Return loss enhancement of surface resistors loaded microwave radar absorber

In this paper, return loss enhancement of a compact ultra-thin microwave radar absorber is demonstrated, The absorber is designed using textured surface technology comprised of a high impedance surface (HIS) positioned directly behind the anisotropically resistive-elements interconnecting a textured surface of square patches. By the selection of appropriate choice of the required surface resistors based on elementary circuit principles the return loss of absorber can be significantly improved. The properties of absorber are numerically characterized under normal incident using a parallel plate waveguide (PPW) simulator. It is demonstrated for this arrangement 27.09 dB at 3.14 GHz reflection loss can be obtained with an effective working bandwidth of up to 10% at 10 dB reflection loss. In addition it is shown that the bandwidth is insensitive to the small different values of resistive-element.