Measurements and modelling of propagation losses through vegetation at 1-4 GHz

The information on the propagation effects of the changing local environment at frequencies in excess of 1.5 GHz is scarce. Foliage in particular has been shown to be a major source of attenuation at both UHF and 1.5 GHz and is expected to provide higher attenuation as frequency increases. The results of an experimental field campaign conducted in Spring/Summer and Autumn/Winter at various spatial positions along the shadow of a mature deciduous tree with and without leaves readings at different foliage depths were recorded. From the experimental results, a relationship between the excess path loss due to the tree with and without leaves was derived. In addition to this, an exponential decay model based on a specific attenuation in terms of dB per metre of path length was derived. This model was then found to be appropriate for those situations where propagation is likely to occur through a grove of deciduous trees. The methodology is described