Scattering by randomly rough dielectric surfaces and rough dielectric films: influence of the height distribution

Scattering of electromagnetic waves by randomly rough surfaces can be modelled efficiently by perturbation theory if the root mean square (rms) height is smaller than 0.061. In this regime, the angular scattering pattern depends strongly on the correlation length a. It will be shown that for penetrable media, the height distribution strongly influences the angular scattering pattern. This property is illustrated with two different systems: a randomly rough dielectric surface and a rough dielectric film deposited on a perfectly conducting substrate. A model recently introduced (mean-field theory) yields a physical explanation of this behaviour. This approach is used to analyse the fringes produced by a randomly rough dielectric film deposited on a flat reflecting susbtrate. It is shown that the features of the fringes can be explained when accounting for the height distribution.