Estimation of ground scattering in microwave links

Based on a ray theory of scatter, the paper shows that in a microwave link, over uniformly rough ground, the power scattered in the direction of the receiving antenna originates within a very narrow strip extending practically from the emitter antenna to the receiver antenna; for purposes of computing this power, a link with two antennas of equal height is completely characterised by a single parameter involving the height, the distance between the antennas and the ground roughness. It is also shown that, while for a very smooth ground all the scattered power originates in the region around the specular point, for rougher grounds an appreciable amount of power can originate from regions far from the specular point.