径向双层介质加载圆波导的TE_(11)-HE_(11)模式转换天线

Circular waveguide TE_(11)-HE_(11) mode transducing antenna loaded with radial double mediums

介绍了径向双层介质加载圆波导的TE_(11)-HE_(11)模式转换天线的设计原理、实验方法及结果。该模式转换天线由圆波导TE_(11)-HE_(11)模式转换器和辐射器组成:圆波导TE_(11)-HE_(11)模式转换器是在圆波导内沿径向加载两种不同介电常数的微波介质来完成模式转换,辐射器采用开口圆波导或小张角圆锥喇叭将HE_(11)模辐射出去。应用HFSS软件对设计的两种模式转换天线进行模拟优化,数值结果显示这两种天线在线极化和圆极化工作状态下其E面、H面辐射方向图在一定波瓣宽度内均具有较高的等化特性及低副瓣电平。应用矢量网络分析仪和频谱分析仪对线极化TE11模激励状态下的两种模式转换天线的增益和驻波系数进行测试,测试结果表明:在中心频率9.4GHz频点辐射器采用开口圆波导或小张角圆锥喇叭时天线增益分别为11.21dB和15.58dB,且驻波系数均小于1.05。实测结果与仿真结果基本一致,证明了该模式转换天线技术的可行性与正确性。

A circular waveguide TE11-HEu mode transducing antenna loaded with radial double mediums is reported basedon measurements and simulations. The mode transducing antenna includes a novel broadband circular waveguide TEll-HE11 modeconverter and a radiator. The circular waveguide TEn-HEn mode converter is inserted with radial double mediums, and the radi-ator adopting an open circular waveguide or a small angle conical horn will radiate out HEn mode. Using the commercial softwareHFSS to simulate and optimize two kinds of circular waveguide TEll-HE^I mode transducing antennas, the numerical results showthat the two antennas have a highly symmetrical radiation pattern and a relatively low sidelobe level, no matter they work at linearpolarization or circular polarization. The standing wave ratio （VSWR） and the gain of the two kinds of mode transducing antennasare tested by using the vector network analyzer and the spectrum analyzer. The measured results reveal that the gain ofthe anten-na which uses an open-ended circular waveguide as the radiator is 11.21 dB, the gain of the antenna which uses a small angle coni-cal horn as the radiator is 15.58 dB, and the VSWR is less than 1.05 at the center frequency of 9.4 GHz. The experimental re-sults are in agreement with the simulation results, which validates the feasibility and correctness of the antenna technology of themode conversion.