Moment method simulation of rough surface scattering based on wavelet representation

The electromagnetic wave scattering from randomly rough surfaces is studied by means of moment method using the wavelets to represent the surface tangential fields or currents. Conventional moment method usually forms the matrix by uniform sampling. Since the density of the surface currents is dependent on the roughness of the surface, or more precisely the surface local slope. As a result, the matrix usually is densely distributed. When the surface becomes rougher or wavelength is larger, the size of the matrix is extremely large which is computational prohibitive. By making use of the wavelet expansion, due to its highly localized and adaptive sampling properties, the pattern and size of the resulting matrix can be accordingly adjusted. This merit is especially well suited for the simulation of rough surface scattering, particularly in the problems of three dimensional surfaces. In this study, the authors adopt the orthonormal and compactly supported wavelets proposed by Daubechies. The dependence of the number of coefficients on surface roughness, correlation function and wavelength are investigated. Then the validity and performance of the proposed approach is evaluated and tested on a broad range of parameters