Striction and skin effects on the internal impedance value of flat conductors

A frequency domain analysis is used to derive closed formulas giving the internal impedance of a rectangular, flat, nonperfectly conducting solid conductor modeling a ground plane. The approach takes into account the skin effect due to the finite conductivity of the ground plane and the increase of the impedance due to the confinement of the current lines at the contact points, called the striction effect. The computed results show that, in certain situations and within the frequency range of interest for the electromagnetic interference and compatibility community, the internal impedance calculated can no longer be neglected with respect to the external impedance when return conductors are located very near the ground plane