Study of Wideband, Wide Angle, Polarization Independent Metamaterial Hilbert Curve Absorbing Screen for Terahertz Bolometers

A wideband, wide angle metamaterial Hilbert curve array terahertz absorbing screen is reported. The absorber consists of array of an Aluminum first order Hilbert curve array over a copper ground plane separated by dielectric spacer. 100% fractional bandwidth (-3dB absorption bandwidth) for normal incidence and more than 90% in case of oblique incidence of 45 degrees and 60 degrees for both TE and TM polarizations have been verified numerically. The operating bandwidth of the structure proposed here is several times of those reported to date. Peak absorption is 98% for normal incidence and more than 86% for 60 angle of incidence for either polarization. Furthermore, effects of variations in Hilbert curve dimensions, spacer thickness, spacer permittivity and ground plane conductivity are also investigated. The structure is shown to have high tolerance to variations in the aforementioned parameters.