Transparent broadband metamaterial absorber based on resistive films

Abstract

In this paper, an optically transparent metamaterial with broadband absorption is presented theoretically and demonstrated experimentally. The design comprises of structures made of resistive films of indium-tin-oxide and the metamaterial exhibits over 10 dB absorption in the frequency range of 6.06–14.66 GHz. The novelty of the structure lies in its large absorption bandwidth along with a reduced thickness and optical transparency compared to broadband absorbers reported earlier. Besides, the proposed design is polarization-insensitive and gives rise to angular independent absorption for both transverse electric and transverse magnetic polarizations. The absorption mechanism in the structure has been studied by deriving an equivalent circuit model as well as analyzing several design parameters. Finally, a prototype of the proposed structure has been fabricated and measured, which shows good agreement with the simulated results.