结构无序化对吸波超材料性能的影响

Influence of Disorder on the Absorption Properties of Metamaterial Absorbers

近年来,超材料由于其独特的电磁响应特性得到了世界各国研究者的关注,并得到了广泛的应用,其中,用于电磁波吸收是研究重点之一。通常情况下超材料由结构单元按照周期排列构成,然而最近无序结构超材料引起了研究者的关注,因为它们表现出了一些比传统周期结构超材料更加优异的性能。为此,系统研究了关键结构参数无序化对短切线吸波超材料性能的影响。结果表明,短切线长度的无序化可拓展吸波带宽,为宽带吸波材料的设计提供了一种思路,空间取向的无序化可使得短切线吸波超材料电磁特性由单极化响应向任意极化响应转变,而空间位置的无序化则对吸波性能的影响可忽略不计,在微波频段进行了数值仿真和实验测试的验证,并分析与讨论了无序吸波超材料在工程领域的应用前景。提出的方法对其他结构以及频段的吸波超材料也有重要的参考。

Metamaterials have attracted considerable attentions due to their electromagnetic response properties and po- tential applications. One important sdudy of metamaterials is electromagnetic wave absorbers. For convenience of the fabrication, most current metamaterials are realized as periodic arrays. However, random metamaterials have gained a growing interest recently, because they exhibit some more desirable electromagnetic properties. Therefore, the influences of disorder on the absorption properties of wire-based metamaterial absorbers were studies here. The numerical and experimental results show that the absorption bandwidth can be enhanced by disordering the wire length, providing a valuable method for designing the wideband absorbers. The absorbers allow a transformation from the absorption of only one linear polarization to that of all polarizations by introducing the disorder degree of the wire spatial orientation, but the random spatial position of wires has little effect on the absorption property. The potential application in the field of engineering was also discussed finally. It is expected that the proposed method can be used in the design of metamaterial absorbers consisting of other resonators and of other frequency bands.