Dual-beam scanning using graphene-based reflectarray

A reflectarray possessing symmetrically dual-beam scanning capability is proposed, which is based on graphene reflective cells operating at Terahertz (THz). Due to the tunability of graphene´s conductivity, the phase distribution of the reflectarray can be controlled and then the electromagnetic properties of the surface can be altered. For simplicity, the reflectarray is composed of two types of cells with different phase responses, 0 and pi, which correspond to two different chemical potentials that can be obtained by applying different biased voltages. By designing the sequence of cells, the beam can be steered and the direction can be scanned in a range via switching between different phase distributions of the reflectarray. Simulation results and theoretical calculations agree well, demonstrating the possibility of beam scanning using graphene based reflectarray. This new electronically beam scanning mechanism offer an alternative to a conventional phased array.