Vermeeren Günter, Joseph Wout, Martens Luc
Department of Information Technology, iMinds/UGent, Ghent, Belgium.
Bioelectromagnetics. 2015 Oct;36(7):517-26. doi: 10.1002/bem.21935. Epub 2015 Sep 6.
The vast amount of studies on radiofrequency dosimetry deal with exposure due to mobile devices and base station antennas for cellular communication systems. This study investigates compliance of walkie-talkies to exposure guidelines established by the International Commission on Non-Ionizing Radiation Protection and the Federal Communications Committee. The generic walkie-talkie consisted of a helical antenna and a ground plane and was derived by reverse engineering of a commercial walkie-talkie. Measured and simulated values of antenna characteristics and electromagnetic near fields of the generic walkie-talkie were within 2% and 8%, respectively. We also validated normalized electromagnetic near fields of the generic walkie-talkie against a commercial device and observed a very good agreement (deviation <6%). We showed that peak localized specific absorption rate (SAR) induced in the oval flat phantom by the generic walkie-talkie is in agreement with four commercial devices if input power of the generic walkie-talkie is rescaled based on magnetic near field. Finally, we found that SAR of commercial devices is within current SAR limits for general public exposure for a worst-case duty cycle of 100%, that is, about 3 times and 6 times lower than the limit on the 1 g SAR (1.6 W/kg) and 10 g SAR (2 W/kg), respectively. But, an effective radiated power as specified by the Private Mobile Radio at 446 MHz (PMR 446) radio standard can cause localized SAR exceeding SAR limits for 1 g of tissue.
大量关于射频剂量学的研究涉及蜂窝通信系统中移动设备和基站天线造成的辐射。本研究调查了对讲机是否符合国际非电离辐射防护委员会和联邦通信委员会制定的辐射准则。通用对讲机由螺旋天线和接地平面组成，是通过对一款商用对讲机进行逆向工程得到的。通用对讲机天线特性和电磁近场的测量值与模拟值分别在2%和8%以内。我们还将通用对讲机的归一化电磁近场与一款商用设备进行了验证，观察到二者吻合度很高（偏差<6%）。我们表明，如果根据磁近场重新调整通用对讲机的输入功率，通用对讲机在椭圆形扁平人体模型中产生的峰值局部比吸收率（SAR）与四款商用设备一致。最后，我们发现，对于100%的最坏情况占空比，商用设备的SAR在当前公众暴露的SAR限值范围内，即分别比1 g SAR（1.6 W/kg）和10 g SAR（2 W/kg）的限值低约3倍和6倍。但是，446兆赫专用移动无线电（PMR 446）无线电标准规定的有效辐射功率可能会导致局部SAR超过1 g组织的SAR限值。
