为实现远红外大气窗口（8～14 μm）的低红外透过率，基于六边形环状结构设计了双屏远红外频率选择表面（FSS）。仿真结果表明，该结构在8～14 μm 波段的平均透过率低于5%。对该结构的表面电流分析说明，谐振单元表面感应出的对称分布电流以及双屏结构之间的耦合效应使得散射场增强，透过率降低。研究了该结构在不同入射角和不同极化条件下的传输特性，结果表明该结构在8～14 μm 具有良好的角度稳定性和极化稳定性。分析了介质层介电常数、厚度以及损耗角正切对该FSS 传输特性的影响，结果表明介质层介电常数对FSS 的谐振频率和带宽有较大影响。

In order to get a low transmission rate in the far-infrared atmospheric window(8-14 μm), a double layer far-infrared frequency selective surface(FSS) based on a hexagonal loop structure is designed. Simulation results show that the average transmission is lower than 5% and within 8-14 μm. As per the surface current analysis of the periodic structure, the symmetrically inducted current of the resonant unit and the coupling effect between the double layer structure enhance the scattering field and decrease the transmission rate. In this paper, the transmission properties of the structures under different incident angles and polarizations are studied. The results show that the structure has good angle stability and polarization stability. The effect of the dielectric layer’s properties (thickness, dielectric constant, and loss tangent) on the transmission of FSS is analyzed. The results indicate that the dielectric constant significantly affects the resonant frequency and bandwidth of the structure.