Advanced Modeling of Crosstalk Between an Unshielded Twisted Pair Cable and an Unshielded Wire Above a Ground Plane

This paper deals with the modeling issue of the near-field coupling of an unshielded twisted-wire pair on a nearby single wire. It introduces a discussion about the appropriate modeling method for predicting the induced current on the victim wire and proposes a cost-effective approach to deal with either ideal or nonideal twisted pair. A nonideal twisted pair consists of a twisted pair whose ends are left untwisted for connection to equipment. We show that the current distribution may follow a specific spatial distribution on the nearby wire. These coupling effects are evidenced through the analysis of an equivalent circuit under the low-frequency assumption. These behaviors are illustrated for the case of both an ideal twisted pair and a nonideal twisted pair. For the latter, the ideal bifilar helix may be modeled by a simple equivalent model bifilar cable.