An Improved Spectral Probe Calibration for Near-Field to Far-Field Transformation

The near-field scanning technique is a potent tool for addressing electromagnetic interference (EMI) problems of which electric and magnetic probes are essential components in the near-field scanning systems. Hence, accurate probe calibration is crucial for precise field measurement. In this article, we present an enhanced probe calibration method in the spectral domain, tailored for near-field to far-field transformation. Unlike traditional spectral probe calibration, we introduce a new calibration factor (CF), enabling more precise far-field estimation of a device under test (DUT). The proposed method effectively supplements traditional calibration approach, particularly when high-accurate far-field prediction is required. Comparison reveals that the proposed method achieves smaller relative errors between the predicted and reference far-field results than traditional method. Moreover, it demonstrates salient robustness against noise. This method is validated through numerical and experimental examples, substantiating its great potential in EMI near-field scanning technique.