Ear-to-Ear Propagation Model Based on Geometrical Theory of Diffraction

Abstract

An ear-to-ear (E2E) propagation model based on geometrical theory of diffraction (GTD) is presented. The model uses the creeping wave loss along the geodesic paths that connect the ears. It is the first model to investigate which geodesic paths that link the ears. The model uses GTD expressions for a lossy dielectric material, which is a much better approximation of the human body than the perfect electric conductor approximation often used. The model is validated for the industrial, scientific, and medical band at 2.45 GHz. The model is valid at any frequency range as long as the propagation loss through the head is significantly higher than the propagation loss around the head. Similarly, the model could be used for other areas of the body. The comparison with simulations shows strong correlation. The antenna orientation and frequency sweeps were performed to further investigate the model. The sweeps change the radiation pattern of the antenna to utilize different paths around the head, but the model still correlates with the simulation. This validates the model's division of the E2E propagation into different geodesic paths around the head.