A high efficiency ultra-wideband circular-to-linear polarization conversion metasurface

In this work, an 8-shaped metasurface is proposed for circular-to-linear (CTL) polarization conversion, which is an orthotropic anisotropic structure composed of an array of 8-shaped metal patches printed on a grounded dielectric substrate and covered by a top dielectric layer. Because the 8-shaped metasurface has an appropriate anisotropy, which can make the reflection phase difference under u- and v-polarized incidences close to +90 degrees in an ultra-wide frequency range, it can be used as an ultra-wideband CTL polarization conversion metasurface. Numerical simulated results show that the 8-shaped metasurface can achieve high-efficiency ultra-wideband CTL polarization conversion, it can convert right-handed circular-polarized (RHCP) wave to a y-polarized one and convert left-handed circular-polarized (LHCP) wave to a x-polarized one in the ultra-wide frequency band from 8.34 to 26.06 GHz with a relative bandwidth of 103.0%, and the polarization conversion rate (PCR) can be kept larger than 99.6% in the total working band. Finally, an experimental verification is carried out, and a reasonable agreement is observed between the simulated and experimental results.