Broadband Radar Absorbers Based on Periodic Structures

in this paper, we present the design and characterization of two radar absorbers based on periodic structures. Near unity absorbance over a wideband frequency is achieved under normal, as well as oblique incidence of a linearly polarized (LP) electromagnetic (EM) planar waves. The reflected wave is measured for both transverse electric (TE) and transverse magnetic (TM) polarizations. The first absorber is a low profile monolayer periodic structure (height < wavelength/12). The measured absorption rate is >90% in the range of [5.6 - 9.1] GHz. The second structure is an ultra-broadband thin FSS based radar absorber. An absorption rate above 89% is obtained in the frequency band of [4.8–11.1] GHz. The absorption remains very interesting for oblique incidences; up to 30°. The total height is < wavelength/7. The theoretical thickness to real thickness ratio (limit height of ROZANOV is as high as 80%. The experimental results are in good alignment with the numerical results. The experimental results are very promising and our designs can be used to tackle EM interferences for a large domain of applications.