Polarization-Multiplexed Transmissive Metasurfaces for Multifunctional Focusing at 5.8 GHz

Metasurfaces, as subwavelength planar structures, offer unprecedented electromagnetic wavefront manipulation capabilities. However, most existing focusing metasurfaces operate in a single polarization mode, support only one focusing function, or rely on complex multi-unit configurations, limiting their versatility in practical applications. This study proposes a dual-polarization multiplexed transmissive focusing metasurface operating at 5.8 GHz. Through theoretical analysis and full-wave simulations, the electromagnetic response of the metasurface unit is systematically investigated. To overcome the limitations of conventional transmissive units, an anisotropic low-profile unit is designed using a hybrid stacking strategy that combines dielectric substrates and an air layer, achieving a compact profile of only 0.16λ. This unit achieves 360° phase modulation with a transmission magnitude exceeding 0.85 while being lightweight and cost-effective. Based on the unit, three metasurface arrays are developed to achieve various focusing functions, including single-point offset focusing, dual-point focusing, and multi-focal energy-controlled focusing, offering over 15% operational bandwidth and maintaining satisfactory performance under a 25° oblique incidence, with respective efficiencies of 35.59%, 25.11%, and 33.42%. This work provides a novel solution for multifunctional focusing applications, expanding the potential of metasurfaces in wireless communication, wireless power transfer, and beyond.