Broadband and high-efficient reflective linear–circular polarization convertor based on three-dimensional all-metal anisotropic metamaterial at terahertz frequencies

Abstract

In this paper, we proposed a broadband and high-efficient reflective linear–circular​ polarization convertor (LCPC) based on three-dimensional (3D) all-metal anisotropic metamaterial (AMM) in terahertz (THz) region. The LCPC unit-cell is composed of the stand-up inverted U-shaped resonator (USR) deposited on a ground plane. This LCPC design can convert both incident x- and y-polarized (y-pol) waves from linear to circular polarization after reflection in a broadband frequency range of 1.98-4.12THz with an axial ratio (AR) below 3 dB and polarization conversion efficiency (PCE) over 98% on average. The numerical simulation results show that the broadband polarization conversion of the designed LCPC is caused by the overlaps of stronger electric and magnetic dipolar coupling resonances. The polarization conversion properties of the designed LCPC can be adjusted by varying the geometric parameters of the USR. The proposed LCPC design has potential applications in many areas such as spectroscopy, detection, imaging, and communications in the THz region.