CN113594651A

CN113594651A - Capacitive coupling structure of cavity filter and communication equipment

Info

Publication number: CN113594651A
Application number: CN202110760880.2A
Authority: CN
Inventors: 刘望; 钟志波
Original assignee: Anhui Tatfook Technology Co Ltd
Current assignee: Anhui Tatfook Technology Co Ltd
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2021-11-02

Abstract

The invention relates to a filter and communication equipment, which comprises a cavity, a cover plate for covering the cavity, at least two resonance tubes arranged in the cavity, a metal flying rod arranged between two adjacent resonance tubes, and a plastic screw rod, wherein the plastic screw rod penetrates through a through hole of the cover plate and is fastened with the cover plate through threads at the upper end of the plastic screw rod and a nut on the cover plate, the lower end of the plastic screw rod is fixed with the metal flying rod, and the distance between the metal flying rod and the adjacent resonance tubes is changed through the rotation of the plastic screw rod. Compared with the prior art, the invention can unify materials with capacitive cross coupling structure, reduce the types of fly rod prepared materials and overcome the difference of coupling amount caused by processing and assembling tolerance. Meanwhile, the yield is improved, the production and maintenance cost is reduced, and the production efficiency is improved.

Description

Capacitive coupling structure of cavity filter and communication equipment

Technical Field

The invention relates to the technical field of communication, in particular to a coaxial cavity filter technology.

Background

The filter is a frequency-selecting device, and is an essential component in communication equipment. The signal in a certain frequency band is subjected to minimum loss passing, and signals in other frequency bands are greatly inhibited, so that the function of selecting the signal in the required frequency band is achieved.

With the development of mobile communication, the filter is required more and more. Low cost and fast mass production debugging are becoming a demand in the filter production industry. The capacitive cross-coupling structure of the conventional coaxial cavity filter is shown in fig. 5, and includes resonator tubes 1, a metal flying rod 2, a plastic flying rod clamping seat 3, and the like, where the metal flying rod 2 is fixed on a cavity wall 5 between adjacent resonator tubes through the plastic flying rod clamping seat 3. By the plate capacitance principle, the metal flying rod 2 transfers the capacitive coupling between the two resonator tubes. The larger the coupling plate, the closer the distance to the resonator tube, and the greater the amount of capacitive coupling. Because the metal flying rod is fixed on the wall of the cavity body through the plastic clamping seat, the coupling amount of the metal flying rod cannot be adjusted, and one filter usually needs a plurality of metal flying rods with different coupling amounts, so that a plurality of flying rods with different sizes are needed. This structure has the following disadvantages:

1. the metal flying rod has various types of materials, the materials are not prepared, the waste is serious, a large amount of working hours are wasted when the flying rod is replaced during production and debugging, and the production efficiency is not high.

2. The metal flying rod is affected by machining and assembling tolerance, and the coupling amount can not meet the requirement required by the filter, so that the performance of the filter is reduced, and indexes cannot be optimized. And needs to be uncovered for maintenance, thereby increasing the production cost.

3. The flying rod clamping seat is fixed on the cavity through the cavity wall groove, the reliability of the flying rod depends on the tolerance of the cavity groove, the requirement on the tolerance of the cavity groove is high, and the processing difficulty and the processing cost are improved.

Disclosure of Invention

The invention aims to solve the technical problem of providing a capacitive coupling structure of a cavity filter and communication equipment, which have uniform flying bar materials, reduce processing difficulty and improve production efficiency, aiming at the defects in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the capacitive coupling structure of the cavity filter comprises a cavity, a cover plate covering the cavity, at least two resonance tubes arranged in the cavity, a metal flying rod arranged between every two adjacent resonance tubes, and a plastic screw rod, wherein the plastic screw rod penetrates through a through hole of the cover plate and is fastened with the cover plate through threads at the upper end of the plastic screw rod and nuts on the cover plate, the lower end of the plastic screw rod is fixed with the metal flying rod, and the distance between the metal flying rod and the adjacent resonance tubes is changed through the rotation of the plastic screw rod.

Further:

the metal flying rod and the plastic screw are formed into a whole.

The plastic screw is fastened with the cover plate through a nut.

The edge of the metal flying rod is a smooth chamfer.

The longitudinal section of the metal flying rod is groove-shaped, and the lower end of the plastic screw rod extends into the groove bottom of the metal flying rod and is fixed with the metal flying rod.

The metal flying rod is cylindrical, disc-shaped or sheet-shaped.

A communication device comprising a filter as described above.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the plastic screw rod is rotated, so that the coupling quantity of capacitive cross coupling between adjacent resonance tubes is changed, materials with capacitive cross coupling structures can be unified, the types of flying bar prepared materials are reduced, and the difference of the coupling quantity caused by processing and assembling tolerance is overcome. Meanwhile, the yield is improved, the production and maintenance cost is reduced, and the production efficiency is improved.

Drawings

FIG. 1 is a schematic cross-sectional view of an embodiment of a capacitive coupling structure of a cavity filter according to the present invention;

fig. 2 is a schematic top view of the capacitive coupling structure of the cavity filter according to the embodiment of the present invention, in which the rotation angle of the flying bar is 0, and the flying bar faces two adjacent resonator tubes;

fig. 3 is a schematic top view of a capacitive coupling structure of a cavity filter according to an embodiment of the present invention, in which the rotation angle of the flying rod is 15 degrees, and the flying rod is obliquely aligned to two adjacent resonator tubes;

fig. 4 is a schematic top view of the embodiment of the capacitive coupling structure of the cavity filter according to the present invention, in which the rotation angle of the flying rod is 30 degrees, and the flying rod is far away from two adjacent resonator tubes;

fig. 5 is a schematic cross-sectional view of a conventional capacitive cross-coupling structure.

Reference numerals: a cavity 10; a cover plate 20; a resonator tube 30; a metal fly rod 40; a plastic screw 50; the upper end 51 of the plastic screw; the lower end 52 of the plastic screw; a nut 60; and a coupling capacitor C.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

A capacitive coupling structure of a cavity filter is shown in fig. 1 and comprises a cavity 10, a cover plate 20 covering the cavity, at least two resonance tubes 30 arranged in the cavity, a metal flying rod 40 arranged between two adjacent resonance tubes 30 and a plastic screw rod 50. In this embodiment, the metal flying bar 40 traverses the cavity wall between adjacent resonator tubes. The upper end 51 of the plastic screw is provided with a thread, and the plastic screw passes through the through hole of the cover plate 20 and is fastened with the cover plate 20 through the thread at the upper end and the nut on the cover plate. The lower end 52 of the plastic screw 50 is fixed to the metal fly rod, and the metal fly rod 40 is rotated by the rotation of the plastic screw 50. The metal flying rod 40, the resonance tube 30 and the plastic screw 50 form a capacitive cross coupling structure of the filter, and the plastic screw is rotated to drive the metal flying rod 40 to rotate relative to the plastic screw 50, so that the size of the space between the resonance tube 30 and the metal flying rod 40 is changed, the size of the coupling capacitor is changed, and the adjustment of capacitive cross coupling is realized.

In some embodiments, the metal fly rod is integrally formed with the plastic screw. For example, injection molding, to form the two into one piece. In other embodiments, the metal flying bar can be fixed together with the plastic screw rod after being formed separately.

When the coupling amount is adjusted, the plastic screw rod is rotated to drive the metal flying rod to rotate, and the distances between two ends of the metal flying rod and the resonant tubes of the adjacent resonant tubes are changed respectively. In order to ensure the stability and reliability of the metal flying bar, when the plastic screw 50 is rotated to a proper position just to satisfy the required capacitive coupling amount, as shown in fig. 1, a rigid nut 60 is used to fasten the plastic screw 50 to the cover plate 20.

In some embodiments, the edge of the metal fly rod is rounded. The edges are in smooth chamfer transition, so that the metal flying rod is ensured to rotate, the electric field cannot suddenly change, and the risk of arc discharge is avoided.

As shown in fig. 1, in the present embodiment, the longitudinal section of the metal flying bar 40 is a groove shape, a groove bottom of the metal flying bar passes through a wall of the cavity between adjacent resonator tubes, and the groove walls at two ends of the metal flying bar form capacitive coupling with the adjacent resonator tubes respectively. In some embodiments, the recess opens toward the plastic screw 50, and the lower end 52 of the plastic screw 50 extends into the bottom of the metal fly rod 40 and is fixed thereto. In other embodiments, the metal fly rod may be cylindrical, disc-shaped, or sheet-shaped.

The metal fly rod can be made of metal such as iron, steel, aluminum or magnesium.

A communication device, such as a communication base station, comprises a cavity, an antenna, a PCB board and a capacitive coupling structure of the cavity filter, wherein the capacitive coupling structure comprises a plurality of resonance tubes, a metal flying rod penetrates through the cavity wall between the resonance tubes and is fixed at one end of a plastic screw rod, and the other end of the plastic screw rod is screwed with a cover plate screw hole. When the capacitive coupling quantity of the filter is adjusted, the plastic screw rod rotates relative to the cover plate, the metal flying rod rotates along with the plastic screw rod, the distance between the two ends of the metal flying rod and the adjacent resonance tubes is changed, and the adjustment of the capacitive coupling quantity between the adjacent resonance tubes is realized. The filter is arranged between the antenna and the PCB, and is used for passing signals in a required frequency band in a signal frequency band output by the antenna with minimum loss and inhibiting signals in other frequency bands to the maximum extent, so that the signals output by the antenna are selected and then are transmitted to the PCB.

When the capacitive coupling quantity needs to be adjusted, the plastic screw rod is rotated by means of the adjusting tool, the metal flying rod can be driven to rotate to different angles, the size of the space between the metal flying rod 40 and the resonance tube 30 is continuously changed, and meanwhile, the capacitance between the metal flying rod and the resonance tube is gradually and continuously changed, so that the purpose of changing the capacitive coupling quantity is achieved.

Specific rotation angles and capacitance changes can be seen in fig. 2 to 4. As shown in fig. 2, the metal flying bar 40 is relatively unrotated, that is, the rotation angle is 0, and at this time, both ends of the metal flying bar 40 respectively face one resonator tube 30, and at this time, the coupling capacitance C is maximum, and the coupling amount is maximum. As shown in fig. 3, the plastic screw 50 rotates to drive the metal flying rod 40 to rotate 15 degrees relative to fig. 2, and at this time, both ends of the metal flying rod 40 respectively slant to one resonator tube 30, and at this time, the coupling capacitance C decreases relative to the coupling capacitance in fig. 2. As shown in fig. 4, the metal flying bar 40 rotates 30 degrees with respect to fig. 2, and the two ends of the metal flying bar 40 are far away from the adjacent resonator tubes 30, and the coupling capacitance C is further reduced with respect to the coupling capacitance in fig. 3, and the coupling amount is almost zero. Fig. 2 to 4 are only an embodiment of the correspondence relationship between the rotation angle amplitude of the metal flying bar and the variation range of the coupling capacitance, and in other embodiments, the correspondence relationship between the rotation angle amplitude of the metal flying bar and the variation range of the coupling capacitance may be different from the embodiment shown in fig. 2 to 4. For example, the rotation angle amplitude of the metal flying rod corresponding to the change range of the coupling capacitance from the maximum to the minimum can be 60 degrees.

The metal flying rod is fixed on the plastic screw rod, and the plastic screw rod can be rotationally adjusted relative to the cover plate, so that the capacitance between the metal flying rod and the adjacent resonance tube is adjusted, and the plastic flying rod has the following effects: firstly, on the premise of not changing materials, the coupling quantity of the flying rod is changed, and the aim of adjusting the capacitive coupling quantity is achieved. Therefore, the universality of the metal flying rod is realized, the flying rods with different sizes are not required to be prepared, and the technical bottleneck problems of material consistency and material agreement in production are solved. Secondly, in the production debugging, need not spend a large amount of time to change the flying bar, improved production efficiency. Thirdly, the metal flying rod is affected by machining and assembling tolerance, the coupling amount is usually difficult to directly reach the required requirement, and under the condition, the existing filter can not be debugged to the optimal index, so that the performance of the filter is reduced. The metal flying rod rotates to different angles, the capacitance between the metal flying rod and the resonance tube can be gradually and continuously changed, the optimization state of indexes can be guaranteed, and the performance of the filter is improved. And fourthly, the metal flying rod is fixed on the plastic screw rod, and the plastic screw rod is fixed on the cover plate.

It should be understood that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some technical features; and such modifications and substitutions are intended to be included within the scope of the appended claims.

Claims

1. The utility model provides a capacitive coupling structure of cavity filter, includes resonant cavity, the apron that covers resonant cavity, sets up two at least resonance tubes in resonant cavity and sets up the metal flying rod between two adjacent resonance tubes which characterized in that: the plastic screw penetrates through the through hole of the cover plate and is fastened with the cover plate through threads at the upper end of the plastic screw and nuts on the cover plate, the lower end of the plastic screw is fixed with the metal flying rod, and the distance between the metal flying rod and the adjacent resonance tubes is changed through the rotation of the plastic screw.

2. The capacitive coupling structure of a cavity filter according to claim 1, wherein: the metal flying rod and the plastic screw are formed into a whole.

3. The capacitive coupling structure of a cavity filter according to claim 1, wherein: the plastic screw is fastened with the cover plate through a nut.

4. The capacitive coupling structure of a cavity filter according to claim 1, wherein: the edge of the metal flying rod is a smooth chamfer.

5. The capacitive coupling structure of a cavity filter according to claim 1, wherein: the longitudinal section of the metal flying rod is groove-shaped, and the lower end of the plastic screw rod extends into the groove bottom of the metal flying rod and is fixed with the metal flying rod.

6. The capacitive coupling structure of a cavity filter according to claim 1, wherein: the metal flying rod is cylindrical, disc-shaped or sheet-shaped.

7. A communication device comprising the capacitive coupling structure of the cavity filter of any of claims 1 to 6.