宽角扫描双反射面天线的方向图分析

Pattern analysis of dual-reflector antennas under wide-angle scanning

为了计算双反射面天线的宽角扫描辐射特性,该文给出了一种双反射面天线的方向图混合分析方法.先将几何光学和基于傅里叶 贝塞尔方法的物理光学相结合,提出了一种有效的双反射面天线次级方向图分析方法.与文献中已有结果的比较表明,文中的混合方法是可行和精确的,并采用该混合方法对一个侧馈偏置卡塞格伦天线进行了分析,给出了该天线的宽角扫描辐射特性和增益.计算结果表明,该天线在宽角扫描过程中,辐射方向图无太大畸变,增益损失很小,副瓣电平优于-20dB.

In order to calculate the wide-angle scanning characteristics of the dual reflector antenna, a hybrid pattern analysis method for the antenna is presented. We combine the geometrical optics (GO) with the physical optics (PO) based on the Fourier-Bessel technique, and propose an effective hybrid secondary pattern analysis method. The simulated analysis results of the hybrid method are in good agreement with the results presented in the literature, which shows that the method is feasible and accurate. Finally, the hybrid method is used to analyze a side-fed offset Cassegrain (SFOC) antenna, and its radiation characteristics as well as its gain under wide-angle scanning are given. The calculated results show that the radiation patterns of the SFOC antenna have less distortion, its gain losses are small, and its sidelobe levels are better than-20 dB in the wide-angle scanning region.