Dual-spectrum transparent random encoding metasurface for scattering reduction and electromagnetic shielding

In this study, a dual-spectrum transparent random encoding metasurface (DTREM) is proposed to achieve both excellent radar cross-section (RCS) reduction and enhanced electromagnetic (EM) protection for advanced optical windows. To simultaneously ensure high EM shielding and excellent transmittance in the visible and infrared spectra, an easy-to-fabricate metal mesh technology is employed, with its physical parameter constraints analyzed theoretically. Subsequently, based on a practical simulated annealing algorithm, the optimized coding array is elaborately designed. This algorithm can significantly enhance the RCS reduction performance of DTREM. Experimental results show that the fabricated DTREM sample achieves a high dual-spectrum transmittance of 89.5% at 550 nm and 90.8% in the 3.0-5.0 μm range. Additionally, it demonstrates notable RCS reduction exceeding 10 dB across 13.6-17.2 GHz and a shielding effectiveness of 23.8 dB over the X-Ku band. These results suggest that the proposed approach offers a promising solution for integrated optoelectronic detection platforms.