螺旋环超材料太赫兹吸波器的响应原理及特性

摘要

提出一种表层电磁谐振器呈螺旋环的超材料太赫兹吸波器.与常规的超材料吸波器不同,在材料的种类及厚度都不变的情况下,仅通过改变表面螺旋环的环数或环的起始和终止位置,就能有效地调节螺旋环超材料的太赫兹响应性能.研究发现,该超材料的响应频率的仿真值与驻波理论计算值基本吻合,说明螺旋环超材料的响应机理可以通过驻波理论解释、其响应频率具有可预计性.为了探究螺旋环超材料的响应机理,还比较研究了闭合圆环及开口圆环超材料吸波器的性能.结果表明,螺旋环、闭合圆环、开口圆环三种超材料吸波器具有部分类似的太赫兹响应性能.但是,与另外两种超材料不同,螺旋环超材料的表层电磁谐振器是半径连续变化的螺旋环、具有更强的耦合作用以及更加简便和灵活的性能调节方式.研究成果对超材料的理论及设计研究有新的启示.%Novel spiral-shaped metamaterial absorbers (MAs) were designed.Different from the traditional MAs,the THz responses of the as-designed MAs can be effectively adjusted by altering the number of the spirals and their locations,in which the functional materials and their thicknesses remain un-changed.Results reveal that the response frequencies obtained by CST simulations agree well with those theoretically estimated by standing wave formula,suggesting high predictability of the response frequency for such MAs.In order to better understand the response mechanism of the spiral-shaped MAs,ring-shaped and split ring-shaped MAs were simultaneously investigated.Simulation results indicate that these MAs exhibit some similar response properties.However,different from the ring-shaped and split ring-shaped MAs,the as-designed spiral-shaped MAs exhibit stronger coupling effect and easier adjustment,largely due to the continuous alteration in the spiral radius for the latter.These results are helpful for promoting the theoretical study and design of metamaterials.