一种抑制高功率微波击穿的副反射面天线罩设计

The design of sub-reflector radome for suppressing HPM air breakdown

针对应用于辐射高功率微波的双反射面天线系统设计了一种新型抑制高功率微波击穿的副反射面天线罩.该副反射面天线罩为基于复合材料的曲面球壳体结构,通过在罩内填充SF6气体,能够有效抑制副反射面附近高功率微波击穿.首先仿真分析了高功率脉冲照射下的天线副反射面附近区域空气击穿空间分布,确定天线罩的最小外廓尺寸.然后开展天线罩低损耗设计方法研究,通过采用优化算法对罩体外形曲线进行优化设计,使得电磁波与天线罩体的夹角控制在44°以内,并以此作为输入优化得到使透波系数最优的蒙皮和芯层厚度参数.此外,为避免复杂的成型工艺,将副面罩简化为泡沫环筋结构,其既有低损耗特性又兼顾了一定结构强度.最后对天线罩的电气性能进行仿真与测试验证,实测结果表明这种副面罩引入的插入损耗在0.3dB以内,透波率达93.4%以上,对反射面天线系统的辐射性能影响很小.

This paper presents a novel design of sub-reflctor radome for suppressing high power microwave(HPM)air breakdown in the HPM propagation of dual reflector antenna system.The sub-reflector radome based on composite material is an ellipsoid spherical shell filled with SF6 gas to increase air breakdown threshold.Firstly,the minimum outline of radome is obtained by calculating air breakdown region near sub-reflector with high power excitation.Then low-loss design method has been investigated,for one thing,the outline curve is optimized by using particle swarm algorithm to keep the angle between electromagnetic wave and the radome normal line less than 44 degree,and for another thing,thickness parameters of three layers are optimized to get maximum transmission coefficient.Furthermore,in order to prevent the difficulty of molding process,the radome is simplified as reinforced PMI hoop structure,which has low insert loss as well as good mechanical performance.Finally,the sub-reflector radome is fabricated and measured,the measurement results show the insert loss is less than 0.3 dB and the microwave transmittance is up to 93.4%,which means it affects the radiation performance little.