Metasurface-Aerogel-Composite Reconfigurable Electromagnetic Functional Surface with Thermally Robust and Ultra-Wideband Stealth via Hybrid Absorption-Diffusion Mechanisms.

Electromagnetic functional surfaces capable of multimode electromagnetic (EM) reconfiguration and reliable operation under extreme thermal environments are highly desirable for advanced aerospace and defense systems. However, simultaneously achieving flexible functional switching, ultra-wideband stealth capability, and thermal robustness remains challenging. Here, a metasurface-aerogel-composite reconfigurable electromagnetic functional surface (REFS) is proposed. The proposed architecture consists of three key components: an absorption-transmission resistive metasurface (AT-RMS) for low-frequency wideband absorption, a transmission-scattering diffusive metasurface (TS-DMS) for high-frequency wideband diffuse scattering, and an aerogel composite layer for thermal protection and impedance optimization. Through the synergistic integration of these functional components, coordinated absorption loss and scattering manipulation are achieved, enabling ultra-wideband radar cross-section (RCS) reduction outside the operating band while maintaining low-loss in-band transmission performance. Furthermore, PIN diode-based reconfigurable elements enable dynamic in-band switching among transmission (T), reflection (R), and absorption (A) states, while the polarization-independent biasing strategy further extends the reconfigurability to nine distinct operating modes. The employed aerogel composite not only provides effective thermal protection with an ultralow thermal conductivity of 0.0176 W/(m · K) but also improves impedance matching through its low permittivity, thereby enhancing the overall EM performance. A 10 × 10 array prototype is fabricated and experimentally characterized to verify the multifunctional and thermally robust performance of the proposed REFS. The fabricated prototype achieves stable T/R/A reconfigurable operation within 5.74-6.23 GHz, a 7-dB ultra-wideband RCS reduction from 2.18 to 17.86 GHz in the transmission state, and maintains stable EM performance after exposure to 600 K for 1 h. These results demonstrate a promising strategy for integrating thermal protection, multimode EM reconfigurability, and ultra-wideband stealth capability into advanced aerospace electromagnetic skins and multifunctional stealth radome systems.