Transition zone diffraction by multiple edges

Abstract

In UHF radio wave propagation over multiple buildings or hills, obstacles are often in the transition region near the shadow boundary where ray descriptions fail. It is shown that proper inclusion of slope diffraction within the UTD (uniform theory of diffraction) gives a good approximate solution, allowing a ray description in these cases. Comparison is made with a known solution for a few edges, with the result that all the terms are included with the correct ratio of distances involved, albeit with somewhat different functional relationships.