基于单层频率选择表面的轻质宽频吸波体设计

Design of lightweight broadband absorber based on single-layer frequency selective surface

为解决现有的微波吸波体不能同时具有低面密度和高吸收率的问题,提出了一种电阻式闵可夫斯基环频率选择结构(RMLFSS)。RMLFSS整体厚度为6.6 mm,面密度不超过0.678 kg/m^(2)。RMLFSS有三层,分别是电阻频率选择表面(RFSS)、PMI泡沫板和金属地面。RFSS由打印在PI薄膜上的闵可夫斯基环阵列构成,每个单元上加载8个贴片电阻。仿真结果表明正入射下,在4.7~16.75 GHz范围内,RMLFSS的反射系数小于-10 dB,分数带宽为112.4%,对应90%的吸收率,在5.8~15.95 GHz范围内,反射系数小于-15 dB,吸收率为96.8%。实测结果与仿真结果吻合较好,验证了设计的有效性。

The existing microwave absorbers could not possess the characteristics of low surface density and high absorptivity simultaneously.This work provided a resistive Minkowski loops frequency selective structure(RMLFSS)to solve this problem.The thickness of RMLFSS is 6.6 mm and the surface density is less than 0.678 kg/m^(2).RMLFSS consists of three layers,which are resistive frequency selective surface(RFSS),PMI foam slab and metal ground.RFSS is constructed by printing Minkowski loops array on PI film,which is loaded with eight chip resistors on each unit.Simulation results indicate that at normal incidence,the reflection coefficient of RMLFSS is less than-10 dB from 4.7 GHz to 16.75 GHz,and the fractional bandwidth is 112.4%,corresponding to 90%absorptivity.Furthermore,the reflection coefficient is less than-15 dB from 5.8 GHz to 15.95 GHz,and the absorptivity of which is 96.8%.The good agreement between the measurements and simulation results verified the effectiveness of the design.