Compact metasurface track-side PIS antenna-based occupational electromagnetic exposure research of inspectors in the metro tunnel.

INTRODUCTION: With the advancement of Smart Urban Rail construction, the electromagnetic environment has become increasingly complex inside metro tunnels. Track-side inspectors may experience occupational radio-frequency (RF) exposure when conducting professional inspections in such a closed electromagnetic environment. METHODS: In order to analyze the occupational electromagnetic exposure dose absorbed by the track-side inspectors,and explore a method to reduce the influence of RF electromagnetic radiation. We propose a compact metasurface track-side passenger information system (PIS) antenna at first, and verify its good radiation performance. Then we compare the electromagnetic exposure metrics in the track-side inspectors human model when they are exposed to the conventional track-side PIS antenna and the proposed track-side PIS antenna at 5.8 GHz. RESULTS: The simulation results show that, the peak local specific absorption rate (SAR) is reduced by at least 39.83% in the trunk, skull, brain, heart, liver, and testes after the antenna is miniaturized by 53%. DISCUSSION: The findings indicate that the proposed track-side PIS antenna can reduce the external radiation energy, thereby reducing its impact on the surrounding environment. This research provides a theoretical analysis for occupational RF exposure safety of track-side inspectors and offers a dosimetry reference for antenna design in metro tunnel communication systems.