Graphene-based terahertz metamaterial absorber for broadband applications

Terahertz (THz) metamaterial absorbers are promised as one of the appropriate candidates for the biosensing and imaging novel devices. In this work, a wideband THz absorber consists of two periodic arrays of graphene ribbons (PAGRs) and one graphene continuous sheet (GCS) in a form of Fabry-Perot resonator is presented. Analytical circuit model of PAGRs and GCS in addition to a developed transmission line theory is exploited to model the proposed structure as RLC circuits. The concept of impedance matching with the aid of circuit principles besides a genetic algorithm (GA) are implemented to reduce the reflected waves from the structure. As a result, a THz absorber with absorption over 98% in the frequency range of 6.45-7.35 THz is achieved. The use of GCS as a coupling element to boost the absorption bandwidth is investigated. The results of this work is in a high demand for the THz sensing and imaging applications and it can be fabricated through chemical vapor deposition (CVD).