Analytical study of radiowave absorption by the brain and the eyes in an eccentric spheres model of the human head

Biological effects of radio-frequency and microwave radiation draw strong interest nowadays. Special attention is paid to the absorption of electromagnetic (EM) radiation by the human head because of the widespread use of handheld transceivers for wireless communications. Although numerical techniques can deal with more complex geometries, analytical solutions are indispensable as benchmarks. So far the most complex head model that has been used by analytical techniques is the layered eccentric spheres model of Skaropoulos et al. (1996), which comprises a stratified spherical brain tissue core eccentrically placed within a stratified spherical skull. Eccentric spheres models have also been used within the framework of EEG and MEG research. The head model used herein consists of a stratified spherical skull and three layered spherical inhomogeneities representing the brain and the eyes. The absorption of EM radiation as well as the distribution of the specific absorption rate (SAR) are calculated by use of the indirect mode matching technique (IMM). Excitation is provided either by a plane EM-wave or by an electric dipole, placed near the head. Interest is focused on frequencies used by cellular phones.