Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.
Sunohara T, Hirata A, Laakso I, Onishi T · 2014
View Original AbstractWireless charging systems operate at EMF levels thousands of times below current safety limits, but those limits may not protect against non-thermal biological effects.
Plain English Summary
Scientists tested how much electromagnetic energy people absorb from wireless phone charging pads at 140 kHz frequency. They found extremely low absorption levels - 72 nanowatts per kilogram at 1 watt power. This confirms wireless charging systems operate far below safety limits for human exposure.
Why This Matters
This study provides important baseline data for understanding EMF exposure from wireless charging technology, which is becoming ubiquitous in smartphones and electric vehicles. The science demonstrates that current wireless charging systems operate at power levels far below established safety thresholds. However, what this research doesn't address is whether these safety limits themselves are adequate. The reality is that safety guidelines focus primarily on heating effects from EMF exposure, not the growing body of research showing biological effects at much lower, non-thermal levels. While this study suggests wireless charging poses minimal risk under current guidelines, it highlights the need for exposure standards that account for non-thermal biological effects, especially as wireless power transfer technology scales up for electric vehicle charging and other high-power applications.
Exposure Details
- SAR
- 0.000000072, 2 W/kg
- Electric Field
- 0.091, 18.9 V/m
Where This Falls on the Concern Scale
Study Details
This study investigates the specific absorption rate (SAR) and the in situ electric field in anatomically based human models for the magnetic field from an inductive wireless power transfer system developed on the basis of the specifications of the wireless power consortium.
The transfer system consists of two induction coils covered by magnetic sheets. Both the waiting and...
The results indicate that the peak value of the SAR averaged over a 10 g of tissue and that of the i...
Show BibTeX
@article{t_2014_analysis_of_in_situ_1347,
author = {Sunohara T and Hirata A and Laakso I and Onishi T},
title = {Analysis of in situ electric field and specific absorption rate in human models for wireless power transfer system with induction coupling.},
year = {2014},
url = {https://pubmed.ncbi.nlm.nih.gov/24936747/},
}