CN112635940B

CN112635940B - Cavity-in-line symmetrical capacitor device of cavity filter

Info

Publication number: CN112635940B
Application number: CN202011525921.1A
Authority: CN
Inventors: 夏文兵; 徐元洲; 杨世天; 柏友国; 彭贤志; 杨亚萍; 姜树海; 姚昌艳; 黄华
Original assignee: Huafeng Communication Technology Co ltd
Current assignee: Huafeng Communication Technology Co ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-06-14
Anticipated expiration: 2040-12-22
Also published as: CN112635940A

Abstract

The invention discloses a cavity filter in-line cavity type symmetrical capacitor device, which comprises: cavity and the harmonic oscillator that is in line structure that is located the cavity, be equipped with the bar electric capacity piece along cavity length direction parallel extension in the cavity, the bar electric capacity piece includes first end and second end, first end is passed through screw fixed connection and is kept away the blank structurally at first fixed electric capacity device, first fixed electric capacity device keeps away blank structure and cavity inner wall fixed connection, the first end is close to the input harmonic oscillator, the second end keeps away blank structure and cavity inner wall fixed connection through the fixed electric capacity device of second, the second end is 3.5mm to the interval of apron, the second end is 3.2mm to the distance of resonance post. The invention has the advantages that a zero point is respectively generated at the left side and the right side of the passband by adopting a cavity-walking mode in a straight-line mode under the condition that the U-shaped cavity-walking mode cannot be adopted due to space limitation, and stray signals at the left side and the right side of the passband are effectively inhibited.

Description

Cavity-in-line symmetrical capacitor device of cavity filter

Technical Field

The invention relates to a cavity filter, in particular to a capacitance symmetric cavity filter.

Background

In 2020, 5G communication technology has been used increasingly frequently in various fields; have no longer been just conceptual guesses and stayed in mind before; the method is also applied to the actual life of people, and the user has higher requirements on the appearance size and the index of the current machine type; the 5G is high and sensitive in actual frequency; the transmission speed and the output reading signal of the whole system meet the requirement of 5G frequency; the traditional symmetrical capacitor device in the prior art has limitations in cavity arrangement, a U-shaped cavity-walking form is usually adopted, if size space limitation is met, the conventional symmetrical capacitor device cannot be realized, and the product does not adopt a straight-line cavity to realize a suppression function because of an index parameter limitation structure, and a U-shaped structure and a cross-level zero point are required to meet technical parameters of customers; the increase of the overall dimension of the product is shown in figure 1; the Auto CAD software is designed into a traditional IQ structure, a passband oscillogram is realized through a fourth port 4 according to a first port 1, a second port 2 and a third port 3, and symmetrical capacitors 5 can be added on the left side and the right side of a passband in the oscillogram through a 'U-shaped structure design' point to realize symmetrical restraining strength adjustment of the left side and the right side; the U-shaped zero point structure is realized by spanning two stages, so the normal sizes are a first size 6 and a second size 7; the design can not meet the design requirement of the existing 5G straight-line cavity structure at all in terms of external dimension, and is not suitable in terms of cost and parameter indexes.

For example, chinese utility model patent publication No. CN209963200U discloses a 400MHz filter, which includes a cavity, wherein one side of the cavity is provided with an SMA connector I and the other side is provided with an SMA connector II, the top of the cavity is provided with a cover plate, the cover plate is connected with the side wall of the cavity through a plurality of screws and threaded rods, 4 corners of the cavity are provided with mounting holes, 6 resonance columns are arranged in the cavity side by side, and a coupling step is arranged between adjacent resonance columns, wherein a tap is arranged between the resonance columns at both ends and the SMA connector I, SMA II; the cavity is internally provided with the flying rod which is fixed on the inner wall of the cavity through a medium, but the structure still cannot meet the requirement that one zero point is generated on the left and the right of the passband.

Disclosure of Invention

The invention aims to solve the technical problem that the existing filter needs to enlarge the size of the filter in order to meet the requirement that the left side and the right side of a passband respectively have a zero point, and provides a cavity filter in-line cavity symmetrical capacitor device which adopts an in-line cavity-running mode to generate a zero point on the left side and the right side of the passband and effectively inhibits stray signals on the left side and the right side of the passband.

The zero point scheme is needed to be simulated to obtain the desired zero point, but not randomly obtained, and the zero point which is desired by us is achieved by adjusting the size of the part and the distance between the part and the resonant column in the simulation process, which is an innovative point of the invention.

The technical scheme of the invention is as follows: a cavity filter in-line cavity type symmetrical capacitor device comprises: cavity and the harmonic oscillator that is the straight line structure that is located the cavity, be equipped with the bar electric capacity piece along cavity length direction parallel extension in the cavity, the bar electric capacity piece includes low side and high-end, the low side passes through screw fixed connection on first fixed capacitor device keeps away the hollow structure, first fixed capacitor device keeps away hollow structure and cavity diapire fixed connection, the low side is close to the input harmonic oscillator, high-end keeps away hollow structure and cavity inside wall fixed connection through the second fixed capacitor device, the interval of high-end to apron is 3.5mm, the distance of high-end to the resonance post is 3.2 mm.

In the scheme, the strip-shaped capacitor piece is a brass piece.

The improvement of the scheme is that one side of the high end, which faces the harmonic oscillator, is coated with a polytetrafluoroethylene support.

In the above scheme, the first fixed capacitor device clearance structure includes a proximal end and a distal end, the proximal end is connected to the lower end through a screw, and the distal end is connected to the sidewall of the cavity.

The further improvement of the scheme is that the bottom of the near end is fixedly connected to the bottom of the cavity through a polytetrafluoroethylene fixing seat.

In the above scheme, the second fixed capacitor device clearance structure is an L-shaped connecting piece, and the horizontal part of the L-shaped connecting piece is fixedly connected to the top of the side wall of the cavity.

The invention has the advantages that under the condition that the U-shaped cavity-walking mode cannot be adopted due to space limitation, the cavity-walking mode in the straight-line form is adopted to respectively generate a zero point at the left side and the right side of the passband, and stray signals at the left side and the right side of the passband are effectively inhibited. The effect the same as that of the U-shaped structure is achieved, the feasibility of product parameters is improved, and the cost is reduced.

Drawings

FIG. 1 is a schematic diagram of a prior art filter structure;

FIG. 2 is a schematic diagram of the filter structure of the present invention;

FIG. 3 is a schematic view of a portion of the structure of FIG. 2;

FIG. 4 is a cross-sectional view of FIG. 2;

FIG. 5 is a graph of the filter frequency response of the present invention;

in the figure, 1, a first port, 2, a second port, 3, a third port, 4, a fourth port, 5, a symmetric capacitor, 6, a first size, 7, a second size, 8, a cavity, 9, a harmonic oscillator, 10, a strip-shaped capacitor plate, 11, a screw, 12, a polytetrafluoroethylene supporting body, 13, a polytetrafluoroethylene fixing seat, 14, a first fixed capacitor device clearance structure, 15, a second fixed capacitor device clearance structure, 16, a tap plate, 17, a third size, 18, and a fourth size.

Detailed Description

The technical scheme in the embodiment of the invention is clearly and completely described below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. Based on the embodiments of the present invention, all other embodiments without creative efforts of those skilled in the art are within the protection scope of the present invention.

As shown in fig. 2-4, a symmetrical capacitor device with cavity filter in-line cavity comprises: cavity 8 with be located the harmonic oscillator 9 that is in line structure in the cavity, be equipped with in the cavity along cavity length direction parallel extension's bar electric capacity piece 10, the bar electric capacity piece includes first end and second end, first end is passed through screw 11 fixed connection and is on first fixed electric capacity device clearance structure 14, first fixed electric capacity device clearance structure and cavity diapire fixed connection in, first end is close to the input harmonic oscillator, the second end is through second fixed electric capacity device clearance structure 15 and cavity inside wall fixed connection, the second end is 3.5mm to the interval of apron, the second end is 3.2mm to the distance of resonance post. The second fixed capacitor device clearance structure is an L-shaped connecting piece, and the horizontal part of the L-shaped connecting piece is fixedly connected to the top of the side wall of the cavity.

The third dimension 17 and the fourth dimension 18 of the present invention significantly reduce the size of the filter compared to the prior art, making it possible to select a straight row configuration.

As a preferred example of the present invention, the side of the second end facing the harmonic oscillator is coated with a polytetrafluoroethylene support 12 for achieving the purpose of capacitance waveform diagram by relative signal transmission.

The first fixed capacitor device clearance structure comprises a near end and a far end, the near end is connected with the first end through a screw, and the far end is connected with the side wall of the cavity.

As another preferred example of the present invention, the bottom of the proximal end is fixedly connected to the bottom of the cavity through a teflon fixing seat 13. Thus the structure is more firm.

The design scheme of the invention can be obtained by Auto CAD software and electromagnetic field simulation software, the tap chip 16 generates signals to the harmonic oscillator, the harmonic oscillator at the leftmost end can be called as an input harmonic oscillator, the harmonic oscillator at the rightmost end can be called as an output harmonic oscillator, and a pass band is formed from the input harmonic oscillator to the output harmonic oscillator. The structure of the straight discharge cavity is relatively simple to process, and indexes are easy to realize; the problem of signal sensitivity due to high frequency can be solved.

As shown in fig. 5, it can be seen that a transmission zero is finally generated in each of the left 1 and the right 2 in the filter to suppress the out-of-band spurious signals; therefore, the problem that the out-of-band stray on the left side and the right side cannot be simultaneously inhibited in a straight cavity mode due to the limitation of the shape structure is solved.

The first terminal is grounded and the second terminal is capacitively coupled by the size of the part and the distance between the resonant columns. The resonant column magnetic field is mainly concentrated on the highest face of the second end, so that the desired zero point is obtained.

Claims

1. A cavity filter in-line cavity type symmetrical capacitor device comprises: cavity (8) and be located harmonic oscillator (9) that are the straight line structure in the cavity, characterized by: the cavity is internally provided with a bar-shaped capacitor plate (10) which extends in parallel along the length direction of the cavity, the bar-shaped capacitor plate comprises a first end and a second end, the first end is fixedly connected to a first fixed capacitor device clearance structure (14) through a screw (11), the first fixed capacitor device clearance structure comprises a near end and a far end, the near end is connected with the first end through a screw, the far end is connected with the side wall of the cavity, the first fixed capacitor device clearance structure is fixedly connected with the inner bottom wall of the cavity, the first end is close to an input harmonic oscillator and is grounded, the second end is fixedly connected with the inner side wall of the cavity through a second fixed capacitor device clearance structure (15), the distance from the second end to the cover plate is 3.5mm, the distance from the second end to the harmonic oscillator is 3.2mm, and one side of the second end facing the harmonic oscillator is coated with a polytetrafluoroethylene support body (12), the second fixed capacitor device clearance structure is an L-shaped connecting piece, and the horizontal part of the L-shaped connecting piece is fixedly connected to the top of the side wall of the cavity.

2. The symmetrical capacitor device in the form of an inline cavity of a cavity filter as claimed in claim 1, wherein: the strip-shaped capacitor piece is a brass piece.

3. The symmetrical capacitor device of claim 1, wherein the capacitor device comprises: the bottom of the near end is fixedly connected to the bottom of the cavity through a polytetrafluoroethylene fixing seat (13).