阅读说明：本技术 一种在带外引入双传输零点的宽带滤波器 (It is a kind of with it is outer introduce dual transfer zero broadband filter ) 是由 刘贤栋 孙玲玲 于 2019-07-16 设计创作，主要内容包括：本发明公开了一种在带外引入双传输零点的宽带滤波器,本发明对传统的1/4波长谐振器进行改进,宽带滤波器的线耦合馈电点在谐振器上的任意位置,谐振器之间的耦合强度由耦合位置决定；谐振器开路端空置,方便在不相邻的两个谐振器开路端之间引入缝隙耦合式的交叉耦合,从而在滤波器带外插入传输零点,解决了传统1/4波长宽带滤波器难插入传输零点的弊端；本发明引入的交叉耦合,只需一个交叉耦合就可以得到两个传输零点,而传统的交叉耦合方式一个交叉耦合只有一个传输零点。(The invention discloses a kind of with the outer broadband filter for introducing dual transfer zero, the present invention improves 1/4 traditional wave resonator, the any position of the line couple feed point of broadband filter on the resonator, the stiffness of coupling between resonator are determined by coupling position；Resonator open end is vacant, the convenient cross-coupling that slot-coupled formula is introduced between non-conterminous two resonator open ends, to be inserted into transmission zero outside filter band, solves the drawbacks of traditional 1/4 wavelength broadband filter difficulty insertion transmission zero；Present invention introduces cross-coupling, only a cross-coupling is needed to can be obtained by two transmission zeros, and the cross-coupling of traditional cross-coupled manner one only one transmission zero.)

1. it is a kind of with it is outer introduce dual transfer zero broadband filter, it is characterised in that: to 1/4 traditional wave resonator into Row improves, any position of the line couple feed point of broadband filter on the resonator, and the stiffness of coupling between resonator is by coupling Coincidence sets decision, and coupling position couples weaker closer to short-circuit end；Resonator open end is vacant, in non-conterminous two resonance The cross-coupling that slot-coupled formula is introduced between device open end, to be inserted into transmission zero outside filter band.

2. according to claim 1 a kind of with the outer broadband filter for introducing dual transfer zero, it is characterised in that: resonance The open end and short-circuit end of device all carry out folding.

3. according to claim 1 or 2 a kind of with the outer broadband filter for introducing dual transfer zero, it is characterised in that: The resonator coefficient of coup is K, K=| (f₁ ²-f₂ ²)/(f₁ ²+f₂ ²)|；Wherein f_1、f₂For the resonance frequency of resonator.

Technical field

The present invention relates to frequency microwave field, specially a kind of method that transmission zero is introduced outside broadband filter band, For a kind of new construction broadband filter.

Background technique

Filter is widely applied in communication system, and bandpass filter is used to inhibit to guarantee receiver with outer high reject signal Signal-to-noise performance.Filter wide variety is divided into microstrip filter, metal cavity filter, guide filter with processing technology Device, multilayer low temperature public affairs burn ceramic filter (LTCC), SAW filter etc.；It is divided into four major class, bandpass filtering with filter function Device, bandstop filter, low-pass filter, high-pass filter, different filters are applied to unused occasion.Microstrip filter exists Filter field is very extensive, and planar structure, easily with the characteristics of other circuit integrations obtains microstrip filter at miniaturization Extensive research.

Currently, many communication equipments, such as mobile base station, vehicle communication system, Radar-Communication etc. require wideband filtered Device come inhibit band outside interference, system is to the rejection of out-of-band interference signal, nearby pass interference signal by filter rectangle Coefficient determines that for squareness factor closer to 1, the anti-out-of-band interference ability of system is stronger.The method for improving filter squareness factor has two Kind, the first is to increase filter order, but increase order and will increase the insertion loss of filter, and increase cost, the Two kinds of methods are with outer insertion transmission zero in the way of cross-linked, and transmission zero can greatly improve filter rectangle Degree, second method do not increase the order of filter, do not increase the cost of manufacture of filter.

Most common wideband microband filter mainly uses 1/4 wave resonator, 1/4 wave coupled-line of open end The mode of coupling realizes, the coefficient of coup between the input and output Q value resonator of broadband filter by coupling line line width and Resonator line width determines.This filter construction is simple, technology maturation, but utilizes cross-coupled manner in broadband filter band When outer insertion zero point, cross-coupling line can be with interior introducing secondary or even higher order resonances point, therefore is difficult with classical intersection Coupling technique is inserted into transmission zero outside broadband filter band.

Summary of the invention

Aiming at the problem that 1/4 traditional wavelength broadband filter can not be inserted into out-of-band transmission zero point, the present invention mentions the present invention It is a kind of with the outer broadband filter for introducing dual transfer zero out, filter square can be improved with outer insertion dual transfer zero Shape coefficient improves system rejection to disturbance ability.

The present invention is a kind of with the outer broadband filter for introducing dual transfer zero, and the present invention is to 1/4 traditional wave resonance Device improves, any position of the line couple feed point of broadband filter on the resonator, the stiffness of coupling between resonator It is determined by coupling position, coupling position couples weaker closer to short-circuit end；Resonator open end is vacant, at non-conterminous two The cross-coupling that slot-coupled formula is introduced between resonator open end, to be inserted into transmission zero outside filter band；It avoids Line is coupled in broadband the drawbacks of generating secondary or higher order resonances point；The resonator coefficient of coup is K, K=| (f₁ ²-f₂ ²)/(f₁ ²+ f₂ ²) |, wherein f_1、f₂For the resonance frequency of resonator.

Preferably, the open end and short-circuit end of resonator all carry out folding.

The beneficial effects of the present invention are:

1) 1/4 traditional wave resonator is redesigned, has obtained a kind of can be used for the new humorous of broadband filter It shakes device structure, the stiffness of coupling between resonator can be determined by coupling position, reduce design difficulty to a certain extent.

2) a kind of cross-linked method of wideband microband filter insertion is proposed, is not increasing filter order, is not increasing In the case where big filter insertion loss, in the case where not influencing with interior transmission performance, 2 band unofficial biography are introduced to broadband filter Defeated zero point, the dual transfer zero greatly improve the squareness factor of filter, enhance the anti-interference ability of system.

3) present invention introduces cross-coupling, only a cross-coupling is needed to can be obtained by two transmission zeros, and it is traditional The cross-coupling of cross-coupled manner one only one transmission zero.

Detailed description of the invention

Fig. 1 new construction resonator

The relationship of Fig. 2 new construction resonator coupling position and the coefficient of coup

The cross-coupling of the non-conterminous resonator inserted into gap manifold type of Fig. 3

Fig. 4 broadband filter schematic diagram

The emulation of Fig. 5 broadband filter S parameter

Fig. 6 introduces cross-coupling

The relationship of Fig. 7 cross-coupling gap width and transmission zero location

Fig. 8 dual transfer zero and compare without transmission zero filter S parameter

The final domain of Fig. 9 broadband filter

The comprehensive coupling matrix out of table 1

2 filter design parameter of table (unit: mm)

Specific embodiment

The present invention is further illustrated in the following with reference to the drawings and specific embodiments.

As shown in Figure 1, it is a kind of in the broadband filter with outer introducing dual transfer zero, to 1/4 traditional wave resonator Improve, any position of the line couple feed point of broadband filter on the resonator, the stiffness of coupling between resonator by Coupling position determines that coupling position couples weaker closer to short-circuit end；As shown in Fig. 2, resonator coefficient of coup K is with coupling position The relationship of variation is set, K=| (f₁ ²-f₂ ²)/(f₁ ²+f₂ ²) |, wherein f_1、f₂For the resonance frequency of resonator；Resonator open end is empty It sets, the cross-coupling of slot-coupled formula is introduced between non-conterminous two resonator open ends, thus in filter band extrapolation Enter transmission zero, as shown in figure 3, avoiding line is coupled in broadband the drawbacks of generating secondary or higher order resonances point.

By taking the design of the 10 rank broadband filters of a 800-1600MHz as an example, technical solution of the present invention is illustrated:

Software tool for implementation is: filter synthesis tool CoupleFil 1.26, circuit simulating software Advanced Design System 2017 (ADS2017), 3D Electromagnetic Simulation and domain Software for producing sonnet 15.54.It is micro- Band plate is rogers3006, and thickness 0.635mm, dielectric constant er are 6.15, and dielectric loss angle is 0.002 10GHz.

Specific step is as follows:

Step 1, the coefficient of coup that 10 rank filters are calculated using filter synthesis tool and input and output feed Q value, are obtained To coupling matrix, table 1.

Step 2, the wire length C0 and line width W0 for calculating 1/4 wavelength, 50 ohm transmission line, resonator line wire length and it is wide according to Secondary is L1-L10, W1~W9, Fig. 4, and C0, W0 40mm, 0.86mm, for filter using symmetric design, general broadband filter is defeated It is maximum to enter output stage stiffness of coupling, so W1, W10 take 0.5mm, W2-W9 to take 0.8mm, L1-L10 initial value takes 40mm.

Step 3, the coupling matrix obtained by the first step determine that input is defeated with reference to the relational graph of m in Fig. 2 and coefficient of coup K The initial position that feed initial position couples on each resonator with coupling line, the i.e. value of m1-m10 out, Fig. 4.

Step 4 optimizes schematic diagram, obtains one at this time without the broadband filter with outer zero point, Fig. 5, by emulating As a result the squareness factor that 30dB:3dB can be calculated is 1.22.

Step 5 is inserted into cross-coupling between the symmetrical second level and the 9th grade of resonator, and Fig. 6 couples the length in gap It is set to 4mm, adjusts gap width to adjust cross coupling strength, Fig. 7 shows cross-coupling gap between 0.05mm-0.3mm The variation of transmission zero location when variation.

Step 6 determines that cross-coupling gap size is, then long 4mm, wide 0.1mm again advanced optimize domain, make It obtains band standing internal wave and is less than -20dB, Fig. 8, the Comparative result in simulation result and step 4, the squareness factor of filter is mentioned by 1.22 Height is to 1.13.

Step 7 carries out 3D Electromagnetic Simulation to the broadband filter using sonnet, and optimization obtains domain to the end, Fig. 9, The filter final size is shown in Table 2.

Table 1

L1	30.81	M1	30.69
				L2	25.26	M2	21.71
L3	28.99	M3	18.41
				L4	29.3	M4	15.51
L5	29.31	M5	18.74
				L6	29.31	M6	18.74
L7	29.3	M7	18.41
				L8	28.99	M8	18.41
L9	25.26	M9	21.71
				L10	030.81	M10	30.69
W1,W10	0.5	W2-W9	0.8
				C0	35	W0	0.86

Table 2

The above is only embodiments of the present invention, and the present invention proposes a kind of 1/4 wave resonator of new construction, is proposed A kind of method adding zero point to broadband filter, proposing a kind of new construction, there is the new construction broadband of out-of-band transmission zero point to filter Wave device, it is noted that, without departing from the inventive concept of the premise, can be with for those skilled in the art Several improvements and modifications are made, for example the new construction resonator and coupled modes are applied on the filter of other techniques or answered For narrow band filter, or cross-coupling etc. is introduced between other non-conterminous resonators, these improvements and modifications also should be regarded as In the scope of the present invention.