DIRECTIONAL SPECTRUM MODELLING IN INHOMOGENEOUS FORESTS AT 20 AND 62.4 GHZ

This paper presents a radiowave propagation model for inhomogeneous forests based on the Radiative Energy Transfer theory (RET) model. This model, which is a discretised version of the RET, is able to simulate the behaviour of radiowaves inside a forest which contains various types of vegetation and free space gaps. The forest is divided into non-overlapping square cells, each one with different propagation characteristics. The propagation properties of each cell rely on specific propagation parameters, which are extracted from vegetation using an appropriate measurement method which is also described. The model performance is assessed through comparison between predicted values and directional spectrum measurements carried out in an isolated inhomogeneous forest at 20 and 62.4 GHz. This forest, located in South Wales, is formed by 6 different species of trees of various sizes and leaf types. The measurements were performed with the trees in-leaf.