Calculation of coupling factor for kHz-band wireless power transfer system using numerical human models

We have calculated the induced electric field strength in various human models exposed to wireless power transfer (WPT) system operating in kHz-band frequencies, and investigated the distance characteristics of coupling factor. The coupling factor is a factor which represents the relationship between induced electric field in the human model and incident magnetic field strength. The numerical results were indicated that the internal electric field strength of the 3-year child model in the vicinity of the WPT system is larger than the adult models and, in consequence, the coupling factor should be determined from the child model when the distance from the WPT systems is less than 0.5 m.