Non-Uniform Magnetic Field Exposure Assessment Using Coupling Factors Based on 3-D Anatomical Human Model

Coupling factors are calculated in order to facilitate non-uniform magnetic field exposure assessment. Coupling factors take into account the characteristics of a localized non-uniform field source, whereas reference levels in electromagnetic field safety guidelines only consider uniform field exposures. The calculations are performed using several different equivalent human models including simplified homogeneous models and a complex anatomical model. Three types of non-uniform sources are considered; a circular coil in a vertical plane, a circular coil in a horizontal plane, and a straight wire in a horizontal plane. For modeling and quasi-static electromagnetic simulation of the complex anatomical human model, Sim4Life software was used, which applies finite-element method to graded voxel meshes. The dependence of coupling factor values on the various parameters including source type, distance between source and human model, coil radius, and type of the equivalent human model used is analyzed. Also, separate definitions of coupling factors given in various IEC standards are analyzed and their differences in practical applications are investigated.