SAR in children from exposure to wireless local area networks (WLAN)

Abstract

Finite-difference time-domain (FDTD) calculations have been performed at 2.4 GHz and 5 GHz using a voxel model of a sitting 10 year old child to investigate human exposure to the electromagnetic fields in schools produced by wireless local area networks (WLAN). This study presents whole-body and peak localized specific energy absorption rates (SAR) in the model resulting from both plane wave fields and fields produced by representative WLAN antennas positioned close to the body. In a worst case exposure configuration, the highest peak localized SAR was calculated in the head for a dipole antenna at 3 cm away from the face. This resulted in SAR values of 8.17 W kg−1 (2.4 GHz) and 5.22 W kg−1 (5 GHz) per W. For a typical Wi-Fi exposure scenario using an inverted F antenna operating at 100 mW, ∼34 cm away and a duty factor of 0.01, the maximum peak localized SAR was found to be 0.399 mW kg−1 in the torso. At 2.4 GHz, using a power of 100 mW, ∼34 cm away and a duty factor of 0.01, the highest localized SAR value in the head was calculated as 0.057 mW kg−1. This represents less than 0.01% of the SAR previously calculated in the head for a typical mobile phone exposure condition.