title: Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches.
abstract: In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.
authors.affiliation: Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), 218 Gajeongno, Yuseong-gu, Daejeon, Korea.
authors.forename: Seon-Eui
authors.initials: SE
authors.lastname: Hong
authors.forename: Ae-Kyoung
authors.initials: AK
authors.lastname: Lee
authors.forename: Jong-Hwa
authors.initials: JH
authors.lastname: Kwon
authors.forename: Jeong-Ki
authors.initials: JK
authors.lastname: Pack
mesh_terms: D060733:Electromagnetic Radiation; D004781:Environmental Exposure; D006801:Humans; D008953:Models, Anatomic; D008962:Models, Theoretical; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*