On the combined effect of random nonuniformity and deformation of twisting on the radiated immunity of twisted-wire pairs

This work deals with radiated immunity of twisted-wire pairs (TWP) having random nonuniform twisting. This category includes special TWPs with intentional nonuniformity, developed in recent patents, as well as traditional TWPs where nonuniformity results from unintentional random imperfections involved in the manufacturing process. By resorting to a recently proposed stochastic-process representation of the twist pitch, two geometrical properties of twisting are investigated, that is, nonuniformity and deformation. Radiated immunity is analyzed by means of repeated-run simulations aimed at predicting the common-mode and differential-mode voltages induced across the terminal TWP loads by an external plane-wave electromagnetic field. It is shown that nonuniformity actually decreases radiated immunity of TWPs, however, this effect is considerable only if nonuniformity is combined with substantial deformation.