A Compact Wide-band Absorber Based on Resistive FSS and Magnetic Materials

In this paper, we propose a thin and wideband electromagnetic absorber designed using a resistivity-controlled frequency selective surface (FSS) layered on a commercially available grounded magnetic substrate. Equivalent circuit analysis and accurate full-wave numerical simulations have been adopted to extensively evaluate the composite structure. The FSS unit cell is made of two concentric resistive loops with different values of surface resistivity. This structure has been layered on a 2.5 mm thick magnetic material, commercially available in the market. The optimized surface resistance values are influenced by the substrate properties (thickness and permittivity) as well as by the shape of the FSS element. Despite its reduced overall thickness, the structure can achieve a considerably wideband absorption within the 8-12 GHz band, covering the entire range with absorbing levels better than −10 dB.