K波段宽带圆极化器设计  

A Design of a K-Band Circular Polarizer

作　　者：王海伦[1] 李斌[1] 

机构地区：[1]中国科学院上海天文台,上海200030

出　　处：《天文研究与技术》2015年第4期455-460,共6页Astronomical Research & Technology

基　　金：国家自然科学基金(11078003);国家高技术研究发展计划(2012AA121603);上海市科学技术委员会科研计划项目(08DZ1160100)资助

摘　　要：设计了一个K波段圆极化器,其工作频率为18至26.5 GHz。K波段包含多条重要的射电天文分子谱线,此波段圆极化器的研制对于天文观测与科学研究有极其重要的意义。圆极化器用于将线极化波转换为圆极化波以便于射电望远镜进行观测。包括其工作原理、设计要点、模型仿真结果等内容。主要着眼于正交模式转换器与移相器这两个圆极化器中的重要器件,通过工作原理分析以及电磁仿真的方法进行器件的具体设计并得出仿真结果。仿真结果各个端口回波损耗均小于-20 d B,且移相器的移相误差小于3.3°。In this paper we present a design of a circular polarizer working in the K band.More specifically, it works in the frequency range of 18GHz to 26.5GHz.There are many important spectral lines in the K band, so that a design of a circular polarizer working in this band can highly significantly facilitate astronomical observation and scientific research.The circular polarizer is used to transform linearly polarized signals received by a feed to circularly polarized signals for the convenience of radio-telescope observation.We describe the principle, key aspects, simulation results, and other relevant issues about the design.Our descriptions mainly cover two important devices, the orthogonal mode transducer （ OMT ） and the phase shifter.The OMT is used to separate signals in modes orthogonal to each other, and the phase shifter is used to induce a phase difference of 90 degrees between signals of two such modes.By combining the two devices and a twisted waveguide of square cross sections and a twist angle of 45 degrees, we construct a K-band circular polarizer.Based on the principle and 3D electromagnetic simulations we specify the details of the design.Our simulations show that the losses of the OMT and phase shifter are both less than-20dB, and the error of phase shifting by the phase shifter is less than 3.3 degrees.We finally show some simulation results of the entire system of the circular polarizer .

关 键 词：圆极化器 正交模式转换器 移相器 K波段 

分 类 号：TN609[电子电信—电路与系统]