小型宽波束圆极化天线及馈电网络

Compact wide-beam circular polarization antenna and feed network

提出一种新型的小型宽波束圆极化天线及馈电网络。天线由四个独立辐射单元顺次旋转90°组合而成,辐射单元采用平面印刷电路工艺加工、使用容性加载及短路点调配方式实现小型化;使用变形的分支线定向耦合器与移相电路组合,实现具有功率分配与正交移相功能的馈电网络。经理论分析、软件仿真及实测表明:天线高度小于0.12λ,3dB波束宽度大于120°,6dB轴比波束宽度大于180°,辐射特性在15%相对带宽内稳定;天线的驻波比(VSWR)小于2.0的相对带宽为16%。该小型宽波束圆极化天线采用印刷电路工艺制作,结构紧凑,加工成本低、精度高,易于与微波电路集成,其结构也适用于S波段以上更高频段。

A kind of novel compact wide-beam circular polarization antenna and its feed network are presented. The antenna is composed of four independent radiation units which rotate 90° about the center separately. The miniaturization of the anten- na is realized by distributed capacitive load and short point. The feed network is composed of directional coupler and microstrip lines to achieve power division and quartered phase shift. The analysis, simulation and measured results indicate that the antenna＇s height is less than 0.12λ, the antenna＇s beam width is greater than 120°,the beam width of axial ratio less than 6dB is greater than 180°,and the char- acters mentioned above can be obtained in the frequency range over 15° band width,the relative band width of VSWR〈2.0 is 16%. The antenna is fabricated by PCB technics and could be integrated to microwave circuit conveniently. The fabri- cation has low cost and high precision. The structure could also be applied to fre- quency range higher than S band and has broad prospects of application.