A 3D Fourier split-step technique for modelling microwave propagation in urban areas

The paper presents a 3D extension of a full wave propagation model based on the Fourier split-step technique for solving the parabolic approximation to the scalar wave equation. Numerical implementation has been thought for application of propagation in urban areas where effects due to the Earth curvature and to an inhomogeneous atmosphere are negligible. It has been obtained by generalizing the 2D case by means of 2D direct and inverse Fourier transforms and can be used both for a low and a wide angle formulation. Some problematic features related to the necessary boundary conditions for modelling ground and obstacle faces reflections are treated. As examples of application two cases are reported. The first concerns the diffraction by a single perfectly conducting block-shaped building for a vertical and horizontal polarized incident field while the second is a simulation study of what may happen to a point-to-point urban radio link partially obstructed by the presence of a building when a second one is added close to the first