Design and optimization of Broadband FSS based Radar Absorbing Structure

In this paper, a thin broadband frequency selective surface (FSS) based radar absorbing structures (RAS) is presented for stealth application. The EM design and analysis of cross dipole FSS based radar absorber is carried out using equivalent transmission line method for the fractional bandwidth of 79.69%. Further, genetic algorithm based optimization procedure is implemented with equivalent circuit method (ECM), which aids in design of a broadband nonmagnetic absorber with FR4 substrate of minimal thickness. It is observed that the absorption characteristic is affected significantly by resistively loaded lossy FSS's element geometry as well as the substrate parameters. It is demonstrated that it is possible to design single layer wideband RAS using basic FSS structures with proper optimization techniques.