一种新型红外频率选择表面

A Novel Infrared Frequency Selective Surface

为实现在中、远红外两个大气窗口的低透过率,设计了一种基于六边形环状结构的双屏红外频率选择表面,利用CST电磁软件进行仿真分析,发现该频率选择表面在3～5?m和8～15?m两个波段内的平均透过率低于0.025,实现了红外波段的双阻带;采用等效表面阻抗和表面电流法分析了该频率选择表面的滤波机理,发现不同极值点处由于屏间耦合或屏内单元间的耦合在谐振单元表面感应出对称分布的电流从而使散射总场增强,形成增强型反射,即比较理想的红外光阻带;最后研究了电磁波的入射角度、极化方式以及介质层的厚度对频率选择表面传输特性的影响。

In order to get low transmittance in both the mid-infrared and far-infrared atmospheric windows,a novel double-screen infrared frequency selective surface based on the hexagonal ring structure was designed.Simulation analysis using CST electromagnetic software showed that the average transmittance of the frequency selective surface in the two atmospheric windows(3-5μm and 8-15μm)for normal incidence waves is suppressed under 0.025,so that the dual stop-band of the infrared waveband was realized.Next,this paper researched the filtering mechanism of the frequency selective surface based on the effective surface impedance and the surface current.From this,it can be easily found that due to the coupling between screens or coupling between units in a screen,symmetrical distribution of the induced current enhances the total scattering filed,thus forming the enhanced reflection,namely the ideal infrared stop-bands.This paper analyzes the effect of electromagnetic wave incident angle,polarization mode,and the thickness of dielectric layer on the transmission properties of the frequency selective surface.