A capacitive coupling structure for dielectric filter

Abstract

The present invention provides a capacitive coupling structure for a dielectric filter. The dielectric filter comprises a ceramic dielectric block and a resonant cavity group. The resonant cavity group is arranged on the ceramic dielectric block. The present invention can realize both an adjacent cavity coupling structure and a non-adjacent cavity cross-coupling structure by selectively embedding a metal block for generating capacitive coupling inside the ceramic dielectric block and between any two adjacent resonant cavities, and by using a design of multiple resonant cavities, that is, realizing cross-coupling between cross-resonant cavities, thereby coupling between the resonant cavities on both sides of the metal block to generate a capacitive transmission zero point, thereby avoiding the problem of being unable to realize a transmission zero point with stronger coupling, and being stable and reliable as a whole.

Description

Technical Field

[0001] The invention belongs to the technical field of filters, and in particular relates to a capacitive coupling structure for a dielectric filter. Background Art

[0002] With the advent of the 5G era, filters need to be more miniaturized and integrated due to the requirements of Massive MIMO (massive antenna technology) for large-scale antenna integration. Under the condition of limited cavity size, metal coaxial cavity filters and metal cavity dielectric filters cannot achieve very high Q values ​​due to the loss of their own materials, resulting in limitations on various performance indicators.

[0003] In order to meet the miniaturization requirements of 5G base station filters, ceramic dielectric filters that are easier to miniaturize have become the mainstream solution. The electromagnetic wave resonance in the ceramic dielectric filter occurs inside the dielectric material. The traditional metal cavity is replaced by a metal coating, so the volume will be smaller and the weight will be lighter. In addition, the ceramic dielectric filter has the advantages of high Q value, good frequency selection characteristics, good operating frequency stability, low insertion loss, and low high and low temperature drift characteristics. However, the coupling structure of the existing ceramic dielectric filter is symmetrical in the left and right transmission zeros, which can only be adapted to filters with low out-of-band near-end suppression requirements and relatively symmetrical out-of-band suppression; moreover, due to structural limitations, the existing solution cannot achieve cross-coupling between cross-resonant cavities, resulting in the inability to achieve a stronger coupled transmission zero. Summary of the invention

[0004] In view of this, in order to solve the problems in the prior art, an object of the present invention is to provide a capacitive coupling structure for a dielectric filter.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a capacitive coupling structure for a dielectric filter, the dielectric filter includes a ceramic dielectric block and a resonant cavity group, the resonant cavity group is arranged on the ceramic dielectric block, the resonant cavity group includes a plurality of resonant cavities arranged in parallel and dispersedly arranged, grooves for adjusting the coupling amount of adjacent cavities are arranged between two adjacent single resonant cavities, and a metal block for generating capacitive coupling can be selectively embedded inside the ceramic dielectric block between any two adjacent resonant cavities.

[0006] Furthermore, at least one filter port may be selectively installed on the multiple resonant cavities.

[0007] Furthermore, the grooves include but are not limited to T-shaped grooves, cross-shaped grooves and straight-shaped grooves.

[0008] Compared with the prior art, the beneficial effect of the present invention is that a metal block for generating capacitive coupling can be selectively embedded between any two adjacent resonant cavities inside the ceramic dielectric block, and the design of multiple resonant cavities can realize both adjacent cavity coupling structure and non-adjacent cavity cross-coupling structure, that is, cross-coupling between cross-resonant cavities, so that a capacitive transmission zero point can be coupled between the resonant cavities on both sides of the metal block, avoiding the problem of being unable to achieve a transmission zero point with stronger coupling, and the overall stability and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of a capacitive coupling structure for a dielectric filter of the present invention;

[0010] Figure 2 yes Figure 1 Section view along AA direction;

[0011] Figure 3 yes Figure 1 Cross-sectional view along BB direction;

[0012] Figure 4 It is a schematic diagram of the structure of the present invention at another angle;

[0013] Figure 5 is a simulated frequency response curve after adding a metal block in an embodiment of the present invention;

[0014] Markings in the figure: 1, first resonant cavity, 2, second resonant cavity, 3, third resonant cavity, 4, fourth resonant cavity, 5, fifth resonant cavity, 6, sixth resonant cavity, 7, first port, 8, second port, 9, ceramic dielectric block, 10, metal block. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] A capacitive coupling structure for a dielectric filter, the dielectric filter comprises a ceramic dielectric block and a resonant cavity group, the resonant cavity group is arranged on the ceramic dielectric block, the resonant cavity group comprises a plurality of resonant cavities arranged in parallel and dispersedly, grooves for adjusting the coupling amount of adjacent cavities are arranged between two adjacent resonant cavities, and a metal block for generating capacitive coupling can be selectively embedded between any two adjacent resonant cavities inside the ceramic dielectric block.

[0017] Furthermore, at least one filter port may be selectively installed on the multiple resonant cavities.

[0018] Furthermore, the grooves include but are not limited to T-shaped grooves, cross-shaped grooves and straight-shaped grooves.

[0019] The present invention is described in detail below with reference to the accompanying drawings:

[0020] A capacitive coupling structure for a dielectric filter, such as Figure 4 As shown, the dielectric filter includes a ceramic dielectric block 9 and a resonant cavity group. The resonant cavity group is arranged on the ceramic dielectric block. The resonant cavity group includes a plurality of resonant cavities arranged in parallel and dispersedly arranged. The plurality of resonant cavities are sequentially: a first resonant cavity 1, a second resonant cavity 2, a third resonant cavity 3, a fourth resonant cavity 4, a fifth resonant cavity 5 and a sixth resonant cavity 6. The frequency is adjusted by adjusting the size and depth of the hole at the resonant cavity. At least one filter port can be selectively installed on the plurality of resonant cavities, such as Figure 2 As shown, in this embodiment, the filter port includes a first filter port 7 and a second filter port 8 .

[0021] like Figure 1 As shown, grooves (not marked in the figure) for adjusting the coupling amount between adjacent cavities are provided between the individual resonant cavities. The grooves include but are not limited to T-shaped grooves, cross-shaped grooves and straight grooves. The groove structure is flexible and changeable, which facilitates the adjustment of the coupling amount between adjacent cavities.

[0022] like Figure 3 As shown, a metal block 10 for generating capacitive coupling can be selectively embedded inside the ceramic dielectric block between any two adjacent resonant cavities. It should be noted here that the shape of the metal block 10 is not limited to a cylinder, and it can be any shape. Capacitive coupling is generated by changing the volume of the metal block 10 and the position inside the ceramic dielectric block 9, so that a capacitive transmission zero point can be coupled between the resonant cavities on both sides of the metal block 10, thereby avoiding the problem of being unable to achieve a stronger coupling transmission zero point, and the overall stability and reliability. In this embodiment, the metal block 10 is arranged between the third resonant cavity 3 and the fourth resonant cavity 4 to generate capacitive coupling, and then a capacitive transmission zero point is generated by coupling between the second resonant cavity 2 and the fifth resonant cavity 5. The present invention is simulated, and the simulation frequency response curve obtained after the simulation is as shown in FIG. Figure 5 As shown in the figure, there are two curves S11 and S21, curve S11 is the reflection characteristic curve, and curve S21 is the transmission characteristic curve. Figure 5 It can be seen that the capacitive coupling structure described in the present invention can generate corresponding capacitive transmission zero points, can avoid the problem of being unable to achieve a transmission zero point with stronger coupling, and is overall stable and reliable.

[0023] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A capacitive coupling structure for a dielectric filter, the dielectric filter comprising a ceramic dielectric block and a resonant cavity group, the resonant cavity group being arranged on the ceramic dielectric block, the resonant cavity group comprising a plurality of resonant cavities arranged in parallel and dispersedly, and grooves for adjusting the coupling amount of adjacent cavities being arranged between two adjacent resonant cavities, characterized in that: A metal block for generating capacitive coupling is embedded between any two adjacent resonant cavities in the ceramic dielectric block.

2. A capacitive coupling structure for a dielectric filter according to claim 1, characterized in that: At least one filter port may be selectively installed on the multiple resonant cavities.

3. A capacitive coupling structure for a dielectric filter according to claim 1, characterized in that: The grooves include but are not limited to T-shaped grooves, cross-shaped grooves and straight-shaped grooves.

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