Introduction to field tracing

Field tracing is the generalization of ray tracing and enables electromagnetic system modeling. Harmonic fields are traced through the optical system instead of ray bundles. This allows the smooth combination of different modeling techniques in different subdomains of the system, e.g. to use the rigorous spectrum-of-plane-wave operator for homogeneous media, geometrical optics to trace through a lens and finite element methods to include the effect of some scatterer. All modeling techniques have to be formulated for vectorial harmonic fields. The paper introduces the basic concepts of field tracing and derives the corresponding operator equations. Propagation in homogeneous media is of special concern in field tracing to interconnect the modeling in different subdomains of the system. A new concept for a smart propagation algorithm is presented. Because of the success of geometrical optics in ray tracing, it is reasonable to consider its application in field tracing. In this paper we discuss generalizations of geometrical optics that have been enforced by field tracing. Although the basic field tracing equations are formulated for vectorial harmonic fields, general fields can be treated by suitable decompositions into sets of harmonic modes.