Broadband Terahertz Linear-to-Circular Polarization Converter based on Metasurface

Effective manipulation of polarization of electromagnetic (EM) waves has drawn a lot of research interests in many fields, such as the terahertz (THz) technology. In this paper, a broadband linear-to-circular (LTC) polarization converter based on metasurface is proposed in THz frequency. The proposed converter consists of periodic unit cells which are formed by patterned metal strips, a dielectric layer, and a fully reflective gold mirror. In the frequency range of 0.536-1.270THz, the converter can convert linear polarization wave into circular polarization wave with the axis ratio less than 3dB. The simulated results indicate that the relative bandwidth reaches 81.28% and the efficiency is higher than 74%, thus, the broadband LTC polarization conversion has been realized.