A broadband circuit analog absorber using resistively loaded square loops

Abstract

In this paper, a polarization-insensitive broadband circuit analog (CA) absorber has been presented. The proposed structure consists of three concentric square loops printed on a dielectric substrate, which is separated from the ground plane by an air spacer. The square loops are made of resistive inks that absorb incident electromagnetic wave and exhibit −10 dB absorption bandwidth over the frequency range of 3.93−9.18 GHz. The absorption mechanism of the structure has been explained by deriving an equivalent circuit model as well as analyzing surface current distributions. Furthermore, the proposed design is fabricated using screen printing technique, whose measured result shows good agreement with the simulated response under normal incidence.