Investigation of the assessment method for human exposure from a wireless power transfer system

Various types of wireless power transfer devices have been developed recently and active researches are ongoing in each country. In this paper, we investigated the limitations and difficulties in the exposure assessment for wireless power transfer devices, and proposed a new assessment method based on the correlation characteristics between SAR and external magnetic field. As a typical example, the exposure from a wireless mobile-phone charger were analyzed in detail, assessed for the basic restrictions and reference levels of ICNIRP, FCC and Korean guideline[1]-[3], and problems related to the exposure assessment were discussed. The correlation characteristics between SAR and external magnetic field of the wireless charger, on which the new method is based, are presented. The proposed method is quite reasonable and can get around the difficulties in the exposure assessment of wireless power transfer devices.