CN113948839A

CN113948839A - Low-pass filter

Info

Publication number: CN113948839A
Application number: CN202111123348.6A
Authority: CN
Inventors: 刘海; 朱晖; 钟伟刚; 金锐; 刘�文
Original assignee: Wuhan Fangu Ceramic Material Co ltd
Current assignee: Wuhan Fangu Ceramic Material Co ltd
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2022-01-18
Anticipated expiration: 2041-09-24
Also published as: CN113948839B

Abstract

A low-pass filter can be suspended in a PCB and at least comprises a dielectric filter, a low-pass cover and a shielding cover, wherein a conducting layer is coated on the dielectric filter, the PCB is fixed on the dielectric filter, a groove is formed in the PCB, the low-pass suspension is installed right above the groove of the PCB, arranged in the dielectric filter and electrically connected with the PCB, and the shielding cover is arranged above the PCB and covered on the low-pass cover. The low-pass filter utilizes the multilayer structure of the PCB, changes the size of the low-pass branch node capacitance of the strip line by utilizing the area of the copper-clad layer between the PCBs, fully utilizes the characteristics of different media to reduce the volume of low-pass, reduces low-pass loss at the same time, and can improve fifty percent of signal loss in actual test.

Description

Low-pass filter

Technical Field

The invention relates to the technical field of communication, in particular to a low-pass filter.

Technical Field

The low pass is one of indispensable devices in a wireless communication system as a frequency-selective device, and the strip line low pass is widely applied in the field of 5G communication in particular.

At present, most of the existing low-pass filters installed on a PCB in the filter industry are formed by pressing two dielectric substrates, wherein only one side of one dielectric substrate is covered with a metal layer for grounding; after one surface of the other dielectric plate is covered with a metal layer, a circuit layer for forming a strip line low-pass circuit is etched, the other surface of the other dielectric plate is covered with a metal layer for grounding, and the last two dielectric plates are pressed in an involutive mode by taking the non-grounded surface as an involutive surface to form the strip line low-pass circuit.

In view of the above, it is necessary to design a low-pass filter to solve the above problem.

Disclosure of Invention

The invention aims to provide a low-pass filter to solve the problems that the low-pass loss is large and the electric index and the stability of the filter are influenced.

In order to achieve the purpose, the invention provides the following technical scheme: a low-pass filter can be installed on a PCB and comprises a dielectric filter, a low-pass filter and a shielding cover, wherein a conducting layer is coated on the dielectric filter, the PCB is fixed on the dielectric filter, a groove is formed in the PCB, a low-pass suspension is installed in the groove of the PCB, is arranged right above the dielectric filter and is electrically connected with the PCB, and the shielding cover is arranged above the PCB and covers the low-pass filter.

Preferably, the groove on the PCB board is a hollow groove, welding points are arranged on two sides of the groove, and the low-pass welding is performed on the welding points.

Preferably, the upper surface and the lower surface of the PCB are provided with copper layers, the upper surface and the lower surface of the PCB are provided with areas for stripping the copper layers, and the groove is arranged in the areas.

Preferably, the low pass comprises a strip line low pass and a medium block, wherein the strip line low pass comprises an assembling end, a low pass main body, a high resistance and a low resistance, the low resistance is integrally formed inside the medium block, and the medium block is made of polytetrafluoroethylene, plastic or ceramic and the like.

Preferably, the low pass is arranged in a groove of the PCB, and the dielectric block can support and position the low pass of the strip line.

Preferably, the groove on the PCB board is a blind groove, the blind groove comprises a bottom wall with a copper layer exposed, and welding points are arranged on two sides of the blind groove.

Preferably, the low pass comprises an assembling end, a low pass body and a high resistance, the assembling end is welded with the welding point to fix the low pass in the groove, and the low pass body part of the low pass is suspended above the groove.

Preferably, the upper surface and the lower surface of the PCB are provided with copper layers, the upper surface of the PCB is provided with a region for stripping the copper layer, the region is internally provided with another copper-clad layer, the copper-clad layer is defined as low resistance, and the low resistance is tightly connected with the low-pass high resistance.

Preferably, two insulating circular rings are arranged on the dielectric filter, a first PIN and a second PIN are placed in the insulating circular rings, and the positions of the second PINs correspond to the positions of the low-pass assembling ends.

Compared with the prior art, the low-pass filter has the advantages that the low-pass suspension is fixed on the PCB, the area of the copper clad layer between the PCBs is controlled by utilizing the multilayer structure of the PCB to change the capacitance of the low-pass branch section of the strip line, the low-pass volume is reduced by fully utilizing the air medium and the plate medium, the loss is reduced, and the loss of signals is improved by fifty percent in an actual test.

Drawings

FIG. 1 is a schematic structural diagram of a first low-pass filter according to the present invention;

FIG. 2 is a schematic structural diagram of a cross section of a first low-pass filter according to the present invention;

FIG. 3 is a schematic view of an integrally formed low-pass structure;

FIG. 4 is a schematic structural diagram of a second low-pass filter according to the present invention;

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, the dielectric filter 10 has a conductive layer 101, two insulating rings 30 are disposed on the conductive layer 101, the insulating rings 30 are sleeved outside the PIN i 20 and the PIN ii 21, so that the PIN i 20 and the PIN ii 21 are insulated from the conductive layer 101, wherein the position of the PIN ii 21 corresponds to the position of the mounting end 501 of the low pass 50. The PCB 40 with the multilayer structure is welded above the dielectric filter 10, copper layers are attached to the upper surface and the lower surface of the PCB 40, the upper surface of the PCB is provided with a rectangular area 41, the copper layers of the rectangular area 41 are dug out, a hollowed rectangular groove 411 is arranged in the rectangular area 41, welding points 412 are respectively arranged on two sides of the rectangular groove 411, a low-pass main body 502 of the low-pass 50 is partially suspended above the groove 411, an assembling end 501 of the low-pass 50 is welded on the welding points 412, a low resistance 413 is further arranged in the rectangular area 41, the low resistance 413 is welded with a high resistance 503 of the low-pass 50, so that the whole low-pass 50 is suspended and installed in the PCB 40, of course, the low resistance 413 can also be arranged at the bottom of the rectangular groove 411, and at the time, the high resistance 503 of the low-pass 50 needs to be welded with the low resistance 413 at the bottom of the rectangular groove 411 after being bent to a certain degree. The shield cover 60 is soldered over the rectangular area 41 of the PCB board 40 to completely cover it, thereby preventing external signal interference.

As shown in FIG. 2, a low resistance 413 is arranged in a rectangular area 41 of the upper surface of the PCB 40 from which a copper layer is stripped, the low resistance 413 is tightly attached to a low pass 50 above the low resistance 413, a rectangular groove 411 is arranged on the PCB below the low pass 50 in the rectangular area 41, the low pass body of the low pass 50 is suspended above the rectangular groove 411, and the size and the vertical distance of the rectangular groove 411 can be adjusted according to design.

As shown in fig. 3, the low pass 5 in the figure is composed of two parts, namely a strip line low pass 51 and a dielectric block 52, wherein the strip line low pass 51 further comprises an assembling end 511, a low pass main body 512, a high resistance 513 and a low resistance 514, the low resistance 514 is integrally formed inside the dielectric block 52, the dielectric block 52 can support and position the strip line low pass 51, and the material of the dielectric block is polytetrafluoroethylene, plastic or ceramic.

As shown in fig. 4, the dielectric filter 10 has a conductive layer 101, two insulating rings 30 are disposed on the conductive layer 101, the insulating rings 30 are sleeved outside the PIN i 20 and the PIN ii 21, so that the PIN i 20 and the PIN ii 21 are insulated from the conductive layer 101, wherein the position of the PIN ii 21 corresponds to the position of the mounting end 511 of the low pass 5. The PCB 40 with the multilayer structure is welded on the dielectric filter 10, copper layers are attached to the upper surface and the lower surface of the PCB 40, a rectangular area 41 is arranged on each of the upper surface and the lower surface of the PCB, the copper layer of the rectangular area 41 is excavated, a rectangular blind groove 411 is arranged in the rectangular area 41, a welding point 412 is respectively arranged on each of two sides of the rectangular blind groove 411, an assembling end 511 of the low pass 5 is welded on the welding point 412, the low pass 5 can be suspended and fixed in the rectangular blind groove 41, and the shielding cover 60 is welded above the rectangular area 41 of the PCB 40 and completely covers the rectangular area 41, so that external signal interference is prevented.

According to the invention, the low-pass suspension is positioned on the PCB by using a method of positioning the low-pass suspension on the PCB, the area of the copper coating layer between the PCBs is controlled by using the multilayer structure of the PCB to change the capacitance of the low-pass branch node of the strip line, the air medium and the plate medium are fully used to reduce the volume of the low-pass, the low-pass loss is optimized, and in the actual test, the loss of signals is improved by fifty percent.

The above examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention, which is intended to be covered by the claims and any design similar or equivalent to the scope of the invention.

Claims

1. A low pass filter mountable on a PCB board, comprising:

a dielectric filter on which a conductive layer is coated,

the dielectric filter is fixed with a PCB, the PCB is provided with a groove,

the low pass suspension is arranged in the groove of the PCB and is arranged right above the dielectric filter and is electrically connected with the PCB,

a shield cover disposed over the PCB board overlying the low pass.

2. A low-pass filter as claimed in claim 1, characterized in that: the groove on the PCB is a hollow groove, welding points are arranged on two sides of the groove, and the low-pass welding is performed on the welding points.

3. A low-pass filter as claimed in claim 2, characterized in that: copper layers are arranged on the upper surface and the lower surface of the PCB, areas for stripping the copper layers are arranged on the upper surface and the lower surface of the PCB, and the grooves are formed in the areas.

4. A low-pass filter as claimed in claim 3, characterized in that: the low pass is composed of a strip line low pass and a medium block, wherein the strip line low pass comprises an assembly end, a low pass main body, a high resistance and a low resistance, the low resistance is integrally formed in the medium block, and the medium block is made of polytetrafluoroethylene, plastics or ceramics and the like.

5. The low pass filter of claim 4, wherein: the low-pass is arranged in the groove of the PCB, and the dielectric block can support and position the low-pass of the strip line.

6. A low-pass filter as claimed in claim 1, characterized in that: the groove on the PCB is a blind groove which comprises a bottom wall with a copper layer exposed, and welding points are arranged on two sides of the blind groove.

7. The low pass filter of claim 6, wherein: the low pass comprises an assembling end, a low pass main body and a high resistance, the assembling end is welded with the welding point to fix the low pass in the groove, and the low pass main body of the low pass is suspended above the groove.

8. The low pass filter of claim 7, wherein: copper layers are arranged on the upper surface and the lower surface of the PCB, a copper layer stripping area is arranged on the upper surface of the PCB, another copper-clad layer is arranged in the copper layer stripping area, the copper-clad layer is defined as low resistance, and the low resistance is tightly connected with the low-pass high resistance.

9. The low pass filter of claim 8, wherein: the medium filter is provided with two insulating circular rings, a PIN needle I and a PIN needle II are placed in the insulating circular rings, and the PIN needle II corresponds to the assembly end of the low pass.