Tailored Multi-Scale and Flexible Metamaterial for Broadband Electromagnetic Wave Absorption and Infrared Stealth.

Radar-infrared compatible stealth materials are widely used in applications such as electromagnetic protection and infrared thermal surveillance. However, harmonizing radar absorption, infrared stealth, and mechanical flexibility is a difficult challenge. In this work, a flexible metamaterial absorber (SMMA) with a skin-like multi-scale structure capable of achieving radar-IR compatible stealth was fabricated by utilizing freeze-drying and screen-printing techniques. The geometric parameters of the resonant metasurface and the dielectric constant of the SiC@Polyurethane (SiC@Pu) aerogel were optimized through electromagnetic simulations. By integrating metamaterial and SiC@Pu aerogel, this architecture synergizes structural and material losses to significantly enhance electromagnetic wave absorption (MA) performance. The skin-like multi-scale design ensures that incident electromagnetic wave undergo effective attenuation and dissipation. The final SMMA achieves excellent broadband MA performance with an effective bandwidth of 9.27 GHz and a peak reflection loss of -44.3 dB, while significantly reducing the radar cross-section. Meanwhile, the hierarchically porous aerogel exhibits excellent thermal insulation, maintaining a surface temperature nearly 48°C lower than a 100°C heat source, thereby effectively suppressing the infrared signature. This research demonstrates a design strategy for skin-like, multi-scale metamaterial absorbers, providing a pathway toward advanced, flexible, radar-infrared compatible stealth materials.