Design of Circuit Analog Absorber Using Swastika Geometry With Split Square Rings

This paper presents a novel, low profile Frequency Selective Surface (FSS) absorber with low periodicity and good angular stability. The FSS geometry consists of a lumped resistor loaded Swastika structure along with a split square ring placed in each of the four quadrants formed by the Swastika. The absorber has a minimal profile of 0.076 wavelengths at its lower -10 dB cutoff frequency with a fractional bandwidth of 100.83 % (1.79 GHz - 5.43 GHz) covering the the entire S-band and parts of the L- and C- bands. The design has four fold symmetry and is polarization insensitive. The equivalent circuit model is also presented to provide physical insight into the operation of the absorber.