Evaluation of On-the-fly Scanning Effects on Complex Field Retrieval Using a Single Probe

The on-the-fly (OTF) scanning method has become a popular technique for rapidly characterizing electromagnetic (EM) near-fields. A recent advancement in OTF methods enables high-resolution retrieval of complex fields using a single probe. This work investigates the scanning effects occurring in combination with this technique. Firstly, Faraday’s law of induction is employed to study the behavior of moving conductors in dynamic EM fields. Theoretical analysis reveals three distinct dependencies of the probe signal: frequency, probe movement, and the spatial distribution of the complex field. Subsequently, the scanning effects are numerically evaluated on a realistic microstrip line (MSL) structure exhibiting a dynamic field variation exceeding 70 dB. The results demonstrate that OTF scanning can achieve an accuracy surpassing 99.9% at any scanning speed below 10 m/s across the kHz to GHz range. In this regime, the primary source of OTF measurement error is the field magnitude distribution, which is largely independent of frequency. Finally, the MSL is measured at 100 MHz using a near-field scanner based on an industry robot with a maximum movement speed of 0.36 m/s. Compared to the OTF scanning effects, position tracing errors and signal acquisition accuracy have a more significant influence on the measurement. This highlights the efficiency and practical applicability of the single probe OTF scanning technique.