基于Turnstile结构的超宽带正交模耦合器研究

摘要

Ortho⁃mode transducer ( OMT ) is a very important passive component in a reflector antenna feed system. The bandwidth of the ortho⁃mode transducer determines the bandwidth of the antenna and its performance directly affects the performance of the receiver.In order to meet the need of Q band (30~50 GHz) cryogenic receiver for Xinjiang Astronomical Observatory,the OMT based on Turnstile structure is described,which has public port based circular waveguide and two branch ports based on standard rec⁃tangular waveguide.The ortho⁃mode transducer is designed and optimized for the Q band (30~50 GHz) by electromagnetic simulation software HFSS.Simulation results indicate the return loss is better than -22 dB,the orthogonal isolation is better than -46 dB within 50% relative bandwidth.The study provides theoretical design basis for further research of millimeter wave broadband OMT.%正交模耦合器是反射面天线馈源系统中非常重要的无源器件，正交模耦合器的带宽决定了天线的工作带宽，其性能直接影响接收机的性能。为满足新疆天文台Q波段（30～50 GHz）制冷接收机的需求，描述了Turnstile结构的正交模耦合器，公共端口为圆波导，2个分支端口为标准矩形波导。应用电磁仿真软件HFSS对正交模耦合器进行了设计与优化。仿真结果表明，在50％相对带宽内，回波损耗优于－22 dB，正交隔离度优于－46 dB。为进一步开展毫米波宽带OMT的研究提供了理论设计基础。