椭圆极化前馈抛物面天线的焦场分析

Focal field analysis for elliptically polarized front-fed reflector antenna

在大型反射面天线中,研究焦面场的分布对于合理设计与配置馈源或馈源阵列具有指导意义。采用物理光学法,推导了平面入射波为椭圆极化、斜入射时,前馈抛物面天线的焦平面、及与焦面平行的平面上的电场计算公式。并以我国计划建造的500 m口径球面反射天文望远镜(FAST)为实例,计算了其焦面场并得到结论:入射波的极化方式主要影响焦场的极化,而对场强分布影响不大。

For large reflector antenna, it is very important to analyze the focal field which is applied to design and derive suitable excitation for the feed or array feeds. The field on the focal plane and the planes parallel to focal plane of a front-fed symmetrical parabolic reflector is analyzed by PO method when the incoming plane wave is elliptic-polarization and off-axis. Combining the FAST （five-hundred-meter-aperture-spherical-telescope） project which will be built in China, the field distribution is computed and useful conclusion is deserved. That is the incoming wave＇s polarization character mainly influences the focal field polarization and almost has no effect on the field distribution.