Investigation of propagation in foliage using simulation techniques

Abstract

In a foliage environment, radio wave propagation is subjected to fading on both large-scales and small-scales that impair the quality and reliability of data link transmission. This has implications in many military applications. An example is the performance of communications links and unmanned aerial vehicle radio links when the ground forces are operating in foliage environments. The purpose of this research is to evaluate some simple models for propagation of radio waves in foliage using an electromagnetic field simulation application. The three dimensional (3D) electromagnetic field simulation application, CST Studio Suite, was used in the modeling and simulation process. Specifically, the CST Microwave Studio module was used to model the forest using dielectric blocks. Various combinations of forest dimensions, material dielectric parameters and antenna placements were simulated to obtain propagation models of radio waves in foliage environment. The simulation models are compared to three empirical models presented in the literature for propagation in foliage environment. Using the simulation model, we examined the coverage diagram for a transmitter antenna immersed in foliage. The results show that the proposed simulation models provide a rough approximation to radiowave propagation in an actual rainforest environment. Based on the simulated results, the path loss in foliage is affected by the forest's electrical characteristics, the height of the transmitter and the height of receiver.