Asymptotic analysis of propagation over cluttered parabolic ridges

Abstract

Analysis of radio propagation over varying, clutter-covered terrain was carried out aiming at prediction of power received by a terminal immersed in clutter, with the transmitter placed above clutter. The need for such prediction arises, for example, in planning and assessing coverage and interference in radio communications. Following a general formulation of the problem, particular solutions were found when the terrain has constant curvature. Asymptotic evaluation yielded compact expressions for parabolic ridges. Ray-optical term dominated for short ranges, while a single mode dominated at large ranges. Ridges produced strong blockage beyond the “horizon”, in contrast to strong focusing reported to occur in valleys. The resulting procedure for predicting pathloss over varying terrain is therefore to apply the formulae using the terrain curvature extracted from terrain files.