Analysis of the interaction between a layered spherical human head model and a helical dipole antenna

The interaction between a three-layer spherical head model and a helical dipole antenna is described by applying the hybrid method of Green´s functions and auxiliary sources (Green/MAS). The main purpose of the paper is to provide a reliable tool for the solution of certain canonical problems pertaining to the dosimetric evaluation of potential health hazards in mobile telecommunications. As the analysis presented has a semi-analytical character, it can be used for benchmarking of purely numerical codes applied to the solution of more realistic geometries. Furthermore, it can give rough estimates of all the electromagnetic parameters of interest. The head is modeled by a three-layer lossy dielectric sphere whose dyadic Green´s function is calculated. The antenna is replaced by a distribution of elementary dipole sources lying along the curved axis of the helical wire and the feeding gap. Appropriate boundary conditions are applied on the surface of the antenna leading to a linear system of equations. By solving the system, the unknown dipole moments are determined. Subsequently, the electric field at any point in space (including the interior of the head and the far field) as well as other parameters of interest such as the current on the antenna surface, the input impedance etc. can be easily calculated