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In this article, we present a phaseless source reconstruction method based on dynamic differential evolution (DDE) combined with the least square and regularization for effectively constructing the equivalent dipoles to represent the real electromagnetic interference (EMI) sources, which enables the accurate reconstruction of near fields. The conventional DDE method is sensitive to the initial values of dipole moments, and the improper initialization may lead to the failure of its convergence. To avoid this, the proposed method employs least square (LSQ) to predict the dipole moment levels during initialization. This eliminates the need of multiple attempts to determine the appropriate range of dipole moments and thus saves the computation time. Moreover, LSQ is embedded in each iteration of DDE to further manipulate the dipole moments. The effectiveness and accuracy of the proposed method are verified through both simulation and experiment. This article offers a new and more reliable alternative for accurately reconstructing the near fields of EMI sources.

A wideband $E_{\textit {z}}E_{x}$ probe covering the frequency range of 1.4–7.0 GHz is proposed through the integration of a strip line magic-T. By combining a Marchand balun with its complementary structure, the magic-T achieves a wide working frequency band. The magic-T can effectively streamline complex data processing, enabling the proposed probe to offer a flexible instrument selection and achieve high measurement efficiency. A new calibration kit is further developed for the proposed probe. It effectively addresses the challenges associated with the asymmetry and probe movement commonly encountered in traditional probe calibration. A prototype of the probe is fabricated and measured. The results demonstrate a wide 1:5 working band, over 23 dB unwanted field suppression, and a good isotropy.

This article presents a novel design of an ${E}_{z}$ probe with a high spatial resolution. The key factors that have significant impact on spatial resolution are analyzed, and the optimal design for achieving a high spatial resolution is showcased. By strategically reducing the effective lengths of the probe in ${x}$ or ${y}$ -directions, remarkable spatial resolution is achieved. The proposed probe is cost-effective as it is fabricated on a four-layer printed circuit board (PCB) while exhibits more stable performance. To further improve the spatial resolution and address limitations in PCB fabrication, a blind-hole structure is implemented. Operating in a frequency band of up to 6 GHz, the probe demonstrates outstanding rejection of unwanted fields across a broad spectrum. Simulation and measurement results verify the exceptional performance of the proposed probe.

In this article, a compact partial element equivalent circuit (c-PEEC) model is presented for characterizing the electromagnetic (EM) problems with finite-sized piecewise homogeneous dielectrics. Unlike in conventional PEEC models where dielectrics are described by massive subcircuits, the proposed c-PEEC model addresses the composite conductor-dielectric problems via circuit elements resident on conductors only. Novel null-field boundary integral equations (n-BIEs) are formulated based on the surface equivalent principle and quasi-static assumption. The elimination of the magnetic field-related equivalent sources avoids the low-frequency breakdown problem caused by the weak EM coupling at low frequencies and improves the accuracy by inhibiting the numerical errors in discretizing magnetic sources. The computational cost is significantly reduced compared with the conventional models. Furthermore, the concise configuration of the c-PEEC model extends the model-order reduction (MOR) algorithms for fundamental homogeneous models to heterogeneous integration. Three numerical examples including a resonator, a radio frequency (RF) embedded passive circuit, and an interconnection problem, are studied to validate the stability, efficiency, and accuracy of the c-PEEC model. A micro-modeling circuit is obtained from the c-PEEC model to demonstrate its compatibility with the MOR algorithms.