Analysis of the Relation Between Fresnel Zone and Path Loss Exponent Based on Two-Ray Model

In this letter, the underlying factor that leads to the change of path loss exponent
n
is investigated, using a reasonable and reliable indirect demonstration that is based on the simple two-ray model and a developed multiray model. It is found that the first Fresnel zone is the underlying factor that affects
n
.
n
will change only if the situation of the obstacles in the first Fresnel zone changes. The conclusion helps to understand the essences of the propagation.