A MULTIRESOLUTION STUDY OF 2-DIMENSIONAL SCATTERING BY METALLIC CYLINDERS

The recent application of wavelet transforms in method of moments (MoM ) solutions for scattering problems is extended to cases involving met allic cylinders whose periphery contains a variety of length-scale fea tures ranging from smoothly varying large-scale features (characterize d by a radius of curvature of several wavelengths) to rapidly varying small scale ones (characterized by a radius of curvature that is small compared with the wavelength), The basic idea is to first consider a periodic extension of the equivalent current in the arc-length variabl e with a period identical to the scatterer circumference, and then to expand this representation using a set of periodic wavelets derived fr om a conventional basis of wavelets by a periodic extension, Using a G alerkin method and subsequently applying a threshold operation, a subs tantial reduction in the number of elements of the moment-method matri x is attained without virtually affecting the solution accuracy, The p roposed extension is illustrated by a numerical analysis of TM (transv erse magnetic) and TE (transverse electric) scattering from a cylinder of elliptic cross section, A thorough study is carried out showing ho w the solution accuracy improves with increasing resolution level, and how this accuracy is affected by a thresholding process which renders the moment matrix sparsely populated.