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Conditions and Limits of Calibration-Free Magnetic-Field Measurement: A Minimal Model with In Situ Augmented-Reality
1Faculty of Engineering, Tohoku Institute of Technology, Yagiyamakasumi-cho, Taihaku-ku, Sendai 982-8577, Japan.
Sensors (Basel, Switzerland)
|August 13, 2026
Summary
This study introduces a calibration-free method for characterizing magnetic fields in wireless power transfer (WPT) systems. The technique simplifies measurements by analytically determining probe parameters, enabling practical 3D magnetic-field mapping.
Area of Science:
- Electromagnetics
- Wireless Power Transfer
Background:
- Accurate magnetic-field characterization is crucial for wireless power transfer (WPT) system evaluation.
- Traditional near-field measurement methods necessitate complex, setup-specific probe calibration.
Purpose of the Study:
- To propose a novel calibration-free framework for magnetic-field characterization in WPT systems.
- To simplify experimental procedures and enhance the practicality of magnetic-field measurements.
Main Methods:
- Development of a minimal small-loop magnetic-field probe model derived from Faraday's law.
- Analytical determination of the voltage-to-magnetic-field conversion coefficient using probe geometry and operating frequency.
- Validation through comparison with analytical models, Bessel-function-based models, and full-wave simulations.
Main Results:
- The proposed analytical model provides a calibration-free approach to magnetic-field measurement.
- Full-wave simulations suggest the loop circumference should be within approximately 0.1λ.
- Experimental validation at 13.56 MHz confirmed the method's efficacy in a WPT setup.
Conclusions:
- The calibration-free framework significantly simplifies magnetic-field characterization for WPT systems.
- Integration with three-axis measurement and augmented-reality (AR) visualization enables practical 3D magnetic-field mapping.
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