An Ultrathin Penta-band Polarization-insensitive Compact Metamaterial Absorber for Airborne Radar Applications

In this article, an ultrathin penta-band polarization-insensitive metamaterial absorber has been presented, which consists of an array of a closed ring embedded in a tetra-arrow resonator. The proposed ultrathin (~k0/18 corresponding to the highest absorption frequency) structure exhibits five distinct absorption peaks at 3.4, 8.34, 9.46, 14.44, and 16.62 GHz with peak absorptivities of 98.6%, 96.6%, 90.1%, 97.8%, and 93.1%, respectively. Due to fourfold symmetry the structure provides nearly unity absorption for all polarization angles under normal incidence. The structure also exhibits high absorption peaks (~80%) up to 458 incident angles for both TE and TM polarizations. Surface current and electric field distributions for different absorption frequencies have been analyzed to visualize the absorption mechanism of the structure. Finally, the structure has been fabricated and experimentally measured responses are in good agreement with the simulated ones. VC 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2519–2524, 2015; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.29365