A structure for improving the performance of TEM all-dielectric filter

Abstract

The invention discloses a structure for improving the performance of a TEM all-dielectric filter, which comprises a dielectric cavity block, a signal shielding metal sheet and a PCB substrate, wherein the dielectric cavity block is welded to the PCB substrate, one end of the signal shielding metal sheet is welded to the dielectric cavity block and the other end is welded to the PCB substrate, a resonance hole is arranged on the dielectric cavity block, and a silver layer is plated on the inner wall of the resonance hole, and the depth of the silver layer is less than 2 / 3 of the depth of the resonance hole. The invention has a simple structure and is convenient to manufacture. By plating a silver layer of a certain depth in the resonance hole of the existing TEM all-dielectric filter, and controlling the height of the silver layer according to the shape, cavity material and size of the hole and the aperture of the resonance hole, the Q value of the filter is effectively improved while meeting the frequency requirements of the TEM all-dielectric filter. By controlling the ratio of the height of the silver layer to the height of the resonance hole, the Q value of the TEM all-dielectric filter using the invention is improved by at least 20% compared with the traditional TEM filter.

Description

Technical Field

[0001] The patent of this invention relates to base station filters, antenna tower amplifiers, combiners and anti-interference filters in the communication field, and specifically to a structure for improving the performance of a hybrid TEM all-dielectric filter. Background Art

[0002] With the rapid development of wireless mobile communications, the signal coverage range of low-frequency bands is larger, and the diffraction performance of signals is also better. The requirements for miniaturization of communication equipment at low frequencies are increasing, especially in the field of low-frequency filters. Transverse Electromagnetic (TEM) mode dielectric filters are common radio frequency devices and are used in wireless microphones, terminals and network equipment printed circuit boards (PCBs). The TEM mode dielectric filter in the prior art includes a ceramic dielectric body, and a conductive sintered silver paste forms a silver-plated layer on the surface of the ceramic dielectric body, wherein the ceramic dielectric body serves as a dielectric resonant cavity, and the silver-plated layer forms a metal cavity. The traditional TEM mode filter has not deeply studied the relationship between the cavity size, the resonant hole, the silver height and the Q value. The maximum Q value of different resonant apertures and silver heights under the same volume and the same dielectric material at the same frequency is even more than 1000 different, so it is urgent to find a Q value improvement structure with different silver heights and different apertures under the same volume, the same dielectric material and the same frequency. Summary of the invention

[0003] In view of the defects of the above-mentioned prior art, the purpose of the present invention is to solve the shortcomings of the above-mentioned background technology and provide a method for improving the Q value of the existing TEM mode dielectric filter. The method is composed of a dielectric cavity block, a resonant hole on the dielectric cavity block, a silver layer on the resonant hole, a signal shielding metal sheet, and a PCB connected to the dielectric block. Since the filter frequency is mainly affected by factors such as cavity size, dielectric material, resonant aperture, and silver height on the resonant hole, but these factors are closely related to the Q value of the filter, how these influencing factors can meet the frequency requirements and maximize the Q value is the key to the patent of the present invention.

[0004] In order to solve the above technical problems, the present invention adopts a cavity hybrid dielectric resonant structure for a filter, which includes a dielectric cavity block, a signal shielding metal sheet and a PCB substrate, the dielectric cavity block is welded to the PCB substrate, one end of the signal shielding metal sheet is welded to the dielectric cavity block, and the other end is welded to the PCB substrate, the dielectric cavity block is provided with a resonance hole, the inner wall of the resonance hole is plated with a silver layer, and the depth of the silver layer is less than 2 / 3 of the depth of the resonance hole.

[0005] In a preferred embodiment of the present invention, when the resonance hole is a circular hole and the dielectric constant of the dielectric cavity block is 6.8-80 and the ratio of the aperture of the resonance hole to the single cavity side length of the dielectric cavity block is 0.1-0.3, the ratio of the depth of the silver layer to the depth of the resonance hole is 0.2-0.8.

[0006] In a preferred embodiment of the present invention, when the resonance hole is a circular hole and the dielectric constant of the dielectric cavity block is 6.8-80 and the ratio of the aperture of the resonance hole to the single cavity side length of the dielectric cavity block is 0.1-0.45, the ratio of the depth of the silver layer to the depth of the resonance hole is 0.3-0.8.

[0007] In a preferred embodiment of the present invention, when the resonance hole is a square hole and the dielectric constant of the dielectric cavity block is 6.8-80 and the ratio of the side length of the resonance hole to the single cavity side length of the dielectric cavity block is 0.1-0.3, the ratio of the depth of the silver layer to the depth of the resonance hole is 0.2-0.8.

[0008] In a preferred embodiment of the present invention, when the resonance hole is a square hole and the dielectric constant of the dielectric cavity block is 6.8-80 and the ratio of the side length of the resonance hole to the single cavity side length of the dielectric cavity block is 0.1-0.45, the ratio of the depth of the silver layer to the depth of the resonance hole is 0.3-0.8.

[0009] In a preferred embodiment of the present invention, the dielectric cavity block is square or rectangular, a circuit is provided on one end face of the dielectric cavity block welded to the signal shielding metal sheet, and the remaining end faces of the dielectric cavity block are plated with a silver layer.

[0010] In a preferred embodiment of the present invention, the dielectric cavity block is formed of a whole block of dielectric material, and a plurality of the resonance holes are arranged at intervals on the dielectric cavity block.

[0011] In a preferred embodiment of the present invention, the dielectric cavity block is formed by splicing a plurality of resonance monoblocks, and the resonance hole is provided on the resonance monoblock.

[0012] In a preferred embodiment of the present invention, the signal shielding metal sheet is L-shaped.

[0013] The beneficial effects of the present invention are as follows: the present invention has a simple structure and is easy to manufacture. By plating a silver layer of a certain depth in the resonance hole of the existing TEM all-dielectric filter and controlling the height of the silver layer according to the shape, cavity material and size of the hole and the aperture of the resonance hole, the Q value of the filter is effectively improved while meeting the frequency requirements of the TEM all-dielectric filter. By controlling the ratio of the height of the silver layer and the height of the resonance hole, the Q value of the TEM all-dielectric filter using the present invention is improved by at least 20% compared with the traditional TEM filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0015] Figure 2 It is an exploded view of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0016] Figure 3 This is a front view of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0017] Figure 4 It is a side view of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0018] Figure 5 is a top view of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0019] Figure 6 is an AA cross-sectional view of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention;

[0020] Figure 7 This is a schematic diagram of a dielectric cavity block structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention; (square cavity with circular resonant hole)

[0021] Figure 8 This is a cross-sectional view of a dielectric cavity block BB of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention; (square cavity with square resonant hole)

[0022] Fig. 9 This is a schematic diagram of a dielectric cavity block of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention; (square cavity with square resonant hole)

[0023] Fig.10 This is a cross-sectional view of a dielectric cavity block CC of a structure for improving the performance of a TEM all-dielectric filter according to an embodiment of the present invention; (square cavity with circular resonant hole)

[0024] In the figure: 1- dielectric cavity block, 2- signal shielding metal sheet, 3- PCB substrate, 4- resonant hole, 5- silver layer. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] It can be seen from the structural schematic diagram of a TEM all-dielectric filter for improving the performance of the filter as shown in the accompanying drawings of the specification of the present invention that the present invention includes a dielectric cavity block 1, a signal shielding metal sheet 2 and a PCB substrate 3. The dielectric cavity block 1 can be a dielectric material with different dielectric constants. The dielectric cavity block 1 is welded to the PCB substrate 3. One end of the signal shielding metal sheet 2 is welded to the dielectric cavity block 1 (to prevent signal crosstalk and leakage), and the other end is welded to the PCB substrate 3. The radio frequency signal is connected to one end of the PCB substrate lead through the input and output port of the dielectric block. The other end of the PCB substrate can be connected to the radio frequency connector, or it can be soldered to the radio frequency motherboard through the overall patch of the PCB substrate to connect with the LNA and PA. A resonance hole 4 is provided on the dielectric cavity block 1, which is characterized in that: a silver layer 5 is plated on the inner wall of the resonance hole 4, and the depth of the silver layer 5 is less than 2 / 3 of the depth of the resonance hole 4.

[0027] When the required frequency and dielectric block material and volume are met, when the dielectric constant is between 6.8-80, the ratio of the resonant aperture d to the single cavity side length D of the dielectric cavity is between 0.1-0.3, that is, d / D=0.1-0.3; when the ratio of the upper silver height h of the resonant circular hole to the resonant hole height H is between 0.2-0.8, the Q value is optimal; when the dielectric constant is 6.8-80, the ratio of the resonant aperture d to the single cavity side length D of the dielectric cavity is between 0.1-0.45, that is, d / D=0.1-0.45; when the ratio of the upper silver height h of the resonant circular hole to the resonant hole height H is between 0.3-0.8, the Q value is more than 20% higher than that of the traditional TEM filter.

[0028] When the resonant rod is square and the dielectric constant is between 6.8-80, the ratio of the side length d1 of the resonant hole to the side length D of the single cavity of the dielectric cavity is between 0.1-0.3, that is, d1 / D=0.1-0.3; when the ratio of the upper silver height h of the resonant circular hole to the height H of the resonant hole is between 0.2-0.8, the Q value is optimal; when the dielectric constant is 6.8-80, the ratio of the side length d1 of the resonant hole to the side length D of the single cavity of the dielectric cavity is between 0.1-0.45, that is, d1 / D=0.1-0.45; when the ratio of the upper silver height h of the resonant circular hole to the height H of the resonant hole is between 0.3-0.8, the Q value is more than 20% higher than that of the traditional TEM filter.

[0029] It should be understood that the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a technician familiar with the field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A structure for improving the performance of a TEM all-dielectric filter, comprising a dielectric cavity block (1), a signal shielding metal sheet (2) and a PCB substrate (3), wherein the dielectric cavity block (1) is welded to the PCB substrate (3), one end of the signal shielding metal sheet (2) is welded to the dielectric cavity block (1) and the other end is welded to the PCB substrate (3), and a resonant hole (4) is provided on the dielectric cavity block (1), characterized in that: The inner wall of the resonance hole (4) is plated with a silver layer (5), and the depth of the silver layer (5) is less than 2 / 3 of the depth of the resonance hole (4).

2. The structure for improving the performance of the TEM all-dielectric filter according to claim 1, characterized in that: When the resonance hole (4) is a circular hole and the dielectric constant of the dielectric cavity block (1) is 6.8-80 and the ratio of the aperture of the resonance hole (4) to the side length of a single cavity of the dielectric cavity block (1) is 0.1-0.3, the ratio of the depth of the silver layer (5) to the depth of the resonance hole (4) is 0.2-2 / 3.

3. The structure for improving the performance of the TEM all-dielectric filter according to claim 1, characterized in that: When the resonance hole (4) is a circular hole and the dielectric constant of the dielectric cavity block (1) is 6.8-80 and the ratio of the aperture of the resonance hole (4) to the side length of a single cavity of the dielectric cavity block (1) is 0.1-0.45, the ratio of the depth of the silver layer (5) to the depth of the resonance hole (4) is 0.3-2 / 3.

4. The structure for improving the performance of the TEM all-dielectric filter according to claim 1, characterized in that: When the resonance hole (4) is a square hole and the dielectric constant of the dielectric cavity block (1) is 6.8-80 and the ratio of the side length of the resonance hole (4) to the side length of a single cavity of the dielectric cavity block (1) is 0.1-0.3, the ratio of the depth of the silver layer (5) to the depth of the resonance hole (4) is 0.2-2 / 3.

5. The structure for improving the performance of TEM all-dielectric filter according to claim 1, characterized in that: When the resonance hole (4) is a square hole and the dielectric constant of the dielectric cavity block (1) is 6.8-80 and the ratio of the side length of the resonance hole (4) to the side length of a single cavity of the dielectric cavity block (1) is 0.1-0.45, the ratio of the depth of the silver layer (5) to the depth of the resonance hole (4) is 0.3-2 / 3.

6. The structure for improving the performance of TEM all-dielectric filter according to claim 1, characterized in that: The dielectric cavity block (1) is rectangular, a circuit is provided on one end surface of the dielectric cavity block (1) welded to the signal shielding metal sheet (2), and the remaining end surfaces of the dielectric cavity block (1) are plated with a silver layer.

7. The structure for improving the performance of TEM all-dielectric filter according to claim 1, characterized in that: The dielectric cavity block (1) is formed from a whole block of dielectric material, and a plurality of the resonance holes (4) are arranged at intervals on the dielectric cavity block (1).

8. The structure for improving the performance of TEM all-dielectric filter according to claim 1, characterized in that: The dielectric cavity block (1) is formed by splicing a plurality of resonance monoblocks, and the resonance hole (4) is provided on the resonance monoblock.

9. The structure for improving the performance of TEM all-dielectric filter according to claim 1, characterized in that: The signal shielding metal sheet (2) is L-shaped.

Images