Electrodynamic properties of forests media in UHF range

摘要

Studies the dispersion properties and polarization features of a forest environment in the 0.1-1.0 GHz frequency range. The study of extinction coefficients must be based on a statistical approach, as major parameters of a forest environment are characterized by average values only. The cumulative effect of scatter and extinction observed in VHF propagation in a forest can complicate the picture of spatial distribution of signal amplitude and phase. The scattered component of a field causes 'quick' fluctuations in space of signal amplitude which finally makes the study of the relationship between extinction coefficient and distance more difficult. Therefore spatial fluctuations of the signal observed over several wave lengths must be averaged. The average signal strength thus obtained will be related to the average density of the forest which adequately correlates with the extinction coefficient /spl gamma/. It follows from the above that the spatial range of signal amplitude shows a certain regularity in the average only. In order to establish more precisely the relationship between the distance and extinction coefficient for different types of forests, a fairly wide range of experimental work was carried out covering all possible types of forests, varying in type and average density.