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摘要
Creeping waves play an important role in the analysis of electromagnetic scattering by large objects with curved boundaries. In this paper, an asymptotic model is presented for the back-scattered field on a dielectric-coated cylinder at aspect angles near broadside incidence, a region where the creeping wave has maximum intensity. The monostatic radar cross section is analytically derived from creeping wave poles and their residues, and is validated with data extracted from rigorous method of moments computation of the scattered field by utilizing a novel state space spectral estimation algorithm. Detailed computations reveal a stark contrast between dielectric-coated objects and uncoated metallic ones with regard to creeping wave propagation. Because of smaller curvature-induced leakage and coherent interaction between incident wave and the dielectric coating, creeping waves, strongly attenuated by metallic objects, become quite pronounced for coated objects. As the frequency increases, the creeping waves are partially trapped inside the dielectric layer and the scattered field becomes quite small. Therefore, in contrast to leakage on a metallic cylinder, which displays smooth monotonic reduction in amplitude with increasing frequency, creeping waves on a coated cylinder exhibit a strong cutoff akin to a guided wave.
- 出版日期2010-10-20
