Multi-spectral functional metasurface simultaneously with visible transparency, low infrared emissivity and wideband microwave absorption

Abstract

In this paper, we propose the design of an optically transparent metasurface with simultaneously wideband microwave absorption and low infrared (IR) emissivity. To this end, two optically transparent functional layers are firstly designed using indium-tin-oxide (ITO), which can suppress IR emission and achieve wideband microwave absorption, respectively. The two functional layers are then combined together to construct the multispectral metasurface. By properly tuning the structural parameters and sheet resistance of ITO, a wide microwave absorption band can be achieved with absorption higher than 90%. Low IR emissivity of about 0.30 is obtained by controlling the occupation ratio of ITO on the front side structure of the metasurface. A prototype was fabricated and measured. The measured results show that the averaged transmittance of visible light through the metasurface reaches up to 62.4% and the high-efficiency microwave absorption can be achieved in 11.2–33.9 GHz, with absorption rate higher than 90%. Good consistency between the experiment and simulation results convincingly verifies the metasurface. Due to its multispectral compatibility, the proposed metasurface may find potential applications in multi-spectral stealth, camouflage, etc.