Study of mobile phone radiation inside metallic elevator

Abstract

Due to limited space, high-rise buildings are necessity in Hong Kong, and elevators are commonly installed for daily use. With the advancement of wireless communication technology, mobile devices such as PDA and mobile phones are frequently used in the elevator. In general, elevator is a rectangular stainless steel enclosure with several facades for the fours walls, floor and ceiling commonly constructed with metallic materials, glass or wood. Therefore, there could be resonance effect inside the metallic enclosure because of multiple reflections of electromagnetic field by the internal metallic materials of the elevator. The magnitude of electromagnetic field by the mobile devices is directly related to SAR (Specific Absorption Rate); and this could be considerably increased at certain locations due to the resonance effect. The increase in the electromagnetic field is a direct safety concern of human exposure to radio frequency. In my project, the resonance effect inside a metallic enclosure is examined; both simulation and experimental measurement inside an elevator have been carried out. The results summarize the situation of using mobile phone inside an elevator showing that number of people in the elevator (i.e. dielectric loading), dimensions and structure of the elevator affect the electromagnetic radiation significantly.