Compact ultrathin conformal metamaterial dual-band absorber for curved surfaces

A compact, ultrathin conformal metamaterial dual-band absorber for curved surfaces has been presented in this article. The absorber unit cell composed of circular and split ring resonators which are connected with plus-shaped structure. The proposed absorber unit cell is compact in size (0.22 lambda(o) x 0.22 lambda(o)) and as well as ultrathin thickness (0.006 lambda(o)), where lambda(o) is the wavelength at 5.8 GHz. The designed absorber gives two absorption tips at 5.8 and 7.7 GHz with more than 90% absorptivity. The full width at half maximum bandwidths are 220 MHz (5.67-5.89 GHz) and 250 MHz (7.58-7.83 GHz). The proposed conformal absorber is sensitive to the polarization angle and has a stable absorptivity over a wide range of incident electromagnetic wave. The parametric analysis and equivalent transmission line model have been investigated. The surface current and electric field distribution also discussed for understanding the absorption mechanism. To analyze the performance of proposed absorber on the curved surfaces, it is wrapped on the different radius of cylindrical surface and measured the absorptivity. Simulated and measured results have good agreement between them.