Simultaneous transmissive and reflective polarization conversion cross different operating bands in a single metasurface

This paper proposes a bifunctional linear-to linear polarization converter with a sandwich structure that enables transmissive and reflective polarization conversions in different operating bands, simultaneously. The unit cell of the converter metasurface comprises an S-shaped wire, a dielectric slab, and an S-shaped slot, where the S-shaped wire and slot have complementary structures and a 30° difference in orientation. When an x-polarized electromagnetic wave is incident on the proposed metasurface, most of the transmitted wave is y-polarized in the frequency range of 7.07 GHz to 7.46 GHz, while most of the reflected wave is y-polarized in the frequency range of 16.59 GHz to 16.91 GHz. The physical mechanism underlying these two types of polarization conversions was analyzed based on the surface current, and electric field distributions. Notably, the transmissive polarization conversion was primarily attributed to magnetic resonance, while its reflective counterpart was ascribed to electric resonance. In addition, the Jones vector and Stokes parameters were analyzed thereby elucidating the polarization characteristics of the proposed metasurface. Furthermore, simulation data demonstrated excellent agreement with the measured results of polarization conversion. The designed metasurface will promote subsequent research on bifunctional polarization converters.