Super compact ultrathin quad-band with wide angle stability polarization independent metamaterial absorber

In this article, a compact ultrathin polarization-insensitive wide-angle metamaterial-based microwave absorber with quad-band characteristics is presented. The designed microwave absorber provides simulated peak absorption of 99.16%, 98.21%, 98.32%, and 99.76% at 3.7 GHz, 6.4 GHz, 10.7 GHz, and 14.3 GHz, respectively. The absorption frequency lies in microwave frequency bands of S, C, X, and Ku. The unit cell of the proposed microwave absorber consists of two diagonally connected closed ring resonator (CRR) along with one metallic patch enclosed by the inner CRR. Each side of the enclosed patch is connected with inner CRR at the center of length. The unit cell of the proposed 0.0197 lambda(lowest) (wavelength at lowest frequency) thick multiband absorber fits in a volume of 8 x 8 x 1.6 mm(3). The proposed metamaterial-based microwave absorber exhibits identical absorption characteristics for both transverse-electric and transverse-magnetic polarized radiations and also provides well peak absorption for an oblique incidence up to 75 degrees. Finally, the absorber is fabricated and experimental result validates simulated one.