A Calibration Method for Spatial Resolution of Magnetic Probes Using a TEM Cell-Excited Slotted Rectangular Waveguide in Evanescent Mode

The spatial resolution of near-field magnetic probes is a crucial performance metric for conducting spatial field measurements in practical applications. However, the commonly adopted approaches for determining the spatial resolution of the probe face substantial ambiguity and limitations. Addressing this issue, a generalized definition of magnetic probe spatial resolution is proposed, which correlates directly with the effective size of the probe’s sensing front end. Following this definition, a novel calibration method is introduced, utilizing the evanescent field within a rectangular waveguide structure. This calibration method is implemented on the basis of a custom-designed transverse electromagnetic (TEM) cell, whose performance has been validated both in simulations and in experiments. The proposed method effectively mitigates uncertainties arising from the measurement position and field distribution, enabling a universal and accurate assessment of the spatial resolution of the probe. The efficacy of the calibration method is validated on a commercial magnetic probe. The comparative analysis demonstrates that the proposed calibration technique yields significantly improved accuracy compared to the existing method for determining the spatial resolution of the probe.