Abstract
A single-layer metasurface polarization converter is proposed to integrate multi-band and multi-polarization conversion in two mechanically selectable scattering states. Its unit cell consists of a split-ring resonator with an embedded rectangular patch and a detachable continuous metallic backing plate. Attaching the backing plate suppresses transmission and enables reflection-only operation, whereas removing it produces simultaneous reflection and transmission. Using the same patterned metasurface, the proposed converter achieves multi-band linear-to-orthogonal-linear and linear-to-circular polarization conversion in reflection, as well as dual-band linear-to-circular conversion in transmission. This multifunctional operation requires neither active components nor biasing networks. Surface current distributions and an equivalent circuit model are employed to explain the conversion mechanisms. A prototype comprising 35 × 35 unit cells was fabricated and measured. The measured polarization conversion ratio exceeds 0.9 in three reflection bands, while the measured axial ratio remains below 3 dB in three reflection bands and two transmission bands, in good agreement with the simulations. These results demonstrate a compact and structurally simple solution for multifunctional polarization control in wireless communication and radar systems.