Design of a Wide-band, Miniaturized Absorber for S-and C-Band Applications

In this paper, an ultra-wide band absorber with miniaturized FSS element is proposed in S-and C-band (1.976.67 GHz) range. The constructed structure is based on a spiral type geometry arranged in each quadrant of single layer frequency selective surface (FSS). The spirals of adjacent quadrants cells are connected through resistors. The proposed configuration is polarization-insensitive due to the symmetric orientation of the elements. The proposed structure achieves a relative absorption bandwidth of 108.8%, with an absorption rate exceeding 90% across the entire absorption band. The structure has compact element size of $0.052 \lambda_{\mathrm{L}} \times 0.052 \lambda_{\mathrm{L}}$ (at the lowest frequency of absorption band). The operational mechanism of the constructed absorber is explained through corresponding surface current diagram and electric field distribution. The other eminent features of the proposed structure are its simple design and near unity absorptivity for both the polarizations.