الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Multipath (MP) propagation due to the presence of ”s’
table and extended superrefracti ve layer in the lower
iEroposphere and / or ground reflection are the major source
propagation outage on microwave line-of-sight (LOS)
links.
Models have been proposed to describe this phenomenon .• In this work we try to study two parameters usually neglec-
ted in most previous models. These are the effect of ground reflections on the selectivity of tropospheric multipath propagation and the effect of the presence of a horizontal variation in the refractivity along the ray path on
medium transfer function.
Ground reflections have always been neglected in ray
tracing models based on the fact that on well designed over land links, the amplitude of the reflected rays are usually
negligible. In our study we show that when the direct ray is deeply faded, the ground reflected ray may be the
crucial factor in determing the selectivity of this phenomenon. We considered the cases of the reflection from
both smooth and rough terrain. We then proposed a method to
determine the reflection point from an inclined terrain.
The effects of the assumption of the presence of variations of the refractivity on the ray path is then demonstrated. This can help to explain
of the anomalous propagation measurements on links 9 along the interface between two different terrains
as in coastal areas.
Finally, the results of experiment measurements of
inversion in Alexandria are shown.