A Conservative Model for Small Electric Field Sources in Analytical RF Exposure Assessments

This paper proposes a modelling approach for small electric-field (E-field) sources, e.g., capacitive power transmitters, that is conservative from a radiofrequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathbf{R F})$</tex> exposure standpoint. The conservatism of the proposed model is demonstrated via simulation, and an analytical approach for assessing RF exposure in a homogeneous flat phantom is presented. Results include maximum drive current levels for this phantom as a function of source dimension and separation distance. Future research will explore field enhancement effects due to the shape and orientation of the phantom as well as tissue heterogeneity. In addition to improving our understanding of the coupling effects between small E-field sources and human tissue, this research could lead to the development of analytical exemption levels to reduce the compliance burden of low energy sources, such as small capacitive chargers and active sensors.