Wideband Circuit Analog Absorber Using Modified Resistive Cross-Dipoles

In this paper, a novel circuit analog absorber design is proposed using resistive cross-dipoles as the basic template. The absorber consists of two FR4 substrates separated by air. The top substrate consists of a modified cross-dipole frequency selective surface (FSS) having lumped resistors and the bottom substrate provides a ground plane. The proposed absorber has a very low profile of 0.0739 wavelengths at its lowest operating frequency and a fractional bandwidth of 100.55% from 3.13 to 9.46 GHz. The designed absorber is insensitive to incident polarization and shows stable performance at oblique angles of incidence. It is demonstrated that a slight modification in the form of a rectangular strip applied to the basic cross-dipole FSS reduces the thickness to bandwidth ratio of the absorber.