基于双模谐振器的对称零点滤波器设计

Design of Symmetric Zeros Filter based on Dual-mode Resonator

设计了一种双模谐振器,并在双模谐振器的基础上,通过理论计算与仿真分析,使用微波仿真软件ADS/HFSS设计了一种对称零点介质多模滤波器,分析各模式的电场特性,利用金属螺钉微扰的方式实现了模式之间的相互耦合。加入调谐螺钉的方式,改变了模式的电场分布。两个耦合简并模的作用相当于两个耦合谐振器,从而在保持谐振回路不变的情况下,使谐振器的个数呈几何级数减少。例如,可以利用一个谐振器的两个模式在一个传统的n节滤波器的物理空间实现2n节滤波器的特性,从而大大减小滤波器的体积。利用单腔双模实现了两阶滤波器的设计,并在通带两侧实现两个传输零点,提高了滤波器的带外抑制能力。结果显示,通带内回波损耗>20dB,插入损耗<0.25dB,通带左侧的零点为3.13GHz,通带右侧的零点为3.67GHz,驻波比<1.21。该滤波器具有插入损耗小、体积小以及带外抑制性能好的优点。

A dual-mode resonator is designed,and on the basis of dual-mode resonator,through theoretical calculation and simulation analysis,a symmetrical zero dielectric multi-mode filter is designed by using ADS/HFSS simulation software,and the electric field characteristics of each mode are analyzed.The mutual coupling between modes is realized by metal screw perturbation,and the electric field distribution of the mode is changed by adding the tuning screw.The function of two coupled degenerate modes is equivalent to two coupled resonators,so that the number of resonators can be reduced greatly while keeping the resonance loop unchanged.For example,the characteristics of 2n section filter can be realized in the physical space of a traditional n section filter by using dual-mode of a resonator,so that the volume of the filter can be greatly miniaturized.The design of the two-order filter is realized by using single cavity and dual-mode,and two transmission zeros are realized on both sides of the pass-band,which improves rejection ability of the filter in the outside of pass-band.The results show that the return loss in the pass-band is more than 20 dB,the insertion loss is less than 0.25 dB,the zero point on the left side of the pass-band is 3.13 GHz while the zero point on the right side of the pass-band is 3.67GHz,and the SWR(standing wave ratio)is less than 1.21 in the pass-band.The filter has the advantages of small insertion loss,small size and good suppression in the outside of pass-band。