低雷达散射截面的超薄宽带完美吸波屏设计研究

Design of ultrathin broadband perfect metamaterial absorber with low radar cross section

提出了一种基于PMA单元结构的超薄宽带完美吸波屏设计方法.该方法将多层拓展带宽的技术与单层多谐振方法有机结合,实现带宽拓展的同时,保持了完美吸波屏结构简单、无集总元件的特点,易于实际加工和应用.以双层三谐振超薄宽带完美吸波屏为例,结合其等效电路,理论上验证了所设计吸波屏的吸波机理,同时验证了方法的有效性.仿真分析该吸波屏具有低雷达散射截面、极化不敏感和宽入射角的特征.仿真和实测结果表明:该吸波屏在厚度为0.01λ的条件下,具有14.1%的半波功率带宽;-3dBsm的雷达散射截面缩减带宽为18.9%,在法线方向的最大缩减量为23 dBsm,在法向±40°内具有较好的雷达散射截面减缩效果.

We propose a method of designing ultrathin broadband perfect metamaterial absorber （PMA） which is based on the parameters of the cell. The bandwidth is enhanced via the method which combines the multilayer and multi-resonance in a layer. And it is not complex due to having no lumped elements in it, so it is easy to fabricate and apply. In order to illustrate the method, a double-layer perfect metamaterial absorber with three resonance peaks is designed using the above method. The equivalent circuit of the proposed absorber is analyzed so as to better understand the mechanism of the high absorption. By adjusting geometric parameters of the structure, we can obtain a polarization-insensitive and wide-incident-angle ultra-thin absorber. Simulated and experimental results show that the full-width at half-maximum is 14.1%when the thickness of the filer is only 0.01λ, and the bandwidth of？3 dBsm radar cross section reduction is 18.9%. At resonance, the reduction value may exceed 23 dBsm while the absorber has a good characteristic of RCS reduction at the boresight direction from？40°to＋40°.