中文摘要：

天马望远镜Ka波段宽带接收机是研究恒星形成、星际介质以及深空探测的重要观测平台。论述了接收机核心器件Ka波段宽带圆极化器的研制过程。该器件由90°两壁波纹移相器和改进型双脊波导形式的正交模式耦合器构成,工作频带为26.5-40 GHz,相对带宽达到41%。首先介绍了圆极化器的应用背景及工作原理,继而进行模型设计和仿真优化,最后进行结构设计和样品实测。实测结果显示,移相器的相移误差为90±4°,轴比达到0.6 dB,正交模式耦合器的交叉极化为-26 dB,隔离度为-35 dB,器件端口驻波均低于-18 dB,实测结果与设计仿真相符。

英文摘要：

Ka-band broadband receiver of Tianma telescope is an important observation platform for the study of star formation and deep space exploration. This paper discusses the development process of Ka-band wideband circular polarizer of the receiver core device. The device consists of 90° phase shifter and ortho-mode transducer （OMT）, whose operating frequency band is 26. 5-40GHz, and relative bandwidth reaches 41%. This paper firstly introduces the application background and working principle of circular polarizer, and then carries on the concrete model design and electromagnetic simulation with electromagnetic simulation software, then carries on the structural design and processing test. The results of final test indicate that phase error by the phase shifter is 90 ± 4° , axial ratio is 0. 6dB, cross polarization of OMT is -26dB, isolation of OMT is -35dB, return loss of each port is less than -18dB. These results are consistent with the design simulation.