四阶双模介质滤波器的设计和分析

理论分析了屏蔽腔中矩形介质的谐振频率，同时使用Ansoft HFSS对所设计的滤波器进行仿真分析。根据以往的双模结构，使用了利用切角进行双模耦合的新结构，对相邻腔体问的耦合采用耦合窗口和耦合杆相结合的方法。要求的滤波器参数指标为：中心频率f0=2140MHz，带宽BW=50MHz，插入损耗IL〈0．1dB，回波损耗RL〉22dB。仿真结果表明该结构可以更加有效地减小插入损耗，且体积比传统滤波器减小了很多，有利于器件小型化。

Structure design and analysis of a 4th-degree dielectric dual-mode filter

The paper introduces the design principle and calculation method of 4th-degree dielectric dual-mode filter with two cavities. The resonant frequency of dielectric square resonator located in a rectangular shield is analyzed theoretically. Meanwhile the designed structure is simulated by Ansoft HFSS. The filter uses chamfer to couple dual resonant mode and utilizes coupling rod combined with iris coupling window to couple two cavities. The required parameters of the microwave band-pass filter are as follows： center frequcncyfi=2 140 MHz, bandwidth BW=50 MHz, insertion loss IL〈0.1 dB, and return loss RL〉22 dB. According to the result of simulation, the filter can reduce the insert loss and dimension efficiently. It is one of the most effective means for miniaturizing a band-pass filter.