Thin electromagnetic absorber design using HIS approach

This work explores the special characteristics of frequency selective surfaces (FSS) to designing electromagnetic absorbers, having extensive applications in communication (i.e. WIMAX and WLAN, aiming IEEE 802.11a standards) and radar systems. For this purpose, an alternative technique based on equivalent circuit model in conjunction with full wave simulations is proposed. The present model uses the resonant behavior when a FSS periodic grid lies over a grounded dielectric slab, and the optimal FSS parameter values to achieve absorption. By using the High-Impedance Surface (HIS) approach and extracted FSS parameter, the absorber are designed and implemented. Measurement results show excellent agreements with theoretical results and the method validity. The final structure has 3 mm thickness only, while provides almost 30 dB absorption at 5.5 GHz frequency band.