基于液晶材料的超宽带可调带阻型频率选择表面

Ultra-wideband Tunable Band Stop Frequency Selective Surface Based on Liquid Crystal Material

本文采用圆环槽型结构设计了一款带阻型中心频率可调谐频率选择表面。以该单元结构为基础,采用了对称双屏级联的形式使用空气介质将单元进行前后级联,实现频率选择表面阻带带宽的宽带化设计。仿真结果表明,该频率选择表面-10dB带宽为5.1GHz,相对带宽为26.2%,相比于未采用级联形式的单元,其相对带宽有了显著的提高,同时其带内响应曲线也更加平稳。通过对液晶层施加偏置电压,调谐液晶材料的介电常数由2至3变化时,阻带的中心频率可获得1.3GHz的调谐量,实现了频率选择表面的可调谐特性。

In this paper,a band-stop type center frequency tunable frequency selective surface is designed with a circular groove structure.Based on the unit structure,a symmetrical double-screen cascade is used to cascade the units back and forth using air media to achieve a broadband design of FSS stopband bandwidth.The simulation results show that the FSS has a-10 d B bandwidth of 5.1 GHz and a relative bandwidth of 26.2%.Compared with the unit without cascade,the relative bandwidth has been significantly improved,and the in-band response curve is also more stable.By applying a bias voltage to the liquid crystal layer,when the dielectric constant of the tuned liquid crystal material changes from 2 to 3,the center frequency of the stop band can obtain a tuning amount of 1.3 GHz,realize the tunable characteristics of the frequency selective surface.