Visibly Transparent Tunable Water-Based Metamaterial for Microwave-Infrared Camouflage

In this article, we propose a novel transparent tunable water-based metamaterial (TTWM) to realize multispectral camouflage of visible light, infrared and microwave. By modulating the injection and discharge of pure water, the broadband switching function between the microwave absorbing state (6.0–34.9 GHz for transverse electrical (TE) mode and transverse magnetic (TM) mode) and the reflecting state (10.7–28.2 GHz) is realized. In combination with the inherent characteristics of the material, the TTWM achieves low emissivity (~0.25) in the infrared band (3– $14~\mu $ m) and an average optical transparency of 62%. Furthermore, it possesses wide-angle stability, polarization insensitivity, and excellent thermal stability. The unique attributes of this structure are substantiated through numerical simulations and experimental validation, indicating that our designed model holds significant promise for applications in multispectral camouflage field.