Toward a More Realistic Characterization of Hand-Assembled Wire Bundles: Geometrical Modeling and EMC Prediction

In this paper, a systematic approach for electromagnetic compatibility (EMC) modelling of hand-assembled, complex cable bundles is presented. The first part of the article focuses on bundles laid out above a ground plane, with layout approximately parallel to the reference ground. In order to generate smooth and physics-based trajectories, polynomial curves are used to represent the conductors in the bundle. A suitable process for the generation of bundle samples is developed, which allows for controlling the degree of randomness and avoiding conductors overlapping. Parametric representation of more general bundle structures with arbitrary orientation is then addressed, and the modeling approach is extended to more complex bundle structures, such as bundles involving twisted-wire pairs. To assess the ability of Transmission Line (TL) theory to deal with complex and locally highly non-uniform bundle shapes, a fictitious bundle trajectory shaped as a trefoil knot is introduced. All the generated bundle geometries are used in combination with TL-based EMC models in order to predict the disturbances induced in the bundle terminal units due to crosstalk or coupling with external electromagnetic fields. Prediction accuracy is assessed by comparison versus full-wave electromagnetic simulation of the same bundle structures. Suitable examples are presented to show the high numerical efficiency and good accuracy of the proposed modeling approach, as well as the need for accurate and physics-based representation of the bundle geometry in order to achieve solid EMC prediction in a wide frequency range.