29/04/2013
Assessing Human Exposure to Electromagnetic Fields From Wireless Power Transmission Systems
Andreas Christ, Mark Douglas, Jagadish Nadakuduti, and Niels Kuster, Proceedings of the IEEE , Volume 101, Issue 6, pp. 1482-1493, June 2013, online March 13, 2013
Wireless power transmission (WPT) systems transmit energy by means of an electromagnetic field that has strongly reactive components. The field strengths close to the transmitters can exceed the reference levels posed by the safety guidelines and can pose potential direct health hazards to persons in the environment of the WPT, as well as indirect risks via interference with medical implants. In this paper, the safety guidelines and the fundamental mechanisms of coupling of the human body with the electromagnetic near-fields of WPT are reviewed, and methodologies and instrumentation for the demonstration of the safety of such systems operating at 100 kHz – 50 MHz are discussed. The advantages and shortcomings of state-of-the-art numerical and experimental techniques in compliance and safety testing are discussed and applied to a generic WPT operating at 8 MHz. Recommendations for future research to define scientifically sound product standards for demonstrating the safety of WPT include:
- the extension of safety guidelines for coverage of individuals with medical implants
- computationally more efficient full-wave solvers for dosimetric simulations in the frequency ranges used for WPT
- higher quality human models that cover a broader range of different population groups
- improved models of nervous system tissues for the assessment of the stimulation threshold
- experimental dosimetric methods for the different frequency ranges used for WPT
- practical procedures to demonstrate safety of specific WPT