Linear-to-Circular Polarization Converter with Adjustable Bandwidth Realized by the Graphene Transmissive Metasurface

A tunable linear-to-circular polarization converter (LTCPC) for the terahertz (THz) regime which consists of two conductive layers and a graphene transmissive metasurface layer separated by dielectric is reported in this work. The equivalent surface resistance modeling method adopted to investigate peculiar electronic properties graphene. simulation results show that when Fermi energy (Ef) 1.1 eV, linearly-polarized wave can be transformed into circularly-polarized working band ranging from 0.9498 1.3827 THz (the relative bandwidth 37.1%) with axial ratio (AR) less than 3 dB. Moreover, regulated desired one varying level via bias voltage rather manually modifying structure. We have analyzed mechanism conversion, especially, magnitudes phase difference cross- co-polarization transmission coefficients, AR curves, current diagrams at y-polarized incidence. Our findings open up promising possibilities towards realization controllable devices modulation, has advantages adjustability over traditional devices.