Estimation of roughness-induced power absorption from measured surface profile data

We present a methodology for extracting the 2-D power spectral density of a statistically isotropic random rough surface from height measurements by utilizing fast Fourier-Bessel transform. We compute the additional propagation loss due to surface roughness by integrating the extracted spectral density via the formula of absorption enhancement factor. Results for a microstrip demonstrate good correlation between measured and estimated loss up to 20 GHz. It is also possible to choose a random rough surface model for the measured surface and use it to predict the roughness effect on power loss.