一种基于耦合矩阵的微带线带通滤波器的设计方法

提出了一种微带线带通滤波器的分步式设计方法，首先根据电性能指标得出耦合矩阵，然后采用谐振器、电耦合以及磁耦合等不同结构实现耦合矩阵的各个单元．该方法可直接综合出对称特性、非对称特性类椭圆函数滤波器的耦合矩阵，不仅适用于微带类椭圆函数滤波器的设计，也可应用到同轴腔、圆柱腔等形式滤波器的设计中．设计并研制了一台S波段180MHz带宽的6阶微带类椭圆函数滤波器，带内损耗起伏小于2．5dB，1957MHz及2327MHz处的抑制大于55dB，测试结果与设计值吻合较好，证实方法简单有效．

Design Method for Microstrip Bandpass Filters Based on Coupling Matrix

A multi-step design method for microstrip bandpass filters is presented.Firstly,a coupling matrix is obtained through the electric performance requirements of the bandpass filter.Secondly,different structures such as resonators,electric coupling and magnetic coupling are used to realize each unit of the coupling matrix.The method can directly synthesize the coupling matrix for symmetric and asymmetric quasi-elliptic function filter,not only suitable for designing microstrip bandpass filter,but also for designing coaxial or cylindrical cavity filter.An S-band 6-pole quasi-elliptic function microstrip filter is designed and realized with 180 MHz bandwidth,and its performances are as follows: the loss variation within band is less than 2.5 dB,the rejection at 1 957 MHz and 2 327 MHz is more than 55 dB,and the measured data agree well with the predicted values.The design method is proved simple and valid.