Electromagnetic propagation in urban areas

Propagation in the urban environment is in principle a well-posed problem: the electromagnetic field radiated by prescribed sources, in the simplest case a single antenna, must fulfil Maxwell equations in the open space and boundary conditions over the built-up buildings walls. But any attempt to provide a solution to this apparently simple problem must face the complication of the scattering scenario. A general frame to locate above mentioned problem is certainly desirable, if not necessary. This point is examined in the paper.