Optically transparent, broadband and omnidirectional microwave absorber based on graphene-SiO metasurfaces.

Broadband and omnidirectional absorption of electromagnetic waves is required in various technologies, such as stealth, high quality wireless communications, spacecraft shielding. In this study, we theoretically and numerically study a graphene-based absorber achieving broadband and omnidirectional absorption from 4 GHz to 100 GHz and 0 to 50 ∼70 , with over 90% absorption efficiency. By applying a thin layer of graphene upon a SiO moth-eye structure, we show that electromagnetic waves can be effectively absorbed in the graphene layer and that the structure is optically transparent, ideal for civilian and military applications.