Design And Analysis Of A Broadband Graphene Metasurface Based Tunable Linear To Circular Polarization Converter In Terahertz Band

Metasurface based polarization converters with tunable frequency response in terahertz (THz) band are expected to be a key component in future wireless systems. In this work, we present the design of a novel and tunable broadband linear-to-circular polarization converter operating in the THz band using a graphene based metasurface. Our proposed structure is composed of a SiO2 substrate sandwiched between a slotted top graphene and a bottom gold layer. It has a compact unit-cell (lambda/7), thin configuration (lambda/10) and a tunable operating bandwidth which can be increased up to 850 GHz by tuning the chemical potential, mu of graphene. Moreover, it gives stable broadband performance for up to 40 degrees incident angle of the input wave. The proposed structure is simulated using finite element method and its response is validated using an equivalent circuit model approach.