Analysis of Factors Influencing High-Frequency Transfer Impedance in Surface Current Probe

Transfer impedance is a critical parameter for surface current probes. Due to the influence of the probe configuration and magnetic core material characteristics, the transfer impedance exhibits susceptibility to abrupt variations and oscillations within the hundred-megahertz frequency range. This study employs electromagnetic simulation to analyze the effects of core material properties, coil winding parameters, and enclosure structural clearance on the probe's transfer impedance characteristics. The findings reveal three optimization strategies for probe transfer impedance across the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1 \text{MHz}-500 \text{MHz}$</tex> spectrum: selection of magnetic cores with enhanced initial permeability, rational determination of coil turns and inter-winding spacing, and controlled adjustment of ferrite toroid-to-enclosure wall clearance. These results above provide valuable guidance for the development of surface current probes.