Bistatic properties of Kirchhoff diffractals

The angular dependence of wave intensity scattered from two types of fractal surfaces is calculated and analyzed within the physical optics approximation. The focus is on surfaces whose dimensions are close to the dimension of a Brownian fractal surface. It is shown that the effect of diversification of the angular patterns in the case of bistatic scattering manifests itself as a transition from the single-to the double-peaked form of the scattering indicatrix and takes place when the wavelength is of order of the topothesy of the surface. In addition, the effect of the small-wavenumber cutoff is quantified.