure of Invention

Therefore, it is necessary to overcome the defects of the prior art and provide a capacitive coupling structure of a dielectric filter, a balance degree adjusting method and a filter, which can facilitate the adjustment of the balance degree of the symmetrical zero point and greatly improve 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, the first surface is provided with a coupling through hole, the coupling through hole extends from the first surface to the second surface, and the coupling through hole comprises a conical hole section with gradually increased inner diameter; the metal layer is laid on the outer wall of the dielectric block and the hole wall of the coupling through hole, and a closed annular notch is formed in the metal layer on the hole wall of the conical hole section.

On one hand, the capacitive coupling structure of the dielectric filter can correspondingly adjust the balance degree of the symmetrical zero point by adjusting the arrangement position of the closed annular notch on the hole wall of the conical hole section, namely changing the distance H0 between the closed annular notch and the end face of the coupling through hole with the larger hole diameter at one end; on the other hand, the coupling through hole comprises the conical hole section, and compared with a straight-through hole with the hole wall perpendicular to the first surface, the hole wall of the conical hole section is obliquely arranged, so that the metal layer is conveniently formed on the hole wall of the coupling through hole, a closed annular notch is conveniently formed in the metal layer of the conical hole section by adopting a cutting tool (comprising a cutter, laser and the like), and further the production efficiency can be improved. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

In one embodiment, at least one of the metal layer of the hole wall of the coupling through hole, the metal layer of the first surface and the metal layer of the second surface is provided with a non-closed annular notch arranged around the coupling through hole.

In one embodiment, the non-closed annular notch includes a first end and a second end opposite to each other, the first end and the second end are spaced apart from each other, a line connecting the first end to the axis of the coupling through hole is a first boundary line, a line connecting the second end to the axis of the coupling through hole is a second boundary line, an included angle between the first boundary line and the second boundary line is β, and 0 ° < β <360 °.

In one embodiment, the number of the closed annular gaps is two or more, and the two or more closed annular gaps are arranged at intervals along the axial direction of the coupling through hole; the number of the non-closed annular gaps is more than two, and the non-closed annular gaps are arranged at intervals along the axial direction of the coupling through hole.

In one embodiment, the coupling via further comprises a through hole section with a constant inner diameter, and the through hole section is communicated with the conical hole section.

In one embodiment, the number of the through hole sections is two, wherein the end part of one through hole section is in butt joint communication with one end of the taper hole section, and the end part of the other through hole section is in butt joint communication with the other end of the taper hole section.

In one embodiment, the angle between the hole wall of the conical hole section and the axis of the coupling through hole is a, and 5 ° < a <85 °.

In one embodiment, the first surface is further provided with two spaced resonant holes, the coupling through hole is positioned between the two resonant holes, and the metal layer is further laid on the hole walls of the resonant holes.

A method for adjusting the balance degree of a dielectric filter adopts a capacitive coupling structure of the dielectric filter, and comprises the following steps: the balance degree of the symmetrical zero point is correspondingly adjusted by changing the distance H0 between the closed annular notch and the end face of the end with the larger aperture of the coupling through hole.

On one hand, the balance degree of the symmetrical zero point can be correspondingly adjusted by adjusting the arrangement position of the closed annular notch on the hole wall of the conical hole section, namely changing the distance H0 between the closed annular notch and the end face of the coupling through hole with the larger aperture at one end; on the other hand, the coupling through hole comprises the conical hole section, and compared with a straight-through hole with the hole wall perpendicular to the first surface, the hole wall of the conical hole section is obliquely arranged, so that the metal layer is conveniently formed on the hole wall of the coupling through hole, a closed annular notch is conveniently formed in the metal layer of the conical hole section by adopting a cutting tool (comprising a cutter, laser and the like), and further the production efficiency can be improved. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

A filter comprises the capacitive coupling structure of the dielectric filter.

On one hand, the filter can correspondingly adjust the balance degree of the symmetrical zero point by adjusting the arrangement position of the closed annular notch on the hole wall of the conical hole section, namely changing the distance H0 between the closed annular notch and the end face of the coupling through hole with the larger hole diameter at one end; on the other hand, the coupling through hole comprises the conical hole section, and compared with a straight-through hole with the hole wall perpendicular to the first surface, the hole wall of the conical hole section is obliquely arranged, so that the metal layer is conveniently formed on the hole wall of the coupling through hole, a closed annular notch is conveniently formed in the metal layer of the conical hole section by adopting a cutting tool (comprising a cutter, laser and the like), and further the production efficiency can be improved. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

Drawings

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

FIG. 2 is a cross-sectional view at A-A of FIG. 1;

fig. 3 is a top view of a capacitive coupling structure of a dielectric filter according to another embodiment of the present invention;

FIG. 4 is a cross-sectional view at A-A of FIG. 3;

fig. 5 is a top view of a capacitive coupling structure of a dielectric filter according to another embodiment of the present invention;

FIG. 6 is a cross-sectional view of one embodiment of FIG. 5 at A-A;

fig. 7 is a bottom view of a capacitive coupling structure of a dielectric filter according to still another embodiment of the present invention;

FIG. 8 is a cross-sectional view of another embodiment of FIG. 5 at A-A;

FIG. 9 is a cross-sectional view of the further embodiment of FIG. 5 at A-A;

fig. 10 is a schematic structural diagram of a dielectric filter according to an embodiment of the present invention;

fig. 11 is a graph of the S-parameter of the capacitive coupling structure of the conventional dielectric filter;

fig. 12 is a graph of S-parameter when H0 is 2mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 13 is a graph of S-parameter when H0 is 1.55mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 14 is a graph of S-parameter when H0 is 1.5mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 15 is a graph of S-parameter when H0 is 1.4mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 16 is a graph of S-parameter when H0 is 1.35mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 17 is a graph of S-parameter when H0 is 1.0mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

fig. 18 is a graph showing an S-parameter when H0 is 4.5mm in a capacitive coupling structure of a dielectric filter according to another embodiment of the present invention;

fig. 19 is a graph showing an S-parameter curve when H0 is 3mm in a capacitive coupling structure of a dielectric filter according to another embodiment of the present invention;

fig. 20 is a graph of S-parameter when H0 is 1.17mm in the capacitive coupling structure of the dielectric filter according to another embodiment of the present invention.

Reference numerals:

10. a dielectric block; 11. a first surface; 12. a second surface; 13. a coupling via; 131. a tapered bore section; 132. a straight-through hole section; 133. the hole wall is inclined by 45 degrees; 14. a closed annular gap; 15. a non-closed annular gap; 151. a first boundary line; 152. a second boundary line; 16. a resonant aperture; 20. a metal layer.

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 such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited 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 and a metal layer 20. 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 coupling through hole 13. The coupling through hole 13 extends from the first surface 11 to the second surface 12, and the coupling through hole 13 includes a tapered hole section 131 with an inner diameter gradually increasing. The metal layer 20 is laid on the outer wall of the dielectric block 10 and the hole wall of the coupling through hole 13, and a closed annular gap 14 is formed in the metal layer 20 on the hole wall of the conical hole section 131.

On one hand, the capacitive coupling structure of the dielectric filter can correspondingly adjust the balance degree of the symmetrical zero point by adjusting the arrangement position of the closed annular notch 14 on the hole wall of the conical hole section 131, namely changing the distance H0 between the closed annular notch 14 and the end face of the coupling through hole 13 with the larger hole diameter at one end; on the other hand, since the coupling through-hole 13 includes the tapered hole section 131, compared with a through-hole having a hole wall perpendicular to the first surface 11, the hole wall of the tapered hole section 131 is inclined, which not only facilitates forming the metal layer 20 on the hole wall of the coupling through-hole 13, but also facilitates forming the closed annular gap 14 on the metal layer 20 of the tapered hole section 131 by using a cutting tool (including a cutter, a laser, etc.), thereby improving the production efficiency. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

It should be explained that both ends of the closed annular gap 14 communicate with each other, forming, for example, a closed form circular ring shape, a closed form square ring shape, or a closed form oval ring shape. The non-closed annular gap 1514 has opposite ends, and the opposite ends of the non-closed annular gap 1514 are spaced from each other and are not in communication with each other, that is, the non-closed annular gap 1514 is, for example, a non-closed circular ring, a non-closed square ring, or a non-closed elliptical ring. In addition, the metal layer 20 is not laid at the closed annular gap 14 and the non-closed annular gap 1514, and the wall surface of the dielectric block 10 is exposed. Specifically, the metal layer 20 at the closed annular gap 14 and the non-closed annular gap 1514 is exposed on the wall surface of the dielectric block 10 by removing or etching, but of course, the wall surface of the dielectric block 10 corresponding to the closed annular gap 14 and the non-closed annular gap 1514 may be exposed without plating or spraying the metal layer 20.

Specific examples of the dielectric block 10 include a ceramic dielectric block, and specific examples of the metal layer 20 include a silver layer and a copper layer, but are not limited thereto.

In one embodiment, referring to fig. 2 again, the metal layer 20 on the wall of the coupling via 13 is provided with an unsealed annular gap 1514. Thus, on the one hand, under the condition that the capacitive coupling bandwidth of the dielectric filter is ensured to reach the preset value, after the non-closed annular notch 1514 is arranged on the metal layer 20 on the hole wall of the coupling through hole 13, the width of the closed annular notch 14 can be increased to a certain extent, for example, the width of the closed annular notch 14 is increased from 0.1mm to 1mm or 2mm, and the closed annular notch 14 with the width of more than 1mm can be conveniently machined by a cutter, even if the closed annular notch 14 is formed on the hole wall of the conical hole section 131; on the other hand, an open-type annular gap 1514 is provided in the metal layer 20 on the hole wall of the coupling via 13, and the open-type annular gap 1514 can be used to adjust the capacitive coupling bandwidth of the dielectric filter. It should be noted that the opening position of the non-closed annular gap 1514 on the hole wall of the coupling through hole 13 is not limited.

In another embodiment, referring to fig. 5 to 7, an unsealed annular gap 1514 disposed around the coupling via 13 is disposed on one of the first surface 11 and the second surface 12. In this way, the non-closed annular gap 1514 may be formed on the first surface 11 or the second surface 12 and disposed around the coupling through hole 13, which facilitates manufacturing compared with forming the non-closed annular gap 1514 on the hole wall of the coupling through hole 13.

Further, referring to fig. 5-7, the unsealed annular gap 1514 includes opposing first and second ends. The first end and the second end are arranged at an interval, a connecting line from the first end to the axis of the coupling through hole 13 is a first boundary line 151, a connecting line from the second end to the axis of the coupling through hole 13 is a second boundary line 152, an included angle between the first boundary line 151 and the second boundary line 152 is β, and 0 ° < β <360 °. In this way, along the length direction of the non-closed annular gap 1514, the non-closed annular gap 1514 extends from a first end to a second end, and the first end and the second end are arranged at intervals, so that the non-closed annular gap 1514 is arranged around part of the circumference of the coupling through hole 13 instead of completely around the circumference of the coupling through hole 13. Meanwhile, the capacitive coupling bandwidth can be adjusted by adjusting the included angle β between the first boundary line 151 and the second boundary line 152, and when the angle β changes, the width and the width of the capacitive coupling bandwidth change accordingly. β may be 45 °, 90 °, 135 °, 180 °, 225 °, 250 °, 300 °, or other angle that enables the non-enclosed annular gap 1514 to interfit with the enclosed annular gap 14 to adjust the capacitive coupling bandwidth.

As a solution of phase change from the above embodiment, the number of the closed annular gaps 14 is two or more, and the two or more closed annular gaps 14 are arranged at intervals along the axial direction of the coupling through hole 13.

As a solution of phase change from the above embodiment, the number of the non-closed annular gaps 1514 is two or more, and the two or more non-closed annular gaps 1514 are arranged at intervals along the axial direction of the coupling through hole 13.

Alternatively, the closed annular gap 14 and the non-closed annular gap 1514 may be one each.

In one embodiment, referring to fig. 5, 8 and 9, the coupling through hole 13 further includes a through hole section 132 with a constant inner diameter, and the through hole section 132 is communicated with the tapered hole section 131.

In one embodiment, there are two through hole sections 132, wherein an end of one through hole section 132 is in butt communication with one end of the tapered hole section 131, and an end of the other through hole section 132 is in butt communication with the other end of the tapered hole section 131.

As an optional scheme, the tapered hole section 131 may be one tapered hole section 131, or may be formed by sequentially communicating two or more tapered hole sections 131 with different hole wall inclinations, or may be formed by combining two or more tapered hole sections 131 with one or more through hole sections, as long as the hole diameter of the tapered hole section 131 satisfies a tendency of gradually increasing from one end to the other end or gradually increasing as a whole.

As an alternative, the through hole section 132 is one, and the through hole section 132 and the tapered hole section 131 are communicated with each other to form the coupling through hole 13.

As an optional scheme, the coupling through hole 13 does not include the through hole section 132, and the coupling through hole 13 is the tapered hole section 131, so that the coupling through hole 13 does not need to be provided with the through hole section 132, and a tapered hole is directly formed on the dielectric block 10, so that the manufacturing and processing are convenient.

In one embodiment, the angle between the hole wall of the conical hole section 131 and the axis of the coupling through hole 13 is a, and 5 ° < a <85 °. Further, 15 ° < a <75 °.

Specifically, the angle between the hole wall of the conical hole section 131 and the axis of the coupling through hole 13 is 45 degrees. Therefore, on one hand, the metal layer 20 can be conveniently paved and formed on the hole wall of the coupling through hole 13, and on the other hand, the metal layer 20 on the hole wall of the coupling through hole 13 can be conveniently provided with the closed annular notch 14 and the non-closed annular notch 1514 by adopting a cutting tool (comprising a cutter, a laser and the like), so that the production efficiency can be improved.

As an alternative, the included angle a between the hole wall of the tapered hole section 131 and the axis of the coupling through hole 13 is not limited to 5 ° to 85 °, and a may be in a range greater than 0 ° and less than 90 °.

In one embodiment, the wall of the mouth of the coupling through-hole 13 is chamfered or filleted. Specifically, referring to fig. 6, 8 and 9, the hole wall of the mouth of the coupling through hole 13 is, for example, a 45-degree inclined hole wall 133.

Further, in order to increase the angle between the hole wall of the conical hole section 131 and the axis of the coupling through hole 13, and at the same time, in order to not change the diameter of the mouth of the coupling through hole 13 as much as possible, the length H2 of the through hole section 132 adjacent to the mouth with smaller inner diameter of the conical hole section 131 may be increased accordingly, so that the angle between the hole wall of the conical hole section 131 and the axis of the coupling through hole 13 may be increased accordingly.

In one embodiment, referring to fig. 1 and fig. 2 again, the first surface 11 is further provided with two spaced resonant holes 16, the coupling via 13 is located between the two resonant holes 16, and the metal layer 20 is further laid on the hole walls of the resonant holes 16.

Further, referring to fig. 6, 8 and 9, similar to the design of the hole wall of the mouth of the coupling through hole 13, the hole wall of the mouth of the resonance hole 16 may also be chamfered or rounded.

In one embodiment, the mouth of the coupling through hole 13 having a smaller inner diameter is provided on the second surface 12, and the mouth of the coupling through hole 13 having a larger inner diameter is provided on the first surface 11.

In another embodiment, referring to fig. 3 and 4, the other way round is to arrange the mouth of the coupling through hole 13 with smaller inner diameter on the first surface 11 and the mouth of the coupling through hole 13 with larger inner diameter on the second surface 12.

In an embodiment, a method for adjusting a degree of balance of a dielectric filter, which uses the capacitive coupling structure of the dielectric filter according to any of the embodiments described above, includes the following steps:

referring to fig. 2, 10 to 20, the balance of the symmetrical zero point is adjusted by changing the distance H0 between the closed annular notch 14 and the end surface of the coupling through hole 13 with the larger aperture.

On one hand, the balance degree of the symmetric zero point can be adjusted by adjusting the arrangement position of the closed annular notch 14 on the hole wall of the tapered hole section 131, that is, by changing the distance H0 between the closed annular notch 14 and the end face of the coupling through hole 13 with the larger hole diameter at the end face with the larger hole diameter; on the other hand, since the coupling through-hole 13 includes the tapered hole section 131, compared with a through-hole having a hole wall perpendicular to the first surface 11, the hole wall of the tapered hole section 131 is inclined, which not only facilitates forming the metal layer 20 on the hole wall of the coupling through-hole 13, but also facilitates forming the closed annular gap 14 on the metal layer 20 of the tapered hole section 131 by using a cutting tool (including a cutter, a laser, etc.), thereby improving the production efficiency. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

Referring to fig. 11, fig. 11 is a graph of S-parameter of a capacitive coupling structure of a dielectric filter under a conventional 8-cavity double-zero-point symmetric structure, where the entire hole wall of a coupling through hole 13 of the dielectric filter under the conventional 8-cavity double-zero-point symmetric structure is perpendicular to the surface of a dielectric block 10, and as can be seen from fig. 11, the left and right symmetrical zero points are uneven, and if the balance degree of the symmetrical zero points needs to be adjusted, the adjustment needs to be performed by adjusting the design of the cavity arrangement structure.

Referring to fig. 12, fig. 12 is a capacitive coupling structure of a dielectric filter under the 8-cavity double-zero symmetric structure according to an embodiment, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter graph when H0 is 2mm, as can be seen from fig. 12, a difference between the left zero and the right zero is changed from the conventional 7.6dB to 19.6 dB.

Referring to fig. 13, fig. 13 is a capacitive coupling structure of a dielectric filter in an 8-cavity double-zero symmetric structure according to an embodiment, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter curve diagram when H0 is 1.55mm, and it can be seen from fig. 13 that a difference between the left and right zeros is smaller than a difference between the left and right zeros when H0 is 2mm, that is, the difference between the left and right zeros is further reduced.

Referring to fig. 14, fig. 14 is a capacitive coupling structure of a dielectric filter in an 8-cavity double-zero symmetric structure according to an embodiment, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter curve diagram when H0 is 1.5mm, and it can be seen from fig. 14 that a difference between the left zero and the right zero is smaller than a difference between the left zero and the right zero when H0 is 1.55mm, that is, the difference between the left zero and the right zero is further reduced.

Referring to fig. 15, fig. 15 is a capacitive coupling structure of a dielectric filter under the cavity double-zero symmetric structure according to an embodiment 8, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter curve diagram when H0 is 1.4mm, as can be seen from fig. 15, a difference value between the left zero point and the right zero point is smaller than a difference value between the left zero point and the right zero point when H0 is 1.5mm, that is, the difference value between the left zero point and the right zero point is further reduced.

Referring to fig. 16, fig. 16 is a capacitive coupling structure of a dielectric filter in an 8-cavity double-zero-point symmetric structure according to an embodiment, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter curve diagram when H0 is 1.35mm, as can be seen from fig. 16, a difference value between the left zero point and the right zero point is smaller than a difference value between the left zero point and the right zero point when H0 is 1.4mm, which is zero, that is, the difference value between the left zero point and the right zero point is further reduced to reach an equilibrium.

Referring to fig. 17, fig. 17 is a capacitive coupling structure of a dielectric filter in an 8-cavity double-zero-point symmetric structure according to an embodiment, the capacitive coupling structure of the dielectric filter can refer to fig. 2, fig. 6, and fig. 8 to fig. 10, and an S parameter curve diagram when H0 is 1.0mm, as can be seen from fig. 17, the left and right zero points are uneven, and exhibit an effect of being high on the left and low on the right, which is opposite to the effect of being high on the left and low on the right presented in fig. 11 to fig. 16.

That is, when H0 gradually decreases from a higher value to a value corresponding to a balance between the left and right zero points, for example, 1.35mm, the difference between the left and right zero points gradually decreases, and the effect of high left and low right is exhibited; when H0 further decreases from the left and right zero points when they are balanced with each other, corresponding to, for example, 1.35mm, the difference between the left and right zero points gradually increases, and the effect of being low on the left and high on the right is exhibited.

Referring to fig. 18, fig. 18 is a capacitive coupling structure of a dielectric filter under the 8-cavity double-zero symmetric structure according to an embodiment, where the capacitive coupling structure of the dielectric filter can refer to fig. 3, and an S-parameter curve diagram when H0 is 4.5mm, the capacitive coupling structure of the dielectric filter in fig. 3 is opposite to that in fig. 2, 6, 8, and 9 in the orientation of the tapered hole section 131 of the coupling through hole 13, and as can be seen from fig. 18, a difference between the left and right zeros is changed from a conventional 7.6dB (see fig. 10) to 10.2 dB. That is, when the tapered hole sections 131 of the coupling through-holes 13 are oriented in opposite directions, the balance of the left and right zero points of the product can be changed without changing the row cavities. Similarly, when the size of H0 is changed, the above balance adjustment effect is also obtained, and further, refer to fig. 19 and fig. 20.

Referring to fig. 19, fig. 19 is a capacitive coupling structure of a dielectric filter in a cavity double-zero symmetric structure according to an embodiment 8, the capacitive coupling structure of the dielectric filter can refer to fig. 3, and an S-parameter curve diagram when H0 is 4mm, it can be seen from fig. 19 that a difference between the left zero and the right zero is smaller than a difference between the left zero and the right zero when H0 is 4.5mm, and the two zeros exhibit an effect of high left and low right.

Referring to fig. 20, fig. 20 is a capacitive coupling structure of a dielectric filter in a cavity double-zero symmetric structure according to an embodiment 8, the capacitive coupling structure of the dielectric filter can refer to fig. 3, and an S-parameter curve diagram when H0 is 1.17mm, and it can be seen from fig. 20 that the left and right zeros exhibit a low-left effect and a high-left effect.

In one embodiment, please refer to fig. 10 again, a filter includes the capacitive coupling structure of the dielectric filter according to any one of the above embodiments. The filter is a dielectric filter having a double zero symmetric structure with 4 or more cavities, and may be, for example, a dielectric filter having a double zero symmetric structure with 4 cavities, a dielectric filter having a double zero symmetric structure with 5 cavities, a dielectric filter having a double zero symmetric structure with 6 cavities, a dielectric filter having a double zero symmetric structure with 7 cavities, or a dielectric filter having a double zero symmetric structure with 8 cavities.

On one hand, the balance degree of the symmetrical zero point can be correspondingly adjusted by adjusting the arrangement position of the closed annular notch 14 on the hole wall of the conical hole section 131, namely changing the distance H0 between the closed annular notch 14 and the end face of the coupling through hole 13 with the larger hole diameter at one end; on the other hand, since the coupling through-hole 13 includes the tapered hole section 131, compared with a through-hole having a hole wall perpendicular to the first surface 11, the hole wall of the tapered hole section 131 is inclined, which not only facilitates forming the metal layer 20 on the hole wall of the coupling through-hole 13, but also facilitates forming the closed annular gap 14 on the metal layer 20 of the tapered hole section 131 by using a cutting tool (including a cutter, a laser, etc.), thereby improving the production efficiency. Meanwhile, on the premise of not changing the row cavity, the balance degree of the left zero point and the right zero point of the product can be changed.

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, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.