Full-Wave Electromagnetic Model Simulations of <italic>P</italic>-Band Radio Signal Propagation Through Forest Using the Fast Hybrid Method

Abstract

This article presents an analysis of P-band radio signal propagation through forest based on 3D Numerical Method of Maxwell's equations (NMM3D). The simulation domain of the forested region covers an area of 35.8 × 35.8 m2 that includes 112–121 coniferous trees with a height in the range of 8–16 m. The modeled trees have primary and secondary branches to account for their impact on scattering and attenuation at P-band. The fast hybrid method (FHM) has been successfully developed to complete the NMM3D full wave simulations of trees with efficient use of CPU time and memory. The accuracy of the proposed FHM model is validated by comparing scattered fields to that of FEKO for the case with nine trees. To account for the seasonal variation of water content in trees and hence dielectric constant, the wave scattering model is applied to a range of dielectric constants. Analysis of the P-band signal propagation is performed by computing the average loss and correlation of the transmission fields. The results show that the transmissivities are about 0.9 for winter conditions (low dielectric constant) and about 0.7 for summer conditions (high dielectric constant). Simulations with randomly positioned trees (off the periodic grid) demonstrate that the transmissivity shows a maximum variation of 4.3% relative to the nonrandomly positioned trees. The correlation analysis of P-band radio signals with two different dielectric constants indicates a high correlation amplitude above 0.89 and a phase change of less than 6°. A sensitivity analysis is carried out for a range of tree heights and trunk radii.

Keywords

• Electromagnetic modeling
• electromagnetic scattering
• full-wave simulations
• hybrid method
• Maxwell equations 3-D
• random media