Metamaterial-inspired infrared electrochromic devices with wideband microwave absorption for multispectral camouflage

Abstract

Infrared (IR) electrochromic devices, capable of dynamically controlling thermal radiation, hold promising applications in adaptive camouflage. However, the strong microwave reflective properties inherent in the device’s electrodes present a significant challenge, rendering them susceptible to radar detection and weakening their camouflage effect. Inspired by the remarkable electromagnetic control capabilities of metamaterials, the integration of frequency selective surfaces into IR electrochromic devices is proposed to address this multispectral compatibility challenge. The designed integrated metadevices simultaneously exhibit large and reversible IR emissivity tunability (Δ ε ≥0.55 at 3–5 μm, Δ ε ≥0.5 at 7.5–13 μm) and wideband microwave absorption (reflection loss ≤−10 dB at 8.5–18 GHz). Furthermore, the monolithic integrated design of the shared barium fluoride substrate offers a simple device architecture, while careful design considerations mitigate coupling between IR electrochromism and microwave wideband absorption. This work introduces opportunities for the development of multispectral adaptive camouflage systems, offering potential advancements in concealment technology.