Equivalent circuit of signal line with magnetic layer

Abstract

A system of conductors having arbitrary permeability is analyzed through the generation of an inductance matrix that includes magnetic effects. This formulation, which makes use of both a magnetic scalar potential and preexisting inductance calculation algorithms based on vector potential, directly generates an equivalent circuit suitable for subsequent circuit analysis. The approach is applied to a two-dimensional signal line situated above a ground plane and composed of three conducting layers, the middle one being magnetic. Such lines find application in computer modules, where the use of conductor laminates may be required because of metallurgical considerations. Results show that at high frequency, current crowding into the upper layer gives rise to a significant increase in signal line resistance.