Biomimetic and bio‑inspired multispectral stealth materials: Design strategies, fabrication, and radar infrared performance

Biomimetic and bio-inspired approaches offer a promising route to next-generation multispectral stealth by combining structure-driven electromagnetic (EM) wave control with materials-level thermal regulation. This review synthesizes recent advances in biomimetic radar and infrared-stealth materials, focusing on biological design principles, fabrication strategies, EM- and IR-loss mechanisms, and multifunctional integration. We first summarize the theoretical basis of radar cross-section reduction and IR signature suppression, then categorize key bio-inspired motifs-moth-eye, lotus-leaf, spider-web, honeycomb, plant-derived and other hierarchical structures and discuss how each modulates scattering, impedance matching, multiple internal reflection, interfacial/dipolar polarization and conductive/magnetic loss to achieve broadband microwave absorption. Next, we review IR-stealth strategies inspired by polar bear fur, Saharan silver ants, cephalopods and other organisms for thermal insulation, emissivity control and adaptive camouflage. Representative fabrication methods-hydrothermal, electrospinning, templating, 3D printing, freeze-drying, CVD and metamaterial patterning and common compositional platforms including carbonaceous materials, MXenes, conductive polymers, ferrites and nanocomposites are compared with emphasis on process–structure–function links. We highlight examples of multifunctional stealth materials that simultaneously deliver low radar cross-section, reduced IR emissivity, mechanical robustness, superhydrophobicity and lightweight design. Finally, we identify current challenges-multispectral compatibility, environmental durability, thickness/weight constraints, and scalable manufacturing and propose future directions for integrated material structural optimization and active/adaptive stealth systems. This comprehensive review provides design guidelines and a roadmap for developing high-performance biomimetic multispectral stealth materials for aerospace, naval and wearable applications.