Microwave Propagation Modeling and Measurement of Scattering and Absorption Inside a Canopy Using the FDTD Technique

This paper proposes a novel method aimed at modeling microwave scattering and absorption inside a canopy, arising from the interaction with the individual components of the vegetation specimen, starting from primary models for leaves, trunk and branches. The method is based on the finite-difference time-domain (FDTD) technique to predict the 3-dimensional re-radiation fields of the entire tree, by combining the effects of the single elements forming the tree. Appropriate measurements performed in an anechoic chamber environment at microwave frequencies, i.e. 20 GHz, and in the forward scattering region, provided both model validation and a deeper insight into the problem. The model is shown to be capable of predicting the near-field radiated signal and the radar cross section (RCS). The predictions yielded good agreement with measurements and provides a good basis for a planning model capable of accounting for single trees in the radio path.