Ultra broadband and wide angle microwave absorber based on integrated coding metasurfaces

A 3D ultra broadband and wide-angle microwave absorber based on integrated coding metasurfaces is presented, combining polarization independence, optical transparency, and high absorption performance. The proposed absorber employs a stereo structure composed of transparent ITO patterns on polymethyl methacrylate (PMMA) substrates, optimized using a genetic algorithm (GA) for efficient coding design. By integrating vertical and bottom metasurfaces with centrosymmetric coding patterns, the absorber achieves over 90% absorption from 5 to 40 GHz for both transverse electric (TE) and transverse magnetic (TM) waves, maintaining wide-angle stability up to 50°. Even at extreme angles (50°-70°), the absorber retains over 80% absorption across a broad frequency range. Numerical simulations and experimental measurements confirm the design's effectiveness. Furthermore, the structure exhibits high optical transparency in the visible spectrum, enabling dual-functionality for electromagnetic stealth and optical visibility. The proposed approach offers a versatile and scalable solution for broadband, wide-angle absorbers, with potential applications in electromagnetic shielding, camouflage, and multi-spectrum stealth technologies.