Thin Film Magnetic Sensor for Magnetic Near-Field Measurement in Wireless Power Transfer System

In this study, we employed a high-frequency-driven thin-film magnetic sensor to precisely measure the magnetic near field with enhanced spatial resolution, a challenge often faced by conventional loop antennas. Our study introduced an innovative approach utilizing this magnetic sensor to assess the magnetic near field in wireless power transfer systems, comparing its performance against that of a loop antenna. Our findings demonstrate that the magnetic sensor achieves its peak signal-to-noise ratio at a DC bias field of 4.7 Oe and carrier frequency of 0.5 GHz, boasting a detection limit for magnetic fields of ~0.4 A/m. Moreover, the magnetic field trend measured by the magnetic sensor closely aligns with simulation results, exhibiting sharper changes around the center compared to the loop antenna. These results highlight the superior sensitivity and spatial resolution of the magnetic sensor over conventional loop antennas. By enhancing the reliability of electronic systems across diverse applications, these sensors pave the way for advanced EMI/EMC evaluation techniques. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.