Periodic wavelet expansions for analysis of scattering from metallic cylinders

The recent application of wavelet transforms in method‐of‐moments solutions for scattering problems is extended to cases involving metallic cylinders whose periphery contain a variety of length scale features ranging from smoothly varying large‐scale features to rapidly varying small‐scale ones. The basic idea is to first consider a periodic extension of the equivalent current in the arc‐length variable with a period identical to the scatterer circumference, and then to expand this representation, using a set of periodic wavelets derived from a conventional basis of wavelets by a periodic extension. Using a Galerkin method and subsequently applying a threshold procedure, a substantial reduction in the number of elements of the moment‐method matrix is attained without virtually affecting the solution accuracy. The proposed extension is illustrated by a numerical study of TM (transverse magnetic) scattering from a cylinder of elliptic cross section. © 1994 John Wiley & Sons, Inc.