基于树枝结构单元的超材料宽带微波吸收器

本文设计并制作了一种基于树枝结构单元的超材料宽带微波吸收器.该超材料吸收器采用夹层结构，由按六边形密集排布的金属树枝阵列、双层介质基板和金属薄膜组成.通过调节树枝单元的几何参数和金属树枝阵列的排布方式，可以出现三个吸收峰，实现三频工作.通过调节三个吸收峰工作的频率形成宽频吸收，采用夹层结构提高吸收效率，从而对垂直入射到超材料表面的微波实现高吸收.实验表明吸收器的反射曲线从9.79 GHz到11.72 GHz出现了反射率小于10%的较宽吸收带，透射曲线恒等于0，吸收率大于90%的带宽为1.93 GHz.这种 关键词： 树枝状结构 夹层结构 吸收效率 吸收带宽

Broadband metamaterial absorber based on dendritic structure

We present a metamaterial absorber (MA) composed of double layers of metal dendritic cells,dielectric substrate and metal film.With three different sizes of dendritic cells arranging in hexagonal array,it is able to find three discrete absorption peaks.Our experiments confirm that,if the frequencies of the three absorption peaks go closer,a combined broadband absorption peak could be achieved.Compared with the metamaterial absorber with only one singer layer of metal dendritic cells,the double-layered metal dendritic cells adopted in our MA greatly improve the absorption efficiency.The experimental result shows an absorption band of 1.93 GHz width with the absorptivity higher than 90% in the frequency range between 9.79 and 11.72 GHz.The proposed MA has a series of advantages such as high absorptivity,simple structure,small thickness,2D isotropy and wide absorption band.