An ultrathin quad-band polarization-insensitive wide-angle metamaterial absorber

Abstract

In this article, an ultrathin quad-band polarization-insensitive wide-angle metamaterial absorber has been presented. The proposed structure consists of a periodic array of concentric square and circular rings imprinted on grounded FR-4 dielectric substrate. The simulated result shows that the structure has four discrete absorption peaks at 3.91, 5.16, 7.10, and 9.16 GHz with peak absorptivities of 99.35, 98.04, 99.85, and 99.78%, respectively. The proposed structure is symmetric in design providing nearly unity absorption for all polarization angles under normal incidence. It also shows high absorption (∼90%) for wide incident angles upto 45° for both transverse electric and transverse magnetic polarizations. By illustrating surface current distribution, the absorption mechanism of different parts of the proposed structure has been analyzed. Finally, the structure has been fabricated and the measured results are in good agreement with the simulated responses. The designed quad-band absorber is easy to manufacture and can be used in various potential applications. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:697–702, 2015