全角度稳定的多频带高性能FSS天线罩研究

Research on Multi-band High Performance FSS Radome Insensitive to All Incident Angles

为解决通信系统天线罩的角度敏感问题,提出了一种新型超小型化、多频带、全角全极化稳定的强耦合型频率选择表面(SC-FSS)设计方法,通过引入两种层间强耦合谐振结构,先后研制了高选择性双阻带、双通带型SCFSS天线罩,其单元尺寸小于0.03λ。研究了不同工作模式下SC-FSS的电场和表面电流分布,建立了相应的等效电路模型,提取计算了精准的等效电路参数,解释了SC-FSS结构的物理机理。加工制作的双通带天线罩样品测试结果表明,天线罩的两个通带分别在2 GHz和5.8 GHz,并分别有一个4 GHz的低阻带和7.5 GHz的高阻带。特别值得一提的是,无论对于TE模式还是TM模式波,即使入射角度增至86°,所有传输极点和传输零点保持不变,与理论计算和全波仿真结果高度吻合。因此,所提出的多频段、超小型化SC-FSS结构几乎对所有入射波角度和极化都不敏感,可用于高性能天线罩、天线反射器和电磁干扰屏蔽设计中。

In order to solve the angle-sensitivity problem of communication system radome,a novel design method of ultra-miniaturized strong coupled frequency selective surface(SC-FSS)with all-angle-insensitive and all-polarization-insensitive multi-band is proposed by introducing the different interlayer coupling patches.High selectivity dual-stopband and dual-passband SC-FSS radomes are developed successively with unit cell less than 0.03λ.Furthermore,to explain the physical mechanism and formulate relevant design equations,the corresponding equivalent circuit models are established by analyzing the distribution of the electric field and surface current under different working modes of SC-FSS structure.Finally,a prototype of the proposed dualpassband structure is fabricated and measured.The experiment results show that there are a lower passband working at 2 GHz and a higher passband at 5.8 GHz with a lower stopband at 4 GHz and a higher at 7.5 GHz on the ends of above passbands respectively.It is particularly worth mentioning that for both TE and TM modes,all transmission poles and transmission zeros remain unchanged even if the incident angle increases to 86°,which is highly consistent with the results of theoretical calculation and full-wave simulation.Therefore,the proposed ultra-miniaturized multi-band SC-FSS structure is insensitive to almost all incident angles and polarizations,which can be applied to design the high-performance radome,antenna reflector and electromagnetic interference shielding.