Numerical Exposure Assessment Method for Low Frequency Range and Application to Wireless Power Transfer.

Area of Science:

• Computational electromagnetics
• Bioelectromagnetics
• Numerical modeling

Background:

• Assessing human exposure to low-frequency electromagnetic fields is crucial for safety.
• Existing methods may lack accuracy for complex, non-uniform fields.
• Accurate dosimetry is needed for emerging technologies like wireless power transfer.

Purpose of the Study:

• To present a novel numerical exposure assessment method for quasi-static electromagnetic analysis.
• To compute induced electric fields and current densities in realistic human voxel models.
• To evaluate compliance with established safety guidelines for low-frequency exposure.

Main Methods:

• Utilized a scattered field finite-difference time-domain (FDTD) algorithm combined with quasi-static approximation.
• Applied the method to an anatomically realistic human voxel model.
• Validated the approach using a dielectric sphere model exposed to a magnetic dipole source.

Main Results:

• Demonstrated excellent agreement between the proposed method and theoretical solutions for validation.
• Calculated electric fields, current densities, and specific absorption rates in human head and body models.
• Quantified exposure levels from a 150-kHz wireless power transfer system for cell phone charging.

Conclusions:

• The proposed FDTD-based numerical method is effective for quasi-static electromagnetic exposure assessment.
• The method provides accurate estimations of induced fields and currents in human models.
• Results indicate compliance with International Commission on Non-Ionizing Radiation Protection (ICNIRP) and IEEE safety guidelines for the tested system.