Double Layer Absorber with Resistor Loaded Square Loop with Trapezium Sides and Jerusalem Cross Extensions

This paper presents a novel structure of an absorber which has wide bandwidth and low thickness. It consists of two FR-4 dielectric substrates separated by an air gap. The frequency selective surface (FSS) is present on the top substrate and contains a resistor loaded square loop rotated at 45 degrees. Each side includes a trapezium which has a lumped resistor. A Jerusalem cross extension is present at each vertex of the square loop. The proposed structure has a bandwidth of 113% from 2.24 GHz to 8.24 GHz, periodicity of
$0.185\lambda_{l}$
(wavelength of the lowest operating frequency) and a thickness of
$0.085\lambda_{l}$
. This absorber is suitable for wide band applications where low thickness is necessary.