Tunable ultrathin ultrabroadband metamaterial absorber with graphene-stack-based structure at lower terahertz frequency

摘要

In this paper, we investigate the absorption characteristic of the graphene-stack-based metamaterial absorber at the lower terahertz frequency range for the ultrathin and ultrabroadband. The absorption spectrum can be dynamically controlled by changing the gate voltage on the graphene-stack cavity. The thickness of a designed structure is only lambda(0)/25.5 with respect to the center frequency. The absorption principle is discussed by modeling equivalent circuit and studying the distribution of electric field and surface currents. The simulated results show that the high absorption above 0.9 in the frequency range of 1.24 THz similar to 2.08 THz can be obtained. The absorption performance is insensitive to different incidence angles. The research results have great application potentials in the design of the terahertz device.