Assessment of Incident Power Density on Spherical Head Model up to 100 GHz

Abstract

This article presents a technique for the accurate assessment of the spatially averaged incident power density (IPD) on a spherical human head model from 3.5 to 100 GHz. The spatially-averaged IPD is defined either by averaging components of the power density vector normal to an evaluation surface, or by averaging its norm. The electromagnetic exposure assessment is provided for a dipole antenna placed at a separation distance of 2–150 mm from the model. We compare the IPD averaged over a proposed spherical surface with differently positioned planar surfaces. Results show that, for appropriate settings of the ex- posure above 6 GHz, the IPD averaged on a spherical surface is up to 12% larger for the normal definition, while marginally lower for the norm definition. In the worst case scenario, the spatially averaged IPD on a spherical surface is up to about 30% larger regardless of the definition. Comparative analysis between the definitions of the IPD averaged on a spherical model demonstrates that the norm definition yields significantly larger values in the reactive near field at characteristic frequencies, whereby this difference is marginal out of the reactive near field.