Electro-Mechanically Tunable Low-Loss mm-Wave LP to LHCP or RHCP Conversion Metasurface

The design of a novel electro-mechanically tunable reflection polarization conversion metasurface at millimetre-wave frequencies is presented. Tunability is achieved via a variable air cavity between an anisotropic impedance surface and a ground plane. The air cavity height variation provides a polarization conversion from linear polarization to right-handed circular polarization or left-handed circular polarization. Simulations have been carried out using CST Microwave Studio to evaluate the proposed metasurface's reflection characteristics and tunability. Simulations demonstrate a controllable transition between the two circular polarization states at 76 GHz with extremely low reflection losses.