赋形双反射面天线口面场分布的优化

摘要

口面场分布函数是反射面天线赋形的主要参数之一，对反射面天线辐射性能起着决定性作用。针对采用分析方法确定口面场分布函数的缺陷，提出了一种优化口面场分布函数的方法。通过分析口面场分布函数与天线辐射场之间的关系，构造了基于遗传算法优化口面场分布函数的数学模型，并分别给出以天线效率和灵敏度为优化目标的2个优化实例。计算结果显示，在优化天线效率的实例中，在满足第一旁瓣电平低于－20 dB 的要求下，天线效率高于88％；在优化天线灵敏度的实例中，天线G／T值提高了0．2 dB／K以上的，所提方法达到了预期效果。%Aperture field distribution is a key parameter in reflector antenna shaping,having crucial effect on the antenna radiation performance.To mitigate the limitation of existed method in aperture field distribution optimization,an optimized aperture field optimiza⁃tion method is proposed. Based on the relationship between the aperture fieldand the radiation pattern, a new mathematical model is constructed,and a genetic algorithm is employed in the optimization.Two examples are presented ofoptimizing the antenna efficiency and the antenna sensitivity respectively.In the example of optimization for maximum antenna efficiency with constrained sidelobe level,the result achieves an aperture efficiency better than 88%,while the first sidelobe level is lower than the given -20 dB. In the example of the antenna sensitivityoptimization, the G/T valve is improved by more than 0. 2 dB/K. These two examples show that the proposed method achieves the expected effect.