An Ultrawideband Miniaturized Ultrathin Flexible Metamaterial Absorber Using Lightweight ITO Film

This letter presents an ultrawideband miniaturized ultrathin flexible metamaterial absorber (MMA) based on frequency selective surface (FSS). The proposed MMA consists of an inner planar helix and four groups of outer convoluted lightweight indium tin oxide resistive film etched on a transparent substrate polyethylene terephthalate substrate. The MMA demonstrates stable absorption across the frequency range of 1.98 to 25.88 GHz, achieving a remarkable maximum fractional bandwidth of 171.6%. The unit cell size of the MMA is 0.06 lambda(L)x0.06 lambda(L)x0.035 lambda(L), where lambda(L) represents the wavelength corresponding to the lowest absorption frequency. The structure can cover both the L-and S-bands without increasing its size and achieve stable absorption under a curved surface. Therefore, it is suitable for low-frequency applications such as satellite navigation systems and satellite communications.