地铁高频电磁辐射的安全评估

为有效评估B型地铁乘客信息系统天线(Passenger information system,PIS)对司机室高频电磁辐射的安全性,设计PIS系统所用的5.8 GHz八木天线和司机人体模型,利用三维电磁仿真软件构建在PIS系统天线辐射下的地铁司机室高频电磁环境模型,数值模拟天线在不同输入功率条件下对地铁司机人体模型的高频电磁辐射影响。仿真结果表明,当天线的输入功率达到最大值50 W时,人体模型的比吸收率最大值0.63 W/kg,低于国际非电离辐射委员会(International Commission on Non-Ionizing Radiation Protection,ICNIRP)制定的职业电磁暴露基本限值10 W/kg;电场强度最大值为72.37 V/m,低于ICNIRP职业电磁暴露参考限值137 V/m;磁场强度最大值为0.74 A/m,高于ICNIRP职业电磁暴露参考限值0.36 A/m。当天线的输入功率降为10 W时,磁场强度最大值降为0.33 A/m,低于参考限值。因此,为了避免此高频电磁辐射对司机造成健康危害,地铁实际运行时,需要保证天线的输入功率低于10 W,使司机处于安全辐射范围内。

Safety evaluation of high frequency electromagnetic radiation in subway train

In order to effectively evaluate the safety in high frequency electromagnetic environment radiated by antenna of passenger information system (PIS) of subway train, the 5.8 GHz frequency Yagi-antenna and the human body model was designed. By using the three-dimensional electromagnetic simulation software, the high frequency electromagnetic environment model of the driver's cab of B-type subway train under the electromagnetic exposure of antenna was established while the occupational electromagnetic exposure of subway train driver was simulated. The results showed that when the input power of the antenna reached its maximum value of 50 W, compared with the limit values for electromagnetic occupational exposure constituted by International Commission on Non-Ionizing Radiation Protection (ICNIRP), the specific absorption rate of human body model was 0.63 mW/kg, which was lower than the basic limitation 10 W/kg; the strength of electric field was 72.37 V/m, which was lower than the reference limitation 137 W/kg; the intensity of magnetic field was 0.72 A/m, which was higher than the reference limitation 0.36 A/m. The intensity of magnetic field would be 0.33 A/m, which was lower than the reference limitation when antenna's input power was 10 W. It demonstrates that in such electromagnetic environment, the high frequency electromagnetic radiation in driver's cab would be harmful to subway train driver's health. Therefore, the input power of antenna should be lower than 10 W to ensure that the driver is in the safety electromagnetic exposure environment.