In view of the increasingly important radar antenna frequency selection surface (FSS) on military equipment,the characteristics of the FSS radar cross section (RCS) area and the difference from the metal surface RCS are analyzed,and the internal mechanism of this difference is clarified,which provides the theory guidance and solution for the improvement of the FSS radome and the similar cavity RCS Method.Firstly,the generation mechanism of the radar cavity RCS covering the frequency selection surface is theoretically analyzed,and then the data of different radar cavity RCS are calculated with the full wave rigorous simulation algorithm,and the theoretical analysis conclusion of the front is authenticated with the internal field map.The theoretical and simulation analysis shows that the high reflection characteristics outside FSS are not fully reflecting electromagnetic signal as the metal surface.The transmission of the radome and the electromagnetic wave energy accumulation and the two radiation caused by the cavity effect in the mask must be considered.These factors have great influence on the RCS of the frequency selective radar cavity.Finally,a method of reducing cavity resonance effect and energy converging to improve the frequency selection mask RCS is proposed,and the method makes the improvement of RCS up to 10 dB in most frequency bands,which has achieved good results.%针对在军工装备上日益重要的雷达天线频率选择表面(frequency selective surface,FSS),分析了FSS雷达散射截面积(radar cross-section,RCS)的特征,以及和金属表面RCS的区别,并澄清了产生这种差异的内部机理,为改善FSS天线罩以及类似腔体的RCS提供了理论指导和解决问题的思路和方法.首先从理论上分析了覆盖频选表面的雷达腔RCS的产生机理,然后用全波严格仿真算法计算了不同雷达腔RCS的数据,并结合内部场图认证了前面的理论分析结论.理论和仿真分析表明,频选带外的高反射特性并非像金属表面那样完全反射电磁信号,必须考虑频选天线罩的透射和罩内的腔体效应导致的电磁波能量聚集和二次辐射,这些因素对覆盖频选雷达腔体的RCS产生很大的影响.最后,提出了一种利用吸波材料减少腔体谐振效应和能量汇聚从而改善频选罩RCS的方法,取得了良好的效果,在大部分频段,该方法使RCS改善达10 dB以上.
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