WO2021062923A1

WO2021062923A1 - Capacitive coupling structure and balance degree adjustment method of dielectric filter, and filter

Info

Publication number: WO2021062923A1
Application number: PCT/CN2019/118957
Authority: WO
Inventors: 谢懿非; 欧阳洲; 丁海; 林显添; 邸英杰
Original assignee: 京信通信技术(广州)有限公司
Priority date: 2019-09-30
Filing date: 2019-11-15
Publication date: 2021-04-08
Also published as: CN110600840B; CN110600840A

Abstract

The present application relates to a capacitive coupling structure and a balance degree adjustment method of a dielectric filter, and a filter. The capacitive coupling structure of a dielectric filter comprises a dielectric block and a metal layer. The dielectric block comprises a first surface and a second surface which are provided opposite to each other. The first surface is provided with a coupling through hole. By adjusting the arrangement position of a closed annular notch on the hole wall of a tapered hole section, i.e. changing the spacing H0 between the closed annular notch and an end surface of one end of the coupling through hole having a larger diameter, the balance degree of symmetrical zero points can be adjusted correspondingly; in addition, as the coupling through hole comprises the tapered hole section, with respect to a straight through hole of which the hole wall is perpendicular to a first surface, the hole wall of the tapered hole section is arranged obliquely, thus making it convenient to form the metal layer on the hole wall of the coupling through hole, and facilitating forming the closed annular notch on the metal layer of the tapered hole section by using a cutting tool (including a cutter, a laser, etc.), thereby improving the production efficiency.

Description

Capacitive coupling structure, balance adjustment method and filter of dielectric filter

Technical field

The present invention relates to the technical field of filters, in particular to a capacitive coupling structure, a balance adjustment method and a filter of a dielectric filter.

Background technique

The dielectric filter is a microwave filter that uses a dielectric resonant cavity to achieve frequency selection through multi-stage coupling. The surface of the dielectric filter is covered with a metal layer, and electromagnetic waves are confined in the dielectric body, forming a standing wave oscillation. Traditionally, the symmetrical zero point balance is adjusted by changing the cavity design of the dielectric filter. However, when redesigning the cavity structure, on the one hand, the workload of the cavity design is increased, and the design of the cavity is more difficult. On the other hand, after the cavity structure is changed, the performance indicators of the dielectric filter will be seriously affected. It can be seen that the adjustment of the symmetrical zero point balance of the capacitive coupling structure of the dielectric filter is quite difficult, which in turn leads to lower production efficiency, and ultimately greatly limits the application of the dielectric filter.

Summary of the invention

Based on this, it is necessary to overcome the shortcomings of the prior art and provide a capacitive coupling structure, a balance adjustment method and a filter of a dielectric filter, which can facilitate the adjustment of the balance of the symmetrical zero point and greatly improve the production efficiency.

The technical solution is as follows: a capacitive coupling structure of a dielectric filter, comprising: a dielectric block, the dielectric block includes a first surface and a second surface disposed oppositely, the first surface is provided with a coupling through hole, so The coupling through hole extends from the first surface to the second surface, the coupling through hole includes a tapered hole section with a gradually increasing inner diameter; a metal layer, which is laid on the outer wall of the dielectric block, And on the hole wall of the coupling through hole, the metal layer of the hole wall of the tapered hole section is provided with a closed annular gap.

The capacitive coupling structure of the dielectric filter described above, on the one hand, by adjusting the setting position of the closed annular notch on the hole wall of the tapered hole section, that is, changing the end face of the closed annular notch and the larger aperture of the coupling through hole When the distance between H0, the balance of the symmetrical zero point can be adjusted accordingly; on the other hand, since the coupling through hole includes a tapered hole section, compared to the through hole whose wall is perpendicular to the first surface, the tapered hole section The wall of the hole is inclined, so that it is convenient to form the metal layer on the wall of the coupling through hole, and it is convenient to use cutting tools (including cutters and lasers, etc.) to open a closed annular gap on the metal layer of the tapered hole section. , Which in turn can improve production efficiency. At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

In one of the embodiments, 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 the coupling through hole. The non-closed annular gap is provided.

In one of the embodiments, the non-closed annular gap includes a first end and a second end opposed to each other, the first end and the second end are spaced apart, and the first end is connected to the coupling through hole. The line connecting the axis of the first boundary line is the first boundary line, the line connecting the second end to the axis of the coupling through hole is the second boundary line, and the clamp between the first boundary line and the second boundary line The angle is β, and 0°<β<360°.

In one of the embodiments, there are more than two closed annular gaps, and the two or more closed annular gaps are spaced apart along the axial direction of the coupling through hole; the non-closed annular gaps are two Above, two or more non-closed annular gaps are arranged at intervals along the axial direction of the coupling through hole.

In one of the embodiments, the coupling through hole further includes a through hole section whose inner diameter remains unchanged, and the through hole section is communicated with the tapered hole section.

In one of the embodiments, there are two straight-through hole sections, one of the end of the straight-through hole section is connected with one end of the tapered hole section, and the end of the other through-hole section is connected with one end of the tapered hole section. The other end of the tapered hole section is butted and communicated.

In one of the embodiments, 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°.

In one of the embodiments, the first surface is further provided with two resonant holes spaced apart, the coupling through hole is located between the two resonant holes, and the metal layer is also laid on the resonant hole. On the wall of the hole.

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

The above-mentioned method for adjusting the balance of the dielectric filter, on the one hand, by adjusting the setting position of the closed annular notch on the hole wall of the tapered hole section, that is, changing the end face of the closed annular notch and the larger aperture of the coupling through hole When the distance between H0, the balance of the symmetrical zero point can be adjusted accordingly; on the other hand, since the coupling through hole includes a tapered hole section, compared to the through hole whose wall is perpendicular to the first surface, the tapered hole section The wall of the hole is inclined, so that it is convenient to form the metal layer on the wall of the coupling through hole, and it is convenient to use cutting tools (including cutters and lasers, etc.) to open a closed annular gap on the metal layer of the tapered hole section. , Which in turn can improve production efficiency. At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

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

The above-mentioned filter, on the one hand, by adjusting the setting position of the closed annular notch on the hole wall of the tapered hole section, that is, changing the distance H0 between the closed annular notch and the end face of the coupling through hole with the larger aperture. , The balance of the symmetrical zero point can be adjusted accordingly; on the other hand, since the coupling through hole includes a tapered hole section, the hole wall of the tapered hole section is inclinedly arranged relative to the through hole whose hole wall is perpendicular to the first surface. This not only facilitates the formation of the metal layer on the hole wall of the coupling through hole, but also facilitates the use of cutting tools (including cutters and lasers, etc.) to open a closed annular gap on the metal layer of the tapered hole section, thereby improving production efficiency . At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

Description of the drawings

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

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

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

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

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

Figure 6 is a cross-sectional view of an embodiment of Figure 5 at A-A;

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

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

Figure 9 is a cross-sectional view of another embodiment of Figure 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 an S parameter curve diagram of a capacitive coupling structure of a traditional dielectric filter;

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

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;

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

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;

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 1.0 mm in the capacitive coupling structure of the dielectric filter according to an embodiment of the present invention;

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

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

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

Reference signs:

10. Dielectric block; 11. First surface; 12. Second surface; 13. Coupling through hole; 131. Conical hole section; 132. Straight through hole section; 133, 45-degree inclined hole wall; 14. Closed annular gap 15. Non-closed annular gap; 151, the first boundary line; 152, the second boundary line; 16, the resonance hole; 20, the metal layer.

Detailed ways

In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, many specific details are explained in order to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "first" and "second" are only used for description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it may be directly connected to the other element or intervening elements may be present at the same time. In contrast, when an element is said to be "directly" connected to another element, there are no intervening elements.

In one embodiment, please refer to FIG. 1 and FIG. 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 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 a gradually increasing inner diameter. 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 the metal layer 20 of the hole wall of the tapered hole section 131 is provided with a closed annular gap 14.

The aforementioned capacitive coupling structure of the dielectric filter, on the one hand, by adjusting the position of the closed annular notch 14 on the wall of the tapered hole section 131, that is, the diameter of the closed annular notch 14 and the coupling through hole 13 are changed. When the distance H0 between the end faces of one end is large, the balance of the symmetrical zero point can be adjusted accordingly; on the other hand, because the coupling through hole 13 includes a tapered hole section 131, the through hole is perpendicular to the first surface 11 with respect to the hole wall In other words, the hole wall of the tapered hole section 131 is arranged obliquely, which not only facilitates the formation of the metal layer 20 on the hole wall of the coupling through hole 13, but also facilitates the use of cutting tools (including cutters and lasers, etc.) in the tapered hole section. The metal layer 20 of 131 is provided with a closed annular gap 14 so as to improve production efficiency. At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

It should be explained that the two ends of the closed annular gap 14 communicate with each other to form, for example, a closed circular ring, a closed square ring, or a closed elliptical ring. The non-closed annular gap 1514 is provided with opposite ends, and the opposite ends of the non-closed annular gap 1514 are spaced apart and are not connected to each other. That is, the non-closed annular gap 1514 is, for example, a non-closed circle. Ring, non-closed square ring or non-closed oval ring. In addition, the closed annular gap 14 and the non-closed annular gap 1514 are not laid with the metal layer 20 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 to the wall surface of the dielectric block 10 by removal or etching. Of course, the dielectric block 10 corresponds to the closed annular gap 14. The wall surface of the annular gap 1514 may not be electroplated or sprayed with the metal layer 20, so that the wall surface of the dielectric block 10 is exposed.

It should be noted that the dielectric block 10 is specifically, for example, a ceramic material dielectric block, and the metal layer 20 is specifically, for example, a silver layer or a copper layer, etc., which is not limited herein.

In an embodiment, please refer to FIG. 2 again, the metal layer 20 of the hole wall of the coupling through hole 13 is provided with a non-closed annular gap 1514. In this way, on the one hand, under the condition of ensuring that the capacitive coupling bandwidth of the dielectric filter reaches the preset value, since the metal layer 20 of the hole wall of the coupling through hole 13 is provided with a non-closed annular gap 1514, it can be used to a certain extent. Increase the width of the closed annular notch 14, for example, increase the width of the closed annular notch 14 from 0.1mm to 1mm or 2mm. Since the closed annular notch 14 with a width of 1mm or more can be easily processed by a tool, even in the cone A closed annular notch 14 is formed on the hole wall of the shaped hole section 131; on the other hand, a non-closed annular notch 1514 is provided on the metal layer 20 of the hole wall of the coupling through hole 13, and the non-closed annular notch 1514 can be used for 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, please refer to FIGS. 5-7, one of the first surface 11 and the second surface 12 is provided with a non-closed annular notch 1514 arranged around the coupling through hole 13 . In this way, the non-closed annular gap 1514 can also be formed on the first surface 11 or the second surface 12 and arranged around the coupling through hole 13, so that it is opposite to the non-closed annular gap 1514 formed on the hole wall of the coupling through hole 13. The closed annular gap 1514 is more convenient for production.

Further, referring to FIGS. 5 to 7, the non-closed annular gap 1514 includes a first end and a second end opposite to each other. The first end and the second end are spaced apart, a line connecting the first end to the axis of the coupling through hole 13 is a first boundary line 151, and the second end is to the coupling through hole 13 The line of the axis of is the second boundary line 152, and the 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 the first end to the second end, and the first end and the second end are spaced apart, so as to realize the non-closed annular gap 1514 around the coupling. Part of the hole 13 is arranged circumferentially instead of completely surrounding the circumference of the coupling through hole 13. At the same time, 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. When the β angle changes, the width and the narrowness of the capacitive coupling bandwidth change accordingly. β can be 45°, 90°, 135°, 180°, 225°, 250°, 300° or other such that the non-closed annular notch 1514 can cooperate with the closed annular notch 14 to adjust the capacitive coupling bandwidth angle.

As a modification of the above-mentioned embodiment, there are more than two closed annular notches 14, and more than two closed annular notches 14 are arranged at intervals along the axial direction of the coupling through hole 13.

As a modification of the above-mentioned embodiment, there are more than two non-closed annular gaps 1514, and more than two non-closed annular gaps 1514 are arranged at intervals along the axial direction of the coupling through hole 13.

Optionally, both the closed annular gap 14 and the non-closed annular gap 1514 may be one.

In an embodiment, referring to FIGS. 5, 8 and 9, the coupling through hole 13 further includes a through hole section 132 whose inner diameter remains unchanged, the through hole section 132 and the tapered hole section 131 Connected.

In one embodiment, there are two through hole sections 132, one of the through hole sections 132 has an end connected to one end of the tapered hole section 131, and the other through hole section 132 is connected to one end of the tapered hole section 131. The end is in butt and communicated with the other end of the tapered hole section 131.

As an optional solution, the tapered hole section 131 may be one tapered hole section 131, or two or more tapered hole sections 131 with different hole wall inclination are connected in sequence, or two or more tapered holes. The hole section 131 is formed by combining more than one through hole section, as long as the diameter of the tapered hole section 131 is satisfied to gradually increase from one end to the other end or show a trend of gradually increasing as a whole.

As an optional solution, there is one through hole section 132, and the through hole section 132 and the tapered hole section 131 communicate with each other and combine to form the coupling through hole 13.

As an optional solution, the coupling through hole 13 does not include a through hole section 132, and the coupling through hole 13 is a tapered hole section 131. In this way, it is not necessary to provide the coupling through hole 13 with a through hole section 132 directly on the dielectric block 10. It is enough to open and form a tapered hole, which is more convenient for manufacturing and processing.

In an embodiment, the angle between the hole wall of the tapered 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 tapered hole section 131 and the axis of the coupling through hole 13 is 45 degrees. In this way, on the one hand, it is convenient to lay the metal layer 20 formed on the hole wall of the coupling through hole 13, and on the other hand, it is also convenient to use cutting tools (including cutters and lasers) on the metal layer 20 on the hole wall of the coupling through hole 13. Etc.) A closed annular gap 14 and a non-closed annular gap 1514 are opened, thereby improving production efficiency.

As an optional solution, 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 is greater than 0° and less than 90° It is also possible within the range.

In one embodiment, the hole wall of the mouth of the coupling through hole 13 is chamfered or rounded. For details, referring to FIGS. 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 tapered hole section 131 and the axis of the coupling through hole 13, and at the same time, in order not to change the diameter of the mouth of the coupling through hole 13 as much as possible, it can be increased accordingly. The length H2 of the through hole section 132 adjacent to the smaller inner diameter of the tapered hole section 131 can increase the angle between the hole wall of the tapered hole section 131 and the axis of the coupling through hole 13 accordingly. .

In one embodiment, please refer to FIGS. 1 and 2 again, the first surface 11 is further provided with two spaced resonant holes 16, and the coupling through hole 13 is located between the two resonant holes 16. The metal layer 20 is also laid on the wall of the resonance hole 16.

Further, referring to FIGS. 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 resonant hole 16 can also be provided with a chamfered or rounded corner.

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

In another embodiment, referring to FIGS. 3 and 4, the reverse configuration is also possible, that is, the mouth with the smaller inner diameter of the coupling through hole 13 is arranged on the first surface 11, and the mouth with the larger inner diameter of the coupling through hole 13 is arranged on the first surface 11. Set on the second surface 12.

In one embodiment, a method for adjusting the balance of a dielectric filter adopts the capacitive coupling structure of the dielectric filter described in any of the above embodiments, and includes the following steps:

Please refer to FIGS. 2 and 10 to 20, by changing the distance H0 between the closed annular gap 14 and the end face of the coupling through hole 13 with a larger aperture, the balance of the symmetrical zero can be adjusted accordingly.

The above-mentioned method for adjusting the balance of the dielectric filter, on the one hand, by adjusting the position of the closed annular notch 14 on the hole wall of the tapered hole section 131, that is, the diameter of the closed annular notch 14 and the coupling through hole 13 are changed. When the distance H0 between the end faces of one end is large, the balance of the symmetrical zero point can be adjusted accordingly; on the other hand, because the coupling through hole 13 includes a tapered hole section 131, the through hole is perpendicular to the first surface 11 with respect to the hole wall In other words, the hole wall of the tapered hole section 131 is arranged obliquely, which not only facilitates the formation of the metal layer 20 on the hole wall of the coupling through hole 13, but also facilitates the use of cutting tools (including cutters and lasers, etc.) in the tapered hole section. The metal layer 20 of 131 is provided with a closed annular gap 14 so as to improve production efficiency. At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

Please refer to Figure 11. Figure 11 is the S-parameter curve of the capacitive coupling structure of the dielectric filter under the traditional 8-cavity double-zero symmetric structure, and the coupling through hole 13 of the dielectric filter under the traditional 8-cavity double-zero symmetric structure The whole wall of the hole is perpendicular to the surface of the dielectric block 10. It can be seen from Figure 11 that the two symmetrical zero points on the left and right are uneven. If the symmetrical zero point balance needs to be adjusted, it needs to be achieved by adjusting the cavity structure design.

Please refer to FIG. 12. FIG. 12 is a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve diagram when H0 is 2mm, as can be seen from Figure 12, the difference between the left and right zero points has changed from the traditional 7.6dB to 19.6dB.

Please refer to FIG. 13, which shows a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero point symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve diagram when H0 is 1.55mm. It can be seen from Figure 13 that the difference between the left and right zero points is smaller than the difference between the left and right zero points when H0 is 2mm, that is, the difference between the left and right zero points is further reduced. small.

Please refer to FIG. 14. FIG. 14 is a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve diagram when H0 is 1.5mm. It can be seen from Figure 14 that the difference between the left and right zero points is smaller than the difference between the left and right zero points when H0 is 1.55mm, that is, the difference between the left and right zero points is further Decrease.

Please refer to FIG. 15. FIG. 15 is a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve diagram when H0 is 1.4mm. It can be seen from Figure 15 that the difference between the left and right zero points is smaller than the difference between the left and right zero points when H0 is 1.5mm, that is, the difference between the left and right zero points is further Decrease.

Please refer to FIG. 16. FIG. 16 shows a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero point symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve diagram when H0 is 1.35mm. It can be seen from Figure 16 that the difference between the left and right zero points is less than that when H0 is 1.4mm. The difference between the left and right zero points is zero, that is, the difference between the left and right zero points. The value is further reduced to reach an equilibrium state.

Please refer to FIG. 17. FIG. 17 is a capacitive coupling structure of a dielectric filter under an 8-cavity double-zero symmetric structure. For the capacitive coupling structure of the dielectric filter, please refer to FIG. 2, FIG. 6, and FIG. 8 to FIG. 10. , S-parameter curve when H0 is 1.0mm. It can be seen from Figure 17 that the two zero points on the left and right are uneven, showing the effect of low left and high right, which is similar to the high left and low right shown in Figure 11 to Figure 16. The effect is opposite.

That is to say, when H0 gradually decreases from a higher value to the balance between the left and right zero points, for example, in the process of 1.35mm, the difference between the left and right zero points gradually decreases, and the effect is that the left is high and the right is low. ; When H0 is further reduced from the left and right zero points when the corresponding 1.35mm is further reduced, the difference between the left and right zero points gradually increases, and the effect of low left and high right is shown.

Please refer to Figure 18. Figure 18 shows the capacitive coupling structure of a dielectric filter with an 8-cavity double-zero point symmetric structure. The capacitive coupling structure of the dielectric filter can be seen in Figure 3. The S parameter when H0 is 4.5mm As shown in the graph, the capacitive coupling structure of the dielectric filter in FIG. 3 is in the opposite direction of the tapered hole section 131 of the coupling through hole 13 as compared with that in FIG. 2, FIG. 6, FIG. 8 and FIG. It can be seen that the difference between the left and right zero points has changed from the traditional 7.6dB (see Figure 10) to 10.2dB. In other words, when the direction of the tapered hole section 131 of the coupling through hole 13 is opposite, the balance of the left and right zero points of the product can also be changed without changing the discharge cavity. Similarly, when the size of H0 is changed, the effect of the above balance adjustment is also achieved. Please refer to FIG. 19 and FIG. 20 for further details.

Please refer to Figure 19, Figure 19 is a capacitive coupling structure of a dielectric filter with an 8-cavity double-zero point symmetric structure. Refer to Figure 3 for the capacitive coupling structure of the dielectric filter. S-parameter curve when H0 is 4mm In the figure, it can be seen from Figure 19 that the difference between the left and right zero points is smaller than the difference between the left and right zero points when H0 is 4.5mm, and the two zero points show the effect of high left and low right.

Please refer to Figure 20. Figure 20 is a capacitive coupling structure of a dielectric filter with an 8-cavity double-zero point symmetrical structure. Refer to Figure 3 for the capacitive coupling structure of the dielectric filter. S-parameters when H0 is 1.17mm The graph, as can be seen from Fig. 20, shows that the left and right zero points are low and high.

In one embodiment, please refer to FIG. 10 again, a filter including the capacitive coupling structure of the dielectric filter described in any one of the above embodiments. It should be noted that the filter is a dielectric filter with more than 4 cavities and a double-zero point symmetrical structure, for example, it can be a 4-cavity double-zero point symmetrical dielectric filter, a 5-cavity double-zero point symmetrical dielectric filter, and a 6-cavity double zero point symmetrical structure. Dielectric filter with symmetrical structure, 7-cavity double-zero symmetrical dielectric filter, or 8-cavity double-zero symmetrical dielectric filter.

The above-mentioned filter, on the one hand, by adjusting the setting position of the closed annular notch 14 on the hole wall of the tapered hole section 131, that is, changing the distance between the closed annular notch 14 and the end surface of the coupling through hole 13 with a larger aperture. When the distance H0, the balance of the symmetrical zero point can be adjusted accordingly; on the other hand, since the coupling through hole 13 includes a tapered hole section 131, compared to the through hole whose wall is perpendicular to the first surface 11, the tapered hole The hole wall of the section 131 is arranged obliquely, which not only facilitates the formation of the metal layer 20 on the hole wall of the coupling through hole 13, but also facilitates the use of cutting tools (including cutters and lasers, etc.) on the metal layer 20 of the tapered hole section 131 A closed annular gap 14 is opened, thereby improving production efficiency. At the same time, without changing the discharge cavity, the balance of the left and right zero points of the product can be changed.

The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the various technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, All should be considered as the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A capacitive coupling structure of a dielectric filter, which is characterized in that it comprises:

A dielectric block, the dielectric block includes a first surface and a second surface that are opposed to each other, the first surface is provided with a coupling through hole, and the coupling through hole extends from the first surface to the second surface, The coupling through hole includes a tapered hole section with a gradually increasing 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 the metal layer of the hole wall of the tapered hole section is provided with a closed annular gap.
The capacitive coupling structure of the dielectric filter according to claim 1, wherein 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 are among the A non-closed annular gap arranged around the coupling through hole is provided on at least one of the positions.
The capacitive coupling structure of a dielectric filter according to claim 2, wherein the non-closed annular gap includes a first end and a second end opposite to each other, and the first end and the second end are spaced apart from each other. It is provided that the line connecting the first end to the axis of the coupling through hole is a first boundary line, and the line connecting the second end to the axis of the coupling through hole is a second boundary line. The angle between the boundary line and the second boundary line is β, and 0°<β<360°.
The capacitive coupling structure of the dielectric filter according to claim 2, wherein there are more than two closed annular notches, and the two or more closed annular notches are along the axial direction of the coupling through hole. Are arranged at intervals; the number of the non-closed annular gaps is more than two, and the two or more non-closed annular gaps are arranged at intervals along the axial direction of the coupling through hole.
The capacitive coupling structure of a dielectric filter according to claim 1, wherein the coupling through hole further comprises a through hole section whose inner diameter remains unchanged, and the through hole section is connected to the tapered hole section through.
The capacitive coupling structure of a dielectric filter according to claim 5, wherein there are two through hole sections, and one end of the through hole section is butted with one end of the tapered hole section Connected, the end of the other straight-through hole section is connected to the other end of the tapered hole section.
The capacitive coupling structure of the 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°.
The capacitive coupling structure of a dielectric filter according to any one of claims 1 to 7, wherein two spaced resonant holes are further provided on the first surface, and the coupling through holes are located in the two resonant holes. Between the resonance holes, the metal layer is also laid on the hole wall of the resonance hole.
A method for adjusting the balance of a dielectric filter, which is characterized in that the capacitive coupling structure of the dielectric filter according to any one of claims 1 to 8 is adopted, and includes the following steps:

By changing the distance H0 between the closed annular gap and the end face of the coupling through hole with a larger aperture, the balance of the symmetrical zero point can be adjusted accordingly.
A filter, characterized by comprising the capacitive coupling structure of the dielectric filter according to any one of claims 1 to 8.