In high-density differential interconnects, reassigning differential pairs to connector contacts offers a free way to control interpair electromagnetic coupling without hardware modifications. This article derives the differential-mode (DM) inductance matrix (Ldm) from the per-unit-length inductance of shielded multiconductor bundles and proposes a systematic connector pairing optimization strategy. We adopt the maximum DM mutual inductance (|Mmaxdm|) as the core optimization metric and use a lumped circuit model with arbitrary terminations to verify its capacity to predict differential crosstalk. Simulated and measured SddXT curves of six pair configurations from 0.001–1 GHz are compared to validate the model accuracy. The analytical results match the measured crosstalk trends well over the full band, confirming that |Mmaxdm| reliably quantifies the interpair crosstalk levels for different pairing layouts. The method is first verified on a four-pair twisted-wire setup, where Ldm clearly differentiates the crosstalk performance across configurations. To test its practical scalability, it is further extended to a 27-pair harness with Y50EX aviation connectors. Relative to conventional pairing, the optimized scheme decreases |Mmaxdm| from 48.83 to 43.78 nH/m and suppresses high-frequency crosstalk by at least 6 dB. The proposed pairing optimization provides a low-cost, hardware-free approach to mitigate crosstalk in dense differential interconnect systems.
Current electromagnetic field (EMF) assessment standards for wireless power transfer (WPT) systems, such as IEC/IEEE 63184, apply different assessment procedures depending on device type and exposure scenario, but quantitative metrics for characterizing the spatial concentration of exposure remain limited. To complement existing procedures, this article proposes the local-to-whole-body exposure ratio (LWR), a simulation-based exposure index derived from the magnetic-field distribution within a segmented human body model. LWR is defined as the ratio of the magnetic-field exposure within the top 5% of the body volume to that within the entire body volume. Parametric simulations were performed using homogeneous adult and child body models at 85 kHz for electric vehicle (EV), forklift, and automated guided vehicle (AGV) WPT systems and at 6.78 MHz for a wireless charging mousepad. For the adult model, the LWR values were 10.46%, 30.43%, 31.68%, and 76.34% for the EV, forklift, AGV, and mousepad, respectively. Consistency analysis using the three-point spatial averaging method showed low error for the EV, forklift, and AGV cases but a substantially higher error for the mousepad, indicating that LWR effectively distinguishes broadly distributed and localized exposure patterns. The proposed LWR does not replace the basic restrictions or reference levels specified in existing standards, but provides quantitative support for selecting whole-body-oriented, local-oriented, or combined exposure assessment procedures in WPT EMF evaluations.
Local area network (LAN) wired communication systems are susceptible to external electromagnetic interference (EMI), which can propagate through conductive interconnections and affect network functionality. Accurate prediction of EMI propagation is challenging because the electromagnetic parameters of network components—such as scattering matrices and transmission matrices—are difficult to characterize in situ: dedicated test fixtures are required, and the measurement process would disrupt network operation. This article presents a physics-based prediction approach for EMI propagation in LAN-type wired networks. A Baum–Liu–Tesche-guided graph neural network is developed to predict port-level interference currents directly from network topology and excitation conditions, without requiring explicit electromagnetic parameters. To bridge the gap between simulation and practice, a measurement-driven sim-to-real transfer learning strategy is proposed, where a small experimental dataset collected from four canonical network topologies is used to adapt the simulation-trained model. Experimental results demonstrate accurate prediction of port-level interference currents. Validation on two network topologies unseen during transfer learning achieves a mean prediction error below 1 dB and a maximum error below 3 dB over the 1–40 MHz frequency range. Cross-scale evaluation further shows strong generalization from 10-node to 100-node networks, with prediction errors remaining within approximately 3 dB for network scales not included in training. The proposed method enables practical system-level EMI propagation prediction without explicit electromagnetic parameters, providing an efficient tool for electromagnetic compatibility assessment of LAN-type wired networks. Its current applicability is limited to linear propagation, single-cable-type interconnections without crosstalk, and single-frequency common-mode excitation.
Structural discontinuities at conductive gasket interfaces often dominate high-frequency electromagnetic leakage in electronic enclosures, while standardized methods mainly assess overall shielding performance. This article proposes a multiport measurement approach for the comparative characterization of conductive gasket interfaces under controlled assembly conditions. Using a custom eight-port fixture, nonaligned port pairs suppress direct transmission, so that off-diagonal S-parameters are primarily governed by seam-induced coupling. A leakage-coupling shielding effectiveness (LC-SE) metric is formulated as the reference-to-test power ratio on a selected channel under identical cover gaps. For the developed prototype, S81 is selected as the reporting channel via a geometry-dependent criterion to maximize leakage observability within a fixture-validated 0.1–6.0 GHz band. Extensive evaluations across nine gasket configurations, gap variations, and intentional local defects demonstrate high leakage sensitivity, assembly repeatability σ = 2.77 dB; expanded uncertainty of the mean U = 2.54 dB (k = 2), and limited land-level spatial discrimination. Furthermore, rank cross-check against a metal enclosure is consistent with of the LC-SE81 metric for interface ranking.
This article presents the first assessment of the electromagnetic field exposure from bidirectional wireless power transfer (WPT) for electric vehicle charging. A bidirectional inductive power transfer (BIPT) system was simulated by combining the SAE J2954 WPT2-class coil (7.7 kW) with an electrical circuit including H-bridge converters to enable grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes. The approach of considering H-bridge converters captures modifications in coil current and magnetic field (B-field) distribution that are not captured in conventional unidirectional inductive power transfer systems. The simultaneous operation of two adjacent BIPT systems in a realistic parking lot was also investigated to evaluate B-field superposition effects. Exposure levels at 85 kHz were calculated and compared against ICNIRP and IEEE exposure limits for three power flow combinations (G2V+G2V, G2V+V2G, V2G+V2G), both inside and outside the vehicles, at four heights corresponding to the ground, and the genitals, heart, and head levels of a typical adult and a 3-year-old child; outside the vehicle the B-field at these heights was investigated for two pedestrian postures: standing and lying on the ground. Results show higher B-field levels outside the vehicles, generally decreasing with height, with a maximum of 0.1 T at the ground level above the WPT coil. In the inter-vehicle region, B-field levels depended on the power flow combination, with a peak of 24 μT for G2V+V2G and V2G+V2G combinations. Notably, a constructive superposition effect was observed for the G2V+V2G combination, resulting in a local B-field increase at 0.25 m, with B-field values up to 91% higher than other combinations. The exposure at the typical height of a child was consistently higher than that of an adult. While compliance with ICNIRP and IEEE limits was observed both inside and outside the vehicles, noncompliance occurred directly beneath the chassis, above the WPT coil.
