Optically Transparent Metasurface With Multispectral-Compatible Camouflage and Millimeter-Wave Transmission Window

The continuous advancements in multimode detection and surveillance technologies have made multispectral-compatible camouflage increasingly vital for both defense and civilian applications. Meanwhile, stealth radomes require in-band communication of electromagnetic (EM) signals. This article presents a multifunctional metasurface that provides multispectral-compatible camouflage across visible, infrared (IR), and microwave regions while simultaneously enabling efficient transmission in the millimeter-wave (mm-Wave) band. The proposed system consists of bilayer indium tin oxide (ITO) patterned layers for low IR emissivity and broadband radar absorption along with a metal-meshed frequency-selective surface (FSS) layer for mm-Wave transmission. Both simulated and experimental results indicate that the fabricated sample exhibits more than 90% absorption over a wide microwave frequency band ranging from 7.6 to 16.4 GHz, while a transmission window with an insertion loss (IL) of 0.96 dB is realized at 27.9 GHz in the mm-Wave band. In the IR atmospheric window, the measured emissivity of the metasurface is 0.304 and 0.363 for 3–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5~\mu $ </tex-math></inline-formula>m and 8–<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$14~\mu $ </tex-math></inline-formula>m, respectively. Besides, the measured optical transparency reaches 51.7% in the visible wavelength range of 400–800 nm. This work presents promising opportunities for the engineering application of metasurfaces in optical windows, stealth radomes, and 5G mm-Wave communication systems.