Bilayer reprogrammable graphene meta-atoms for THz wave reflection/absorption

In this paper, a novel design of a reflector/absorber based on bilayer reprogrammable graphene meta-atoms for terahertz frequencies, is presented. The proposed structure includes from circular graphene meta-atoms periodic array located on a metallic grounded SiO₂ substrate with stacking the double layer ring graphene metasurface. The performance of the design has been analyzed numerically. The graphene-based metasurface obtains more than 95% reflection in the operating frequency range from 0.1 to 4 THz with insensitivity to the incident angles and the polarization. Moreover, more than 93% absorption in the graphene-based metasurface is accomplished through electrically reconfiguring the metasurface response via the Fermi level of the graphene. It demonstrated that the graphene absorber remains as the single/dual bands for a wide range by a reprogrammable graphene-based meta-atoms. Furthermore, the proposed dual-band absorber is not sensitive to polarization and maintains its properties under various incident angles. The results reveal that the proposed THz metasurface is promising for intelligent and efficient THz wireless communications.