A Reflection–Transmission Multifunctional Polarization Conversion Metasurface

In this paper, a multifunctional polarization conversion metasurface (MPCM) has been proposed that can switch between seven different transmissive and reflective polarization conversion modes. The basic unit cell consists of three layers of split square rings (SSR) separated by two substrates, and a PIN diode is embedded in the top SSR to dynamically control asymmetric transmission and reflection responses. The layer-by-layer design guideline is provided with the polarization conversion mechanism illustrated. A prototype made up of 20 × 20 units was fabricated and measured. The measurement and simulation results demonstrate the versatile polarization conversions including co-polarization reflection, cross-polarization transmission, and circular polarization reflection and transmission, depending on the incident x - and y -polarized waves forward and backward. Significantly, the performance of the MPCM keeps excellent in a large oblique angle range of 50°. The MPCM synthesized from the single SSR layers provides an idea for general transmissive and reflective metasurface design, which is expected to be applied in the fields of radar and wireless communications.