Prediction of Crosstalk Involving Twisted Pairs of Wires-Part I: A Transmission-Line Model for Twisted-Wire Pairs

A transmission line model for predicting electromagnetic coupling (crosstalk) involving twisted-wire pairs (TWP) is developed. The twisted pair is modeled as a cascade of loops consisting of uniform two-wire sections with abrupt interchanges of wire positions at the ends of each loop. Experimental results are obtained for the coupling between a single wire above ground and a twisted pair above ground. The experimental correlation with the model predictions indicates that the simulation model is typically accurate within 3 dB for frequencies such that the total line length is less than 1/ 10 of a wavelength. For higher frequencies, the model tracks the experimental results quite well although the prediction error is somewhat larger.