Cross-scale Material-Structure Synergy for 2D Metamaterials: Toward Customizable Intelligent Electromagnetic...

Electromagnetic (EM) low-observable technology is increasingly expected to simultaneously deliver ultrathin geometry, broadband response, dynamic adaptability, and multispectral compatibility -capabilities that conventional stealth materials struggle to achieve because of intrinsic constraints such as the Rozanov and Snoek limits and their largely static responses. This review systematically examines recent advances in two-dimensional metamaterials (metasurfaces) from the perspective of cross-scale material-structure synergy, with particular emphasis on customizable and intelligent electromagnetic manipulation across multiphysics domains. We first discuss conventional lossy and signature-controllable materials and identify their performance bottlenecks. We then examine the fundamental mechanisms underlying metasurface-enabled regulation, including wavefront shaping, localized resonance, and spatial dispersion, and review representative advances in EM, thermal, optical, and acoustic stealth. Particular attention is given to active tuning through electrical, optical, thermal, magnetic, and mechanical stimuli, as well as programmable coding, data-driven inverse design, artificial intelligence, multispectral compatibility, and multifunctional integration. Finally, key challenges in conformal integration, environmental robustness, scalable fabrication, and coordinated multifunctionality are identified, and future opportunities in embodied intelligence, bionic design, embedded sensing-control, low-cost manufacturing, and standardization are discussed toward adaptive, intelligent, and multifunctional low-observable systems.