Spectral Camouflage Enabled by a Conformal Metasurface

Metasurfaces provide an ultrathin platform for electromagnetic-wave manipulation and have great potential in spectral camouflage like radar stealth and anti-counterfeiting. In this work, we propose a flexible time-modulated metasurface loaded with PIN diodes on a polyimide substrate. Driven by FPGA-generated pseudo-random maximal-length sequences, the metasurface dynamically switches its reflection phase and spreads the reflected signal into a broadband noise-like spectrum, thereby reducing its power spectral density. Simulations and measurements verify its radar-stealth performance. The metasurface also maintains effective spectral spreading when conformally mounted on curved surfaces, showing promise for practical stealth applications.