Dual-channel broadband polarization multiplexing and phase modulation metasurface in GHz band

This paper introduces a dual-channel polarization converter based on a metasurface operating in the GHz band. In channel 1 (9.5–13.5 GHz), the metasurface enables mutual conversion between horizontal and vertical linear polarizations and between right-handed circular polarization and left-handed circular polarization, achieving a polarization conversion ratio exceeding 90%. In channel 2, it supports mutual transformation between circular and linear polarizations. For linear-to-circular polarization conversion, the axial ratio remains below 3 dB in the range of 14.8–19.2 GHz and below 1 dB in the range of 15.5–18.6 GHz, indicating nearly ideal circular polarization. Moreover, for circular-to-linear polarization conversion, the polarization extinction ratio exceeds 20 dB across the 15.2–18.8 GHz range. Furthermore, by adopting a specially optimized inter-structure coupling design, the metasurface exhibits excellent Pancharatnam–Berry phase characteristics over the entire operating band. As the structure rotates, the phase intervals remain nearly uniform, while amplitude deviation is significantly reduced, leading to a notable improvement in the overall performance of the metasurface.