CN201725861U

CN201725861U - Cavity filter

Info

Publication number: CN201725861U
Application number: CN2010202512139U
Authority: CN
Inventors: 崔立成; 纪海翔; 吕维镇; 张少波
Original assignee: Shenzhen City Weifu Communication Technology Co Ltd
Current assignee: Shenzhen City Weifu Communication Technology Co Ltd
Priority date: 2010-06-29
Filing date: 2010-06-29
Publication date: 2011-01-26
Anticipated expiration: 2020-06-29

Abstract

The utility model discloses a cavity filter, which comprises at least three cavities, a connector and coupling windows, wherein the three cavities are sequentially connected via the coupling windows, any three continuous cavities are arranged at right angles; and one end of the connector is connected with the cavity, and the other end thereof is connected with input signals. With the utility model, any three continuous TM model medium cavities can be vertically arranged, and parasitic passing bands can be effectively restrained by the distribution characteristics of secondary-model and third-model magnetic fields.

Description

A kind of cavity body filter

Technical field

The utility model relates to a kind of filter, in particular a kind of cavity body filter.

Background technology

TM mould dielectric filter, compare with the metal coupling coaxial cavity filter, with under the volume, the cavity nonloaded Q is higher, the filter passband Insertion Loss is littler, and is nearer but shortcoming is higher mode (i.e. second and above mode of resonance) frequency distance basic mode (first mode of resonance) frequency of TM mould dielectric resonant chamber.Usually, the higher mode frequency of metal coaxial cavity and basic mode frequency ratio are more than 3.0, and TM mould dielectric filter has only about 1.5.As shown in Figure 1, microwave cavity forms the parasitic passband 2 of filter owing to the existence of higher mode, and parasitic passband 2 then is that band pass filter 1 does not wish to exist.In order to suppress parasitic passband 2, usually at front or low pass filter 3 of back cascade of band pass filter 1, finally obtaining one does not have parasitic band logical 4.

Because the parasitic passband of TM dielectric filter is closer apart from passband, use low pass filter directly to suppress, there is following shortcoming:

1) the low pass filter size will be bigger, brings higher cost and take more filter space;

2) design difficulty of low pass filter is big, and the passband Insertion Loss increases;

Therefore, prior art has yet to be improved and developed.

The utility model content

The purpose of this utility model is to provide a kind of project organization that does not use low pass filter and only change cavity to come the parasitic passband of rejects trap.

The technical solution of the utility model is as follows:

A kind of cavity body filter comprises cavity, connector and coupling window, and described cavity connects successively by coupling window, and wherein, described cavity is at least 3, and wherein, any 3 continuous cavitys are arranged and are arranged to the right angle; Described connector one end connects cavity, and the other end connects input signal.

Described cavity body filter, wherein, described cavity is set to 6, and the first, second, third, fourth, the 5th and the 6th cavity connects successively, and wherein the 3rd, the 4th and the 5th cavity is formed a right angle.

The beneficial effects of the utility model: the utility model by will be arbitrarily three continuous TM mould medium cavitys structurally be arranged to vertical arrangement, utilize the characteristic of two apotypes and three apotype Distribution of Magnetic Field to suppress parasitic passband effectively.

Description of drawings

Fig. 1 is the structural representation of existing inhibition parasitic passband;

Fig. 2 is the structural representation of cavity body filter of the present utility model;

Fig. 3 is the filtering function schematic diagram of cavity body filter of the present utility model.

Embodiment

For making the purpose of this utility model, technical scheme and advantage clearer, clear and definite, below the utility model is further described with reference to the accompanying drawing embodiment that develops simultaneously.

Referring to Fig. 2, cavity body filter 10 of the present utility model, comprise first cavity 11, second cavity 12, the 3rd cavity 13, the 4th cavity 14, the 5th cavity 15, the 6th cavity 16 that are arranged in the cavity body filter 10, connect coupling window 18 and first connector 17 that is connected with the outside and second connector 19 of cavity and cavity.In the present embodiment, the 3rd cavity 13, the 4th cavity 14, the 5th cavity 15 are arranged in a right angle, first cavity 11 of signal in first connector 17 is input to cavity body filter 10, then successively through second, third, after the filtration of the 4th, the 5th, the 6th cavity from 19 outputs of second connector.

Adopt the cavity body filter 10 of said structure the parasitic passband of pass filter can be filtered, and need not increase low pass filter of design, not only reduce the difficulty of manufacture craft and can also save cost.The principle of the cavity body filter 10 of said structure is: the secondary of TM mould dielectric resonant chamber and the frequency of three apotypes are about 1.5 times of basic mode frequency, and the frequency of four times and five apotypes is about 2.5 times of basic mode frequency.Because four times and five apotypes are far away apart from basic mode, influence a little less than, examine of the influence of three apotypes so only consider secondary to dielectric filter.Wherein, the resonance frequency of secondary and three apotypes is identical, and Distribution of Magnetic Field structurally is a quadrature.According to Distribution of Magnetic Field, two apotypes can only with the coupling of up and down cavity, can not with about the cavity coupling, three apotypes can only with about cavity coupling, can not be coupled with cavity up and down, therefore pass through to change the setting of cavity syndeton, thereby eliminate two apotypes and three apotypes inhibition parasitic passband.

As shown in Figure 3, when in the filter during any three continuous cavity vertical arrangement, what suppose horizontal direction is two apotypes (shown in the dotted lines), vertical direction be three apotypes (shown in the solid lines), to cavity N, two apotypes can not be coupled from cavity N-1, and three apotypes can be coupled, but to cavity N+1, three apotypes can not be coupled from cavity N.

That is to say that the signal of two, three apotype frequencies, has not just had to cavity N+1 to cavity N from cavity N-1 again.And then structurally parasitic passband has been carried out suppressing effectively.

Arrange by cavity, can suppress the secondary and the three apotype frequencies of TM mode resonant cavity effectively, thereby reduced the design difficulty of low pass filter, perhaps cancel the use of low pass filter.

Should be understood that; application of the present utility model is not limited to above-mentioned giving an example; for those of ordinary skills, can be improved according to the above description or conversion, all these improvement and conversion all should belong to the protection range of the utility model claims.

Claims

1. a cavity body filter comprises cavity, connector and coupling window, and described cavity connects successively by coupling window, it is characterized in that, described cavity is at least 3, and wherein, any 3 continuous cavitys are arranged and are arranged to the right angle; Described connector one end connects cavity, and the other end connects input signal.

2. cavity body filter according to claim 1 is characterized in that described cavity is set to 6, and the first, second, third, fourth, the 5th and the 6th cavity connects successively, and wherein the 3rd, the 4th and the 5th cavity is formed a right angle.