A 3-D Model for Millimeter-Wave Propagation Through Vegetation Media Using Ray-Tracing

This communication proposes the 3-D extension of a ray-tracing-based model for radio wave propagation modeling in the presence of trees and vegetation areas. The original propagation model uses various point scatterers with specific radiation characteristics to describe the trees' electromagnetic behavior. To this extent, measurements intending to characterize the 3-D scattering profile of various small indoor tree specimens, including groups of trees, mimicking trees with varying thickness, were conducted in a controlled environment, at 60 GHz. Subsequently, the available experimental data were used to enhance the original point scatterer formulation and to develop its extension to 3-D simulation scenarios. Finally, the performance of the proposed 3-D model was assessed in a tree formation scenario against 3-D directional spectra measurement results obtained inside an anechoic chamber, at 18.8 and 60.6 GHz. These measurements were conducted in various locations inside the tree formation, and the transmitter was set at different positions and heights, to establish oblique, slant, and both oblique and slant signal incidences impinging at the air-to-vegetation interface.