Design of Frequency Selective Surface-Based Hybrid Nanocomposite Absorber for Stealth Applications

This paper presents the design, fabrication, and electromagnetic testing of a frequency selective surface (FSS)-based novel hybrid nanocomposite absorber for enhanced electromagnetic absorption. The proposed hybrid absorber consists of an FSS pattern printed over a dielectric substrate backed by aluminum foil, which is integrated together with a customized dielectric nanocomposite sheet. The dielectric sheet comprises the conducting carbon black (CB) nanopowders embedded into the epoxy matrix. The fabricated nanocomposite sheet is first characterized for the effective complex permittivity using the free-space measurement technique, and the measured electromagnetic properties are then used for the design of a hybrid absorber. The proposed hybrid absorber having overall thickness of 2.6 mm shows enhanced -10-dB absorption bandwidth of 3.5 GHz, which is much higher than that of the FSS and CB nanocomposite samples measured individually. The proposed work provides an effective way to combine the absorption properties of FSS with that of a customized dielectric absorber sheet in order to design an efficient hybrid absorber having reduced thickness with enhanced absorption bandwidth for stealth technology and various strategic applications.