Implementation of the integral equation model for rough surfaces with generic isotropic autocorrelation functions

An implementation of the integral equation model applicable to rough isotropic surfaces is presented which makes use of Fourier transform numerical methods to compute the surface spectrum. Different approaches for performing the calculations are compared in terms of computational accuracy and efficiency. Optimum values for window size and sampling step are reviewed and illustrated in practical cases depending on the surface autocorrelation function and the operating frequency.