PERIODIC WAVELET EXPANSIONS FOR ANALYSIS OF SCATTERING FROM METALLIC CYLINDERS

The recent application of wavelet transforms in method-of-moments solu tions for scattering problems is extended to cases involving metallic cylinders whose periphery contain a variety of length scale features r anging from smoothly varying large-scale features to rapidly varying s mall-scale ones. The basic idea is to first consider a periodic extens ion of the equivalent current in the arc-length variable with a period identical to the scatterer circumference, and then to expand this rep resentation, using a set of periodic wavelets derived from a conventio nal basis of wavelets by a periodic extension. Using a Galerkin method and subsequently applying a threshold procedure, a substantial reduct ion in the number of elements of the moment-method matrix is attained without virtually affecting the solution accuracy. The proposed extens ion is illustrated by a numerical study of TM (transverse magnetic) sc attering from a cylinder of elliptic cross section. (C) 1994 John Wile y & Sons, Inc.