Characterization of Near-Field Coupling With Unshielded Star-Quad Cable Above a Ground Plane

A transmission-line model for characterizing near-field coupling with a star quad cable is improved, where it utilizes a pair of electric and magnetic dipole moments for reproducing the near field distributions. The induced common- and differential-mode currents at balanced terminals of the star-quad cable are predicted by using the transmission line theory. The obtained results are in good agreement with those generated by the commercial software FEKO. Further, we pay attention to such star-quad cables having four conductors arranged in a balanced geometry, providing immunity to an external coupling. It is shown that the star-quad cable has very good advantage in suppressing electromagnetic interferences, as compared to twisted-wire pair cables.