A novel tunable triple-band terahertz absorber with five graphene discs in one unit cell

A high tunable terahertz graphene-based absorber which can operate in three band is presented. A patterned sheet with an array of graphene nano-disc can enhance absorption at the single resonance frequency. By insertion of five graphene discs in one unit cell, the performance of this absorber is improved. The five nano-discs have designed with different sizes for achieving multi-band operation. The effects of the radius and distance between the discs are studied. Good absorption, compact size and operation at the THz band are the major advantages of the introduced structure. Also the tunability is more than the state in which graphene based nano-disc, nano-ribbon, nanoring or cross-shaped is utilized.