A microwave metamaterial absorber with wide bandwidth

A wideband metamaterial absorber has been presented for practical applications in this article. The unit cell of the proposed structure comprises metallic patch of single circular split-ring imprinted on top surface of a metal-backed single layer dielectric substrate. The geometrical dimensions of the structure are suitably optimized so that full width half maxima bandwidth of 11.46 GHz is realized along with wideband absorption of 10.90 GHz from 5.94 GHz to 16.84 GHz with more than 80% absorptivity. Four distinct absorption peaks are observed at 6.46 GHz, 10.24 GHz, 15.26 GHz and 16.66 GHz. The absorption phenomena at these four frequencies are analyzed and the roles of several geometrical parameters of the design are investigated. The proposed structure has been studied under oblique incidence, both for TE and TM polarizations where it shows wideband absorption characteristics upto 45° incident angles for both cases. The proposed structure is very thin (~ λ/8.3 with respect to the centre frequency of the absorption bandwidth) compared to the commercially available microwave absorbers.