覆盖L波段的宽带隐身雷达天线罩设计

Design of Broadband Stealth Radome Covering L-band

设计了一款极化和角度不敏感的宽带频选吸波体,在X波段实现了宽带透射窗口以及包含L波段在内的宽频带吸收。该频选吸波体采用频率选择表面与电磁超材料吸波体相结合的方式,通过级联加载多层耦合型频率选择表面和双层高阻表面完成总体结构设计。理论上,利用等效电路法对多层耦合型频率选择表面及整体结构展开分析,论证频选结构和频选吸波体的谐振机理。数值仿真结果显示,该频选吸波体可以实现8.1～11.7 GHz频段内的宽频带透射,以及1.18～4 GHz、15～18 GHz频段内的宽频带吸收,其中透射窗口的插入损耗不大于3 dB。将该频选吸波体作为平面雷达天线罩与微带天线相结合,分析天线的辐射性能和散射特性。研究结果显示,天线在工作频带内保持了良好的辐射性能,而在带外实现了RCS的有效缩减,达到了天线系统的隐身目的。

A broadband frequency selective rasorber(FSR)with polarization and angle insensitivity is designed,which can realize a transmission window at X-band and the broadband stealth including the L-band.The FSR adopts a combination of a frequency selective surface(FSS)and an EM metamaterial absorber.The overall structure is accomplished by cascade loading of a multi-layer coupled FSS and a two-layer high resistance surface.In theory,the equivalent circuit method is used to analyze the multi-layer coupled FSS and the whole structure,while the resonance mechanism of the FSS and FSR is demonstrated.The numerical simulation results show that the FSR can achieve a broadband transmission in the frequency range of 8.1~11.7 GHz and wide band absorption in the range of 1.18~4 GHz and 15~18 GHz,wherein the insertion loss of the transmission window is greater than-3 dB.As a planar radar radome,the proposed FSR can be combined with a microstrip antenna to analyze the radiation performance and scattering characteristics of the whole system.Numerical simulation results show that the antenna maintains good radiation performance in the working frequency band,the effective reduction of RCS is realized outside the band,and it achieves the stealth purpose of the antenna system.