Design and simulation of a wideband, wide-angle and polarization-insensitive microwave absorber based on pattern optimization of resistive films

A wideband, thin, and multilayer (planar) microwave absorber is designed in this paper. The absorber is a periodic array of cells which includes three patterns of resistive film on two dielectric substrates. To design the array's cell, a pattern optimization procedure based on the application of a binary optimization algorithm was utilized. The outcome of this procedure is a pixelated pattern of resistive film yielding the maximum possible absorption bandwidth (BW) and a high insensitivity to the polarization of the incident wave. Our pattern-optimized design achieved a 90%-absorption rate over a wide frequency BW of 1.6 to 23.7 GHz (175% fractional BW) under normal incidence. Moreover, the absorber operates over a wide range of incidence angles for obliquely incident waves. (paper)