Using shadow lines to assure accurate signal return current in electrical package analysis codes

In moment-method codes, accurate representation of signal retum current usually requires that the basis function in the signal line be projected into the reference planes; this way the retum current can closely follow the same path as the signal line. A technique is described that efficiently assures highly accurate return current without the need for such projection. Examples from inductive and full wave modeling of appropriate StruCNreS are presented and discussed.