利用石墨烯与金属相结合的方法提出了一种新型超材料吸波体结构,通过改变外加偏置电压来改变石墨烯的费米能级,在微波段分别实现了单频和宽频的振幅可调性,并阐述了其电磁吸波及振幅可调的机理。对单一频段下的超材料结构进行了模拟仿真,结果表明,当结构参数不变时,吸波体的吸收强度随石墨烯费米能级的增加而不断减小,最大调制深度达到了58.6%。当石墨烯费米能级为0 eV时,吸波体的中心频率随结构参数的改变而改变。基于多吸收峰叠加扩展带宽的原理,利用不同尺寸单元的排列实现了宽频吸波的特性,并通过仿真模拟证明了该宽频吸波体具有振幅可调的性质。

A novel metamaterial absorber based on a graphene-metal hybrid structure is proposed. The amplitude tunability at single frequency and broadband frequency within the microwave domain is realized via the change of graphene Fermi level by altering the applied voltage. The mechanisms of absorption and amplitude tunability of electromagnetic field are illustrated. The numerical simulation of this metamaterial structure under single frequency band is made. The results show that, when the structural parameters are fixed, the absorption intensity of absorber decreases with the increase of graphene Femi level and the maximum modulation depth reaches 58.6%. When the graphene Fermi level is 0 eV, the center frequency changes with the structural parameters. An array composed of unit structures with different sizes is used to realize the characteristic of the broadband wave absorption based on the multi-absorption-peak superimposed expansion bandwidth principle. The property of amplitude tunability possessed by this broadband absorber is confirmed by numerical simulations.