Study on Magnetic Probe Calibration in Near-field Measurement System for EMI Application

Near-field measurement, as an efficient method for studying the electromagnetic interference (EMI) problem, is becoming increasingly important. The calibration of the near-field probe is a critical part in the measurement procedure. This paper presents a fast and effective calibration method of magnetic probe. The factors that influence the calibration method is analyzed and discussed. Two kinds of calibration structures are designed and fabricated to determine the probe factor (PF) of two magnetic probes, which are horizontal magnetic field probe and vertical magnetic field probe, respectively. Moreover, PF is obtained through comparing the measurement data with the simulation data of the same calibration structure. Another sample is designed and fabricated to verify the obtained PF and the calibration method. The measurement results match simulation results well with the relative errors at the “large signal region” less than 20%, which indicates a good accuracy of the calibration method.