Modeling Site Specific Urban Propagation Using A Variable Terrain Radiowave Parabolic Equation - Vertical Plane Launch (VTRPE-VPL) Hybrid Technique

The development of efficient algorithms for calculating propagation loss in site specific urban environments has been an active area of research for many years. This dissertation demonstrates that, for particular scenarios, a hybrid approach that combines the Variable Terrain Radiowave Parabolic Equation (VTRPE) and Vertical Plane Launch (VPL) models can be used to produce accurate results for a downrange region of interest. The hybrid approach consists of leveraging the 2-D parabolic equation method in the initial propagation region, where backscatter and out of plane energy can be neglected, then transitioning to the more computationally intensive 3-D ray launching method for the domain closer to the receiver of interest. The geometry we are concerned with is a transmitter fixed high above the average building height, with receivers located downrange near ground level. The scenario for this study includes several building structures with flat walls and roofs, superimposed on a flat ground. This research investigates the performance of the VTRPE model in an urban landscape. This study also assesses the impact of the definition of the dielectric properties of the lower boundary of the calculation domain, which includes the ground and city buildings. Finally, this dissertation demonstrates the viability of the proposed VTRPE-VPL hybrid technique via model simulations of radio frequency propagation over an urban topography