An ultra-wideband miniaturized ultrathin flexible metamaterial absorber using lightweight ITO film

This paper presents an ultra-wideband miniaturized ultrathin flexible metamaterial absorber (MMA) based on frequency selective surface (FSS). The proposed MMA consists of an inner planar helix and four groups outer convoluted lightweight indium tin oxide (ITO) resistive film etched on a transparent substrate polyethylene terephthalate (PET) 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 $0.06 \lambda_L\times 0.06 \lambda_L\times 0.035 \lambda_L$ , 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 it can achieve stable absorption under curved surface. Therefore, it is suitable for low-frequency applications such as satellite navigation systems and satellite communications.