Ultrathin wideband polarization independent compact metamaterial microwave absorber

Abstract

In this article design, fabrication and analysis of a compact ultrathin polarization independent wideband metamaterial absorber at microwave frequency is presented. The unit cell of the proposed design constitute of a metallic 12-point star with center cavity and dual half slot at 45° imprinted on top of the grounded FR4 dielectric substrate. The numerical result exhibits full width at half maximum (FWHM) bandwidth of about 16.3% from 1.92 GHz to 2.26 GHz with absorption of above 80%. The absorption mechanism of the presented absorber has been analyzed through parametric variations, electric field distributions and surface current distributions. In addition, absorption of about 70% is achieved at wide angle of incidence up to 45°. The polarization independence is verified via waveguide method by setting distinct orientation angles for the unit cells. Measured results are in agreement with the simulated results. The designed absorber is compact and ultrathin with unit cell size and thickness of less than 0.25λ 0 and λ 0 /45 at center frequency of absorption.