CN106159395B

CN106159395B - Cavity filter, duplexer and radio remote unit

Info

Publication number: CN106159395B
Application number: CN201510179758.0A
Authority: CN
Inventors: 童恩东
Original assignee: Shenzhen Tatfook Technology Co Ltd
Current assignee: Shenzhen Dafu Precision Technology Co.,Ltd.
Priority date: 2015-04-16
Filing date: 2015-04-16
Publication date: 2021-01-08
Anticipated expiration: 2035-04-16
Also published as: CN106159395A

Abstract

The invention provides a cavity filter which is good in temperature drift stability, free of power ignition and low in processing cost, and comprises a cavity and a cover plate, wherein the cover plate covers the cavity to form a resonant cavity, and the cover plate comprises a first cover plate close to one side of the cavity and a second cover plate far away from one side of the cavity; the first cover plate is provided with a resonance column which is integrally formed by punching and extends towards the bottom of the cavity, and the resonance column is in a cylindrical shape with one end close to the bottom of the cavity closed and one end far away from the bottom of the cavity opened; and a tuning screw rod is arranged on the second cover plate, extends into the resonance column and is abutted against the end face of the closed end of the resonance column.

Description

Cavity filter, duplexer and radio remote unit

Technical Field

The invention relates to the field of communication equipment, in particular to a cavity filter, a duplexer and radio frequency remote equipment.

Background

The cavity filter is used as a frequency selection device for selecting communication signal frequency and filtering out clutter or interference signals outside the communication signal frequency, and is widely applied to mobile base stations. The existing cavity filter generally comprises a cavity and a cover plate, wherein the cover plate covers the cavity to form a resonant cavity, a resonant column extending towards the cover plate is arranged at the bottom of the resonant cavity, and the resonant column is in a cylindrical shape with one closed end and one open end. And a tuning screw rod extending towards the interior of the resonant column is arranged on the cover plate so as to adjust the frequency of the cavity filter.

The existing resonant column mounting modes are two, and the first mode is as follows: punching a single cylindrical resonance column, processing an installation boss at the bottom of the cavity, and fixing the resonance column on the installation boss by using screws. This approach has several drawbacks: 1) for a cavity with a smaller volume, the space proportion occupied by the mounting boss is larger, so that the insertion loss of the cavity filter can be increased; 2) the contact surface of the resonance column and the mounting boss is uneven, so that poor contact between the resonance column and the mounting boss is caused, and intermodulation and insertion loss of the cavity filter are further influenced. 3) The resonant columns have certain assembly errors, so that the distance between the adjacent resonant columns and the flying rod cannot meet the preset requirement, and the coupling index between the resonant columns and the flying rod is further influenced.

The second way is: and (4) integrally punching and forming the resonant column and the cavity. Although this method overcomes the problems of the first solution, it has several disadvantages as follows: 1) The resonant column must be made of aluminum alloy material as the cavity, and the volume of the aluminum alloy is greatly influenced by the temperature change, so that the resonant column cannot be made in the mode for cavity filters with higher temperature drift requirements. 2) The tuning screw is positioned in the resonant cavity and is in capacitive coupling with the resonant column, and the threaded part on the outer surface of the tuning screw is relatively sharp, so that point discharge can be caused, and power ignition can be generated. 3) The cavity structure is complex, so the requirement on the stamping die is high.

Disclosure of Invention

The invention aims to provide a cavity filter, a duplexer and radio remote equipment which have the advantages of good temperature drift stability, no power ignition and low processing cost.

The cavity filter provided by the invention comprises a cavity and a cover plate, wherein the cover plate covers the cavity to form a resonant cavity, and the cover plate comprises a first cover plate close to one side of the cavity and a second cover plate far away from one side of the cavity; the first cover plate is provided with a resonance column which is integrally formed by punching and extends towards the bottom of the cavity, and the resonance column is in a cylindrical shape with one end close to the bottom of the cavity closed and one end far away from the bottom of the cavity opened; and a tuning screw rod is arranged on the second cover plate, extends into the resonance column and is abutted against the end face of the closed end of the resonance column.

The duplexer provided by the invention comprises a receiving filter and a transmitting filter, wherein the receiving filter is connected between a receiving terminal and an antenna terminal, the transmitting filter is connected between a transmitting terminal and the antenna terminal, and the receiving filter and the transmitting filter are the cavity filters provided by the invention.

The radio frequency remote equipment provided by the invention comprises a radio frequency transceiver module, a power amplifier module and the duplexer provided by the invention, wherein the radio frequency transceiver module is connected with the power amplifier module, and the power amplifier module is connected with the duplexer.

According to the cavity filter provided by the invention, the resonant column and the first cover plate are integrally formed, so that the resonant column can be made of a high-temperature floating stability material different from that of the cavity, and the temperature drift stability of the cavity filter is improved. The first cover plate is only a flat plate, the structure is much simpler compared with the cavity, and the corresponding die structure for punching the resonance column and the first cover plate is also very simple. In addition, the tuning screw assembly is positioned outside a resonant cavity formed by the cavity of the first cover plate cover, and no electromagnetic field exists around the tuning screw assembly, so that point discharge and power ignition cannot be generated.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a perspective view of a cavity filter;

FIG. 2 is a cross-sectional view of a cavity filter;

FIG. 3 is a perspective view of the first cover plate;

FIG. 4 is a perspective view of the second cover plate and tuning screw assembly;

fig. 5 is a schematic structural diagram of a duplexer;

fig. 6 is a schematic structural diagram of the radio remote device.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the 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.

Example one

As shown in fig. 1 to 4, the cavity filter provided in this embodiment includes a cavity 110 and a cover plate 120, the cover plate 120 covers the cavity to form a resonant cavity 130, and the cover plate 120 includes a first cover plate 121 on a side close to the cavity 110 and a second cover plate 122 on a side far from the cavity 110. The first cover plate 121 is provided with a resonant post 140 which is integrally formed by stamping and extends towards the bottom of the cavity 110. The resonant column 140 is a cylinder with one end close to the bottom of the cavity 110 closed and one end far away from the bottom of the cavity 110 opened. The second cover plate 122 is provided with a tuning screw 150, and the tuning screw 150 extends into the resonant column 140 and abuts against the end face of the closed end of the resonant column 140.

The tuning screw 150 is sleeved with a tuning nut 160 at an end away from the cavity 110, and a gasket 170 is disposed between the tuning nut 160 and the second cover plate 122.

When the tuning screw 150 is rotated in the forward direction, the tuning screw 150 moves towards the bottom of the cavity 110, and the end surface of the closed end of the resonant column 140 moves towards the bottom of the cavity 110 under the axial force of the tuning screw 150, so that the distance between the end surface of the closed end of the resonant column 140 and the bottom of the cavity 110 is reduced, and the capacitance between the resonant column and the bottom of the cavity is adjusted. And the tuning screw 150 is rotated reversely, the tuning screw 150 moves towards the cover plate 120, and the resonant column 140 is reset under the action of the elasticity of the resonant column 140, so that the distance between the end surface of the closed end of the resonant column 140 and the bottom of the cavity 110 is increased, and the capacitance between the resonant column and the bottom of the cavity is adjusted. When the tuning screw 150 is rotated to a predetermined position, the tuning screw 150 is sequentially sleeved with the washer 170 and the tuning nut 160, and the tuning nut 160 is rotated to lock the tuning screw 150 to the second cover plate 122.

The first cover plate 121 is stamped with ribs (not shown) connecting the adjacent resonant posts 140 to increase the coupling strength between the adjacent resonant posts 140. The side of the first cover plate 121 facing the cavity 110 is plated with a metal layer (not shown) as a good conductor of electromagnetic waves, such as a separate copper layer, or a copper layer plated with silver or tin.

The chamber 110 is made of an aluminum alloy having high strength and light weight. The first cover plate 121 and the resonant column 140 are made of a material whose volume is less subject to temperature change, such as 45 steel or rolled steel. The thickness of 45 steel or rolled steel is chosen to be both sufficiently elastic and strong.

The second cover plate 122 may be made of a metal material, such as an aluminum alloy. However, in view of the fact that the function of the cover plate for transmitting the electromagnetic wave is already achieved by the first cover plate 121, the second cover plate 122 may also be made of a non-metallic material, such as a PCB or plastic plate, from a cost perspective. Similarly, tuning screw 150 may be made of a metallic material as in the prior art. In the cavity filter in the prior art, the dielectric constant between the resonance column and the cover plate is changed by adjusting the depth of the tuning screw rod extending into the resonance column, so that the capacitance between the resonance column and the cover plate is changed, and the frequency of the cavity filter is further changed. The cavity filter of the embodiment changes the distance between the resonant column and the bottom of the cavity by adjusting the distance of the tuning screw penetrating into the resonant column so as to change the capacitance between the resonant column and the bottom of the cavity, and further change the frequency of the cavity filter. That is, the cavity filter of the present embodiment does not require a capacitive coupling between the tuning screw and the cavity or the resonant post, and therefore, from the viewpoint of cost, the tuning screw 150 of the present embodiment is preferably made of a non-metallic material, such as a plastic plate or a PCB plate.

Adopt the cavity filter that this embodiment provided, resonance post and first apron integrated into one piece, therefore the resonance post can adopt the high temperature stability material that wafts different with the cavity to make to can improve cavity filter's temperature drift stability. And the first cover plate is only a flat plate, the structure is much simpler compared with the cavity, and the corresponding die structure for punching the resonance column and the first cover plate is simpler. In addition, the tuning screw is positioned outside the resonant cavity formed by the cavity covered by the first cover plate, and no electromagnetic field exists around the tuning screw, so that point discharge and power ignition are avoided.

Example two

Fig. 5 is a schematic structural diagram of a duplexer of an embodiment of the present invention. As shown in fig. 5, the duplexer 50 includes a receiving filter 51 and a transmitting filter 52, the receiving filter 51 is connected between a receiving terminal 53 and an antenna terminal 54, and the transmitting filter 52 is connected between a transmitting terminal 55 and the antenna terminal 53, wherein the receiving filter 51 and the transmitting filter 52 are any cavity filter in fig. 1-4.

EXAMPLE III

Fig. 6 is a schematic structural diagram of a radio remote device according to an embodiment of the present invention. As shown in fig. 6, the remote radio device 60 includes a radio transceiver module 61, a power amplifier module 62, a power supply module 63, and the duplexer 60, where the radio transceiver module 61 is connected to the power amplifier module 62, and the power amplifier module 62 is connected to the duplexer 50. The power module 63 supplies power to the components of the remote rf device 60.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. The cavity filter is characterized by comprising a cavity and a cover plate, wherein the cover plate covers the cavity to form a resonant cavity, and the cover plate comprises a first cover plate close to one side of the cavity and a second cover plate far away from one side of the cavity;

the first cover plate is provided with a resonance column which is integrally formed by punching and extends towards the bottom of the cavity, and the resonance column is in a cylindrical shape with one end close to the bottom of the cavity closed and one end far away from the bottom of the cavity opened;

and a tuning screw rod is arranged on the second cover plate, the tuning screw rod extends into the resonance column and abuts against the end surface of the closed end of the resonance column, and the resonance column is made of a high-temperature floating stability material different from that of the cavity.

2. The cavity filter of claim 1, wherein ribs connecting adjacent resonator posts are stamped on the first cover plate.

3. The cavity filter according to claim 1, wherein a side of the first cover plate facing the cavity is plated with a metal layer as a good conductor of electromagnetic waves.

4. The cavity filter of claim 1, wherein the first cover plate and the resonant column are made of 45 steel or rolled steel.

5. The cavity filter of any one of claims 1 to 3, wherein the second cover plate is a non-metallic cover plate.

6. The cavity filter of any one of claims 1 to 3, wherein the tuning screw is a non-metallic tuning screw.

7. The cavity filter according to any one of claims 1 to 3, wherein the cavity is an aluminum alloy cavity.

8. The cavity filter according to any one of claims 1 to 3, wherein a tuning nut is sleeved on one end of the tuning screw, which is far away from the cavity, and a gasket is arranged between the tuning nut and the second cover plate.

9. A duplexer comprising a receive filter and a transmit filter, the receive filter being connected between a receive terminal and an antenna terminal, the transmit filter being connected between a transmit terminal and the antenna terminal, characterized in that the receive filter and the transmit filter are the cavity filter of any one of claims 1 to 8.

10. A radio remote unit, characterized by: comprising a radio frequency transceiver module, a power amplifier module and the duplexer of claim 9, wherein the radio frequency transceiver module is connected with the power amplifier module, and the power amplifier module is connected with the duplexer.