Polarization-Independent Ultra-Wideband Metamaterial Absorber for Solar Harvesting at Infrared Regime.

This paper presents an ultra-wideband metamaterial absorber for solar harvesting in the infrared regime (220-360 THz) of the solar spectrum. The proposed absorber consists of square-shaped copper patches of different sizes imposed on a GaAs (Gallium arsenide) substrate. The design and simulation of the unit cell are performed with finite integration technique (FIT)-based simulation software. Scattering parameters are retrieved during the simulation process. The constructed design offers absorbance above 90% within a 37.89% relative bandwidth and 99.99% absorption over a vast portion of the investigated frequency range. An equivalent circuit model is presented to endorse the validity of the proposed structure. The calculated result strongly agrees with the simulated result. Symmetrical construction of the proposed unit cell reports an angular insensitivity up to a 35° oblique incidence. Post-processed simulation data confirm that the design is polarization-insensitive.