A Switchable Polarization Convertor based on Active Metasurface using Varactor Diode

In this paper, a switchable polarization convertor based on active frequency selective surface (AFSS) has been designed. The AFSS is composed of two rotated back-to-back C-shaped patches with two varactors loaded in the gap. The varactor diode is fed by coplanar parallel connection. The patches and metallic ground are separated by a 4 mm height air layer. The linear incident wave can be converted into cross-polarization under high voltage excitation from 5.3 GHz to 17.9 GHz. The linear incident wave can be converted into circular polarization from 4.9 GHz to 13.6 GHz without voltage biasing.