Electromagnetic properties of conventional radar absorbing materials (RAM) make it difficult to use them to provide remarkable surface electromagnetic waves (SEMW) attenuation with thin thickness at low radar frequencies such as in the UHF and L bands. In this paper, a composite structure realized by a grounded RAM slab covered by a resistive sheet is proposed. The use of a resistive sheet results in a significant increase of SEMW attenuation performance at low frequency, but almost no increase in its thickness. The electromagnetic scattering properties for a target coated with the RAM with/without covered by a resistive sheet are considered for interpreting the improvement of SEMW attenuation with resistive loading. Using a method-of-moments (MoM) computational scheme, we explore the performance of the proposed composite structure as radar backscattering suppression for a metal slab at low radar frequencies. It is found that the RAM with resistive loading has significantly increased SEMW attenuation at low frequencies, and advances the large incidence angle or grazing angle mono-static radar cross section (RCS) reduction of the coating slab further than the RAM without resistive loading case.
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