Characterization of Electromagnetic Wave Coupling With a Twisted Bundle of Twisted Wire Pairs (TBTWPs) Above a Ground Plane

A multiconductor transmission line model is developed to characterize electromagnetic wave coupling with a twisted bundle of twisted wire pairs (TBTWPs) running above a ground plane. A set of parametric equations of each wire in each bundle is derived at first, together with its unit tangent vector defined analytically. Furthermore, its averaged per-unit-length parameters are determined according to the derived analytical equations, and the equivalent voltages for describing field-wire coupling are presented. The proposed model is employed for predicting both common mode and differential mode currents induced at different terminal loads of the TBTWP, where fire-side, end-fire, broad-side, and arbitrary electromagnetic wave incidences are investigated. The numerical results of our model are validated in comparison with that of the commercial software FEKO, with good agreement achieved between them. Furthermore, such TBTWP model can be extended for studying electromagnetic wave coupling with multiple TBTWPs employed in many cable systems.