Simultaneous Infrared Camouflage, Radar Absorption, and Optical Transparency in Lightweight Metamaterials

ABSTRACT The rapid advancement of multispectral detection technologies highlights the crucial need for multifunctional stealth materials featuring radar microwave absorption, low infrared emission, optical transparency, and surface conformability. However, the synergistic regulation of multiphysics fields within ultrathin structures remains a persistent challenge. Herein, a lightweight multispectral metamaterial composed of patterned indium tin oxide and a thermoplastic polyurethane (TPU) honeycomb skeleton is proposed. By employing a design strategy of spatial stratification and electromagnetic functional decoupling, this study effectively overcomes the conflicting requirements of low infrared emissivity and microwave impedance matching on sheet resistance, thereby enabling the independent manipulation of electromagnetic responses across different frequency bands. Furthermore, the thin‐walled TPU honeycomb skeleton guarantees the lightweight nature of the material while endowing it with excellent mechanical toughness and quasi‐conformal capabilities. Experimental results demonstrate that at a thickness of 3.4 mm, the designed metamaterial achieves an effective absorption bandwidth covering 7.74–21.23 GHz, a visible light transmittance of 62.5%, and an infrared emissivity below 0.4, with an ultralow areal density of only 0.93 kg/m 2 . This work presents a viable technological route for the multispectral stealth and conformal protection of complex platforms, such as small unmanned aerial vehicles.