CN102832429B - Coaxial cavity filter - Google Patents

Coaxial cavity filter Download PDF

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Publication number
CN102832429B
CN102832429B CN201210337699.1A CN201210337699A CN102832429B CN 102832429 B CN102832429 B CN 102832429B CN 201210337699 A CN201210337699 A CN 201210337699A CN 102832429 B CN102832429 B CN 102832429B
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Prior art keywords
ring bodies
cavity
tuning screw
cover plate
shirt rim
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CN201210337699.1A
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CN102832429A (en
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肖竞
王邦林
李钦
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Anhui Dafu Electromechanical Technology Co., Ltd.
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Shenzhen Tatfook Technology Co Ltd
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Abstract

The invention discloses a coaxial cavity filter, comprising a cavity, a cover plate for covering the cavity, a resonator arranged inside the cavity, and a tuning screw, wherein the resonator comprises a capacitance sheet and a rod body; the capacitance sheet is arranged at one end of the rod body; and one end of the tuning screw passes through the cover plate and the capacitance sheet in sequence and then are inserted into the cavity, and the other end of the tuning screw is fixed on the cover plate. Compared with the prior art, the cover plate of the coaxial cavity filter is additionally provided with the tuning screw which passes through the cover plate and the capacitance sheet in sequence to increase the capacitance of the whole resonant cavity, thus reducing the passband frequency of the resonant cavity; and under the condition of strictly restricting the size of the cavity filter, the above method is adopted to reduce the frequency without enlarging the resonant cavity or increasing the number of the resonant cavities, thus widening the tuning scope of the cavity filter and reducing the size of the filter as well.

Description

A kind of coaxial cavity filter
Technical field
The present invention relates to a kind of coaxial cavity filter.
Background technology
Microwave filter is widely used in the communications field as a kind of frequency selection device, in communication base station system, is mainly used in selecting signal of communication, the clutter outside filtering communication signal frequency or interference signal.Microwave filter can be divided into microstrip filter, interdigital filter, coaxial cavity filter, waveguide filter, pectinate line cavity filter, helical cavity filter, small-sized lumped wave filter, Ceramic Dielectric Filter, SIR (step impedance resonator) filter, high temperature superconducting materia etc. by transmission line classification.
Because coaxial cavity filter is very applicable to large-scale production, and cost is also very cheap, therefore, mostly adopts coaxial cavity filter in base station system.As depicted in figs. 1 and 2, coaxial cavity filter comprises cavity 1, cover plate 2, resonator 3 and tuning screw 4, and described resonator is fixed in described cavity, cavity described in described cover plate capping; Described resonator comprises capacitance sheet 5 and the body of rod 6, one end of described tuning screw penetrates the hollow space that described cover plate 2 and capacitance sheet 5 insert the described body of rod 6 successively, regulating described tuning screw to meeting radio-frequency (RF) index again, finally described tuning screw being fixed on described cover plate.
The resonant cavity of coaxial cavity filter generally can be equivalent to LRC resonant circuit, and according to coupled resonance microwave filter principle, the band connection frequency of coaxial cavity filter is determined by resonant cavity frequency, and resonant cavity frequency is as following formula: f = 1 2 π LC
From above formula, when resonant cavity size more hour, its electric capacity C just reduces, then band connection frequency is higher, otherwise then lower.In design of filter, when required band connection frequency requires very low, just need increase the size of resonant cavity or increase the quantity of resonant cavity, and this change all causing cavity body filter size is large; When having carried out clear and definite restriction to the size of described cavity, just can not meet the requirement of the size of low frequency and restriction simultaneously, namely can meet low band connection frequency, the size not increasing cavity can have been ensured again.
Summary of the invention
The present invention is that when in solution prior art, required band connection frequency requirement is lower, cavity body filter size becomes large defect, provides a kind of coaxial cavity filter.
For achieving the above object, the present invention is by the following technical solutions:
A kind of coaxial cavity filter, the cover plate comprising cavity described in cavity, capping and the resonator be located in described cavity, described resonator comprises capacitance sheet and the body of rod, described capacitance sheet is located at one end of this body of rod, it is characterized in that: also comprise tuning screw, described tuning screw one end penetrates described cover plate successively and described capacitance sheet inserts in described cavity, and the other end is fixed on described cover plate.
Described capacitance sheet comprises flange and shirt rim, described flange is stretched out by the end face of described body of rod one end and is formed, based on described flange edge along the described body of rod axially and deviate from described cover plate direction and extend to form, the described body of rod, flange and shirt rim are integral structures in described shirt rim.
The surface of described tuning screw and described flange contact portion is provided with insulating material.
Described tuning screw one end of inserting in described cavity is provided with tuning dish.
Described tuning dish is circular discs or square plate, one-body molded between described tuning dish and described tuning screw.
A kind of execution mode, between described shirt rim or described shirt rim be provided with the brace relative with described tuning screw between the body of rod.
Described capacitance sheet also comprises ring bodies, and described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, and the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
The second execution mode, described shirt rim be provided with the brace relative with described tuning screw between the body of rod, described brace is semicircle anchor ring.
Described capacitance sheet also comprises ring bodies, and described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, and the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
The third execution mode, described capacitance sheet also comprises ring bodies, and described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, and the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
The described body of rod is made up of the cylinder of multistage hollow, and described cylinder is coaxially connected successively, and the diameter of described cylinder diminishes from described cover plate gradually to cavity bottom.
Described cover plate is also provided with second tune screw rod, and described second tune screw rod one end penetrates described cover plate and inserts the hollow space of the described body of rod, and the other end is fixed on described cover plate.
A kind of coaxial cavity filter of the present invention, relative to above-mentioned prior art, described cover plate is set up a tuning screw, this tuning screw penetrates described cover plate and capacitance sheet successively, and and form electric capacity between the capacitance sheet of formation shirt rim, to increase the electric capacity of whole resonant cavity, thus reduce the band connection frequency of described resonant cavity; When size restrictions for cavity body filter is strict, use this kind of method, the mode by increasing resonant cavity or increase resonant cavity quantity can being avoided to reduce frequency, both having increased the tuning range of cavity body filter, having turn reduced the size of filter.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme in the embodiment of the present invention, below the accompanying drawing used required in describing embodiment is briefly described.
Fig. 1 is a kind of coaxial cavity filter floor map in prior art;
Fig. 2 is a kind of coaxial cavity filter cutaway view in prior art;
Fig. 3 is the embodiment of the present invention one one kinds of coaxial cavity filter floor map;
Fig. 4 is the embodiment of the present invention one one kinds of coaxial cavity filter cutaway views;
Fig. 5 is the coaxial cavity filter cutaway view that the embodiment of the present invention one one kinds is provided with tuning dish;
Fig. 6 is the first execution mode cutaway view of the embodiment of the present invention one one kinds of coaxial cavity filters;
Fig. 7 is the first execution mode extended mode cutaway view of the embodiment of the present invention one one kinds of coaxial cavity filters;
Fig. 8 is the embodiment of the present invention one one kinds of coaxial cavity filter the second execution mode cutaway views;
Fig. 9 is the embodiment of the present invention one one kinds of coaxial cavity filter the second execution mode extended mode cutaway views;
Figure 10 is the third execution mode cutaway views of the embodiment of the present invention one one kinds of coaxial cavity filters.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
Embodiment one provides a kind of coaxial cavity filter, as shown in Figure 3 and Figure 4, the cover plate 2 comprising cavity described in cavity 1, capping and the resonator 3 be located in described cavity, described cover plate is by cavity described in screw or bolt capping; Described resonator 3 comprises capacitance sheet 5 and the body of rod 6, and described capacitance sheet is located at one end of this body of rod, and is structure as a whole with this body of rod, and the described body of rod is fixed in described cavity by screw or bolt-locking, or one-body molded with described cavity; This coaxial cavity filter also comprises tuning screw 9, and one end of described tuning screw 9 penetrates described cover plate 2 successively and described capacitance sheet 5 inserts in described cavity, and the other end is fixed on described cover plate by screw or bolt-locking.
Described capacitance sheet 5 comprises flange 7 and shirt rim 8, and described flange 7 is stretched out by the end face of described body of rod one end and formed, described shirt rim 8 based on described flange edge along the described body of rod axially and deviate from described cover plate direction and extend to form.
Tuning screw 9 penetrates described cover plate and flange successively and stretches in described cavity, do not contact mutually between described tuning screw 9 with described flange 7, namely both do not conduct, direct-to-ground capacitance could be formed, in the present embodiment, the surface of described tuning screw and described flange contact portion is provided with insulating material, and as insulating material such as bag one deck polyvinyl fluorides, the part that equally also can contact with tuning screw at flange does insulation processing.Also can through hole flange inserting tuning screw be done greatly, to strengthen the space between described flange and described tuning screw, thus avoid conducting between flange and tuning screw.Certainly, aforesaid way is only the present embodiment and realizes the mode that flange and tuning screw insulate, and those skilled in the art can require take different insulation modes according to actual techniques in actual applications.
When the body of rod is cylindric, described flange is preferably annular dish, and when the described body of rod is the square cylinder of hollow, described flange is preferably square annular disk.Certainly, the not mode coordinated of the side's of eliminating annular flange flange dish and the cylindric body of rod or other fit systems.
Described shirt rim is coaxial with the described body of rod, and according to prior art and actual conditions, described shirt rim and the described body of rod are generally coaxial, but run into special circumstances, does not get rid of out-of-alignment situation and also can reach identical effect or better effect.
Described tuning screw has one at least, in the present embodiment, described tuning screw preferably one, in other embodiments, according to the specific requirement of concrete radio-frequency (RF) index and client, when band connection frequency as required is extremely low, in order to limit the size of cavity, two or more tuning screw can be set, to increase the electric capacity of whole resonant cavity, thus reduce band connection frequency; When arranging two tuning screws.
As shown in Figure 5, in order to increase capacitance, be provided with tuning dish in described tuning screw one end of inserting in described cavity, the capacitance of the increase needed for being formed between described tuning dish and described flange, capacitance changes with the distance between described tuning screw and flange and changes.
Preferably, described tuning dish is circular discs or square plate, one-body molded between described tuning dish and described tuning screw, and the tuning dish of other shapes is not formed this restriction of the present invention.One-body molded between described tuning dish and described tuning screw, namely both are seamless connections, and certainly, described tuning dish and the described Split type structure that is tuned as also can realize.
When the resonance frequency required is extremely low, and when not increasing again cavity size, can reduce resonance frequency by the mode reloading capacitance sheet, be below three kinds of execution modes.
The first execution mode, as shown in Figure 6, is provided with the brace 11 relative with described tuning screw between described shirt rim 8 or between described shirt rim 8 with the body of rod 6.Then form electric capacity between the tuning dish 10 of described tuning screw and described brace.
Electric capacity can be reloaded on the basis increasing brace, it is implemented as shown in Figure 7, described capacitance sheet also comprises ring bodies 12, described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.Described ring bodies can the side's of being ring bodies, also can circular body.
The second execution mode, as shown in Figure 8, described shirt rim be provided with the brace 11 relative with described tuning screw between the body of rod, described brace is semicircle anchor ring.Namely described brace contacts with the described body of rod, and is semicircle anchor ring.
Described capacitance sheet also comprises ring bodies 12, and as shown in Figure 9, described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, and the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.Described ring bodies can the side's of being ring bodies, also can circular body.
The third execution mode, can not add on the basis of brace, directly add ring-type capacitance sheet, as shown in Figure 10, described capacitance sheet also comprises ring bodies 12, and described ring bodies is connected with described flange, and described ring bodies and described shirt rim are coaxially arranged, the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.Described ring bodies can the side's of being ring bodies, also can circular body.
In the present embodiment, the described body of rod has following two kinds of execution modes:
A kind of execution mode, as shown in Figure 4, the described body of rod 6 is cylinders of hollow, and it is by screw or be bolted in described cavity, or by machining and described cavity one-body molded; Described machining is that lathe is directly processed or formed by compression mod die casting.
Preferably, the described body of rod is the cylinder of hollow, or square cylinder.
Another kind of execution mode, the described body of rod 6 is made up of the cylinder of multistage hollow, and described cylinder is coaxially connected successively, and the diameter of described cylinder diminishes from described cover plate gradually to cavity bottom.
Preferably, the described body of rod is made up of the cylinder of two sections of hollows, or is made up of the square cylinder of two sections of hollows; According to different embodiments, cylinder or the square cylinder composition of more than three sections or three sections also can be adopted.
Described cover plate is also provided with second tune screw rod 4, second tune screw rod 4 described here is distinguished mutually with described tuning screw 9, one end of described second tune screw rod penetrates described cover plate and inserts the hollow space of the described body of rod, and the other end is fixed on described cover plate by screw or bolt-locking.
For the present embodiment, the length of described tuning screw is longer than the length of second tune screw rod; Because required band connection frequency is lower, the body of rod and the described shirt rim that need more tuning screw form electric capacity, thus increase the electric capacity of whole resonant cavity, to realize the reduction of frequency.
Described coaxial cavity filter is duplexer, mixer, tower amplifier or anti-interference filter.
A kind of coaxial cavity filter of the present invention, relative to above-mentioned prior art, described cover plate is set up a tuning screw, this tuning screw penetrates described cover plate and capacitance sheet successively, and and form electric capacity between the capacitance sheet of formation shirt rim, to increase the electric capacity of whole resonant cavity, thus reduce the band connection frequency of described resonant cavity; When size restrictions for cavity body filter is strict, use this kind of method, the mode by increasing resonant cavity or increase resonant cavity quantity can being avoided to reduce frequency, both having increased the tuning range of cavity body filter, having turn reduced the size of filter.
Apply specific case herein to set forth principle of the present invention and execution mode, the explanation of above embodiment just understands method of the present invention and core concept thereof for helping; Meanwhile, for those of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.

Claims (10)

1. a coaxial cavity filter, comprise cavity, the cover plate of cavity described in capping and the resonator be located in described cavity, described resonator comprises capacitance sheet and the body of rod, described capacitance sheet is located at one end of this body of rod, described cover plate is also provided with second tune screw rod, described second tune screw rod one end penetrates described cover plate and inserts the hollow space of the described body of rod, the other end is fixed on described cover plate, it is characterized in that: also comprise tuning screw, described capacitance sheet comprises flange and shirt rim, described flange is stretched out by the end face of described body of rod one end and is formed, described shirt rim based on described flange edge along the described body of rod axially and deviate from described cover plate direction and extend to form, the flange portion that described tuning screw one end penetrates described cover plate and described capacitance sheet successively inserts in described cavity, the other end is fixed on described cover plate, electric capacity is formed between the shirt rim of described tuning screw and described capacitance sheet.
2. coaxial cavity filter according to claim 1, is characterized in that: the surface of described tuning screw and described flange contact portion is provided with insulating material.
3. coaxial cavity filter according to claim 1, is characterized in that: described tuning screw one end of inserting in described cavity is provided with tuning dish.
4. coaxial cavity filter according to claim 3, is characterized in that: described tuning dish is circular discs or square plate, one-body molded between described tuning dish and described tuning screw.
5. the coaxial cavity filter according to claim 1 or 3, is characterized in that: between described shirt rim or described shirt rim be provided with the brace relative with described tuning screw between the body of rod.
6. coaxial cavity filter according to claim 5, it is characterized in that: described capacitance sheet also comprises ring bodies, described ring bodies is connected with described flange, described ring bodies and described shirt rim are coaxially arranged, the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
7. the coaxial cavity filter according to claim 1 or 3, is characterized in that: described shirt rim be provided with the brace relative with described tuning screw between the body of rod, described brace is semicircle anchor ring.
8. coaxial cavity filter according to claim 7, it is characterized in that: described capacitance sheet also comprises ring bodies, described ring bodies is connected with described flange, described ring bodies and described shirt rim are coaxially arranged, the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
9. the coaxial cavity filter according to claim 1 or 3, it is characterized in that: described capacitance sheet also comprises ring bodies, described ring bodies is connected with described flange, described ring bodies and described shirt rim are coaxially arranged, the diameter of described ring bodies is less than the diameter of described shirt rim, and described tuning screw is positioned at described ring bodies.
10. coaxial cavity filter according to claim 1, is characterized in that: the described body of rod is made up of the cylinder of multistage hollow, and described cylinder is coaxially connected successively, and the diameter of described cylinder diminishes from described cover plate gradually to cavity bottom.
CN201210337699.1A 2012-09-13 2012-09-13 Coaxial cavity filter Active CN102832429B (en)

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CN103280617B (en) * 2013-05-15 2015-04-01 成都联帮微波通信工程有限公司 Small cavity filter
CN104916888A (en) * 2015-05-14 2015-09-16 中国电子科技集团公司第四十一研究所 High-power filter
CN106229592A (en) * 2016-09-20 2016-12-14 中国电子科技集团公司第五十四研究所 A kind of low-frequency range cavity band-pass filter
CN110534854A (en) * 2019-07-26 2019-12-03 苏州诺泰信通讯有限公司 A kind of Novel Filter frequency reducing structure
CN113745780B (en) * 2020-05-29 2022-10-28 华为技术有限公司 Cavity filter and communication equipment

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CN101764277A (en) * 2010-03-12 2010-06-30 深圳市大富科技股份有限公司 Filter of cavity and resonance tube thereof
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CN102122742A (en) * 2010-12-02 2011-07-13 宁波泰立电子科技有限公司 Cavity filter with rotary coupling regulation structure
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CN202178351U (en) * 2011-07-14 2012-03-28 凯镭思通讯设备(上海)有限公司 Coaxial cavity filter capable of changing resonant frequency

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Effective date of registration: 20180730

Address after: 233400 Huaiyuan County Economic Development Zone, Bengbu, Anhui

Patentee after: Anhui Dafu Electromechanical Technology Co., Ltd.

Address before: 518104 First, Second and Third Floors of A1, A2, A3 101, A4 of Shajing Street, Shajing Street, Baoan District, Shenzhen City, Guangdong Province

Patentee before: Shenzhen Tat Fook Technology Co., Ltd.