An ultra-light, low-cost reflecting/absorbing dual-mode metasurface

This paper presents an ultra-light, low-cost reconfigurable metasurface functioning as both reflector and absorber, with mode switching via a lossy electromagnetic bandgap (EBG) layer. In reflection mode, the reflecting EBG (REBG) structure exhibits in-phase reflection characteristics at 2.48 and 5.84 GHz, with its dual-band operation achieved through a square patch configuration. In absorption mode, the integration of a lossy EBG layer atop the REBG enables relatively wideband absorption, while preserving insensitivity to polarization and exhibiting stability against varying incident angles. The absorption band fully encompasses the reflection band by employing an artificial intelligence (AI)-driven antenna optimization technique, specifically, the self-adaptive Bayesian neural network surrogate model-assisted differential evolution for antenna optimization (SB-SADEA) method. With a peak absorption rate reaching 99 %, the developed prototype sustains over 90 % absorption efficiency throughout the 2.2–7.28 GHz band. Additionally, this structure can isolate thermal infrared radiation, achieving both electromagnetic and infrared camouflage capabilities, with an infrared emissivity as low as 0.06. Two co-fabricated textile monopole antennas were experimentally characterized with the REBG to validate reflection behavior. The metasurface boosts realized gain by 5 dB at 2.48 GHz and 5.84 GHz. Consistent agreement between simulations and measurements proves the dual-mode metasurface’s efficacy.