A Novel Dipole Equivalence Method With Decoupled Amplitude and Position Searching for Near-Field EMI Identification

This article introduces a novel approach to construct dipole equivalence models based on near-field measurements, aiming to improve the source localization toward the analysis of electromagnetic interference in the near-field region among circuit boards. In contrast to conventional methods that simultaneously optimize dipole amplitudes and positions, the proposed method decouples these tasks by determining optimal dipole positions prior to dipole amplitude optimization. This strategy leverages the principle that current hotspots align with paths of minimum cumulative impedance, simplifying the search process. Through the decoupled search of dipole amplitudes and positions, the proposed method achieves efficient and accurate dipole equivalence construction with the knowledge of input/output port locations. Case studies on two-port/four-port microstrip line boards and practical mixing circuit boards are demonstrated. It is proved that the proposed method significantly reduces the computational time by more than seven times while improving the source reconstruction accuracy compared to the classical iterative approach.