Modeling and Simulation of Near-Earth Propagation in Presence of a Truncated Vegetation Layer

The far-field radiation from an infinitesimal electric dipole embedded inside a truncated vegetation layer above a dielectric ground plane is calculated in this paper. Through an application of the equivalence or Huygen's principle, a semi-exact solution for the received field at locations exterior to the vegetation layer is obtained by a surface-field integration technique in which the spatial domain of integration is over a plane containing the truncated face of the vegetation canopy. The numerical results are computed using stationary phase approximations and show improvement over those determined through an existing ray-tracing approach. Simulation results are also compared against measured data from controlled experiments carried out within a laboratory environment using a well-characterized scaled-replica of the propagation medium at a proportionally higher frequency. It is shown that ray-tracing provides accurate results at distant points from the vegetation truncation plane when the receiver height is large in terms of the wavelength but slightly underestimates the path loss when the receiver is close to the ground