Metasurface Window With Customized Transparency for Sunlight and Switchable Transmission for Microwaves

In recent years, reconfigurable metasurfaces (RMs), as real-time controllable 2-D metamaterials, have become an emerging platform for manipulating spatial electromagnetic (EM) waves by loading dynamic components. To date, many RMs have been reported, most of which are without special considerations on optical transmittance or only support limited functions of absorption and reflection. In this work, we propose an optically transparent RM (OTRM) window simultaneously with customized transparency for sunlight-proof and switchable transmission of microwaves for EM pollution prevention. The metasurface window is based on an optically transparent substrate with a metallic mesh, which can reduce the proportion of opaque space required to customize the optical transmittance. The dual-layer rheostatic diodes implement dynamic control of transmission, absorption, and reflection of EM waves, including continuous modulation and complete switch-ON/OFF in the microwave band (5.2–6.4 GHz). The working mechanism of the metasurface in the microwave band was theoretically explained using the Drude model and the Lorentz model. A proof-of-concept prototype was designed, fabricated, and measured, further demonstrating sunproof optical transparency and switchable control of EM waves. This work may find applications in future 5G or 6G intelligent wireless communications for diverse EM modulations.