Broadband Linear-to-Circular Polarization Conversion Realized by the Solid State Plasma Metasurface

Abstract

In this paper, a solid-state plasma metasurface (SSPM) for linear-to-circular polarization conversion is designed and investigated. The unit cell of such a SSPM consists of three layers from bottom to top, which are the copper coating, the dielectric layer, and the solid-state plasma resonators, respectively. By exciting solid-state plasma resonance units in different regions, we successfully achieved two operating modes (modes I and II). In mode I, the axial ratio band which is less than 3 dB (3 dB AR band) is mainly obtained in 14.34–19.61 GHz (the relative bandwidth is 31.25%). When the proposed SSPM is regulated to mode II, the 3 dB AR band is changed to 8.81–14.34 GHz (the relative bandwidth is 40.90%). The polarization conversion rate, phase difference, AR curves, and surface current diagrams are analyzed to explore the performances of the proposed SSPM. Our design promotes the potential applications of tunable devices.