Visible-Infrared Transparent Coding Metasurface Based on Random Metal Grid for Broadband Microwave Scattering

The broad applications of manipulation of electromagnetic waves (EMWs) in imaging, detection, communication, and electronic countermeasures have drawn extensive attention to the metasurface. In these applications, maintaining transparency to visible light is challenging, especially when high transmittance in the infrared band is also required, not to mention when the substrate is a nondevelopable surface. Although ITO-based metasurfaces can transmit visible light, ITO cannot transmit infrared and has poor mechanical properties, coupled with shortcomings such as the scarcity of indium, which together limit their application. Here, the random metal grid and coding metasurface are first integrated, which achieves a random metal grid-based coding metasurface (RMGCM), for flexible microwave manipulation while maintaining high transmittance from visible to infrared. As a proof of principle, a polarization-insensitive, broadband range (19-23 GHz) RMGCM that can scatter microwaves over a wide angle range of 0 to 45° is obtained. The uniformity of the stray light of the random metal grid and the good substrate compatibility of its fabrication technique, coupled with the powerful ability of the metasurface provide RMGCM with broad application prospects. One of the potential applications is the cockpit of a stealth aircraft that requires virtual shaping. In addition, combined with flexible substrates and random metal grids with smaller periods, this structure can be further improved to extend to wearable devices and terahertz fields.