Generalized Ray Theory for Time-Domain Electromagnetic Fields in Horizontally Layered Media

Generalized-ray theory for time-domain electromagnetic fields in a horizontally layered medium is developed. It can be considered as the time-domain equivalent of the intensively studied Green´s function formulation in frequency domain. After introducing appropriate integral transformations and source-type field representations, the solution is written out in terms of generalized ray constituents whose space-time counterparts are constructed with the aid of the Cagniard-DeHoop technique. The formulation lays the foundation to rigorously study time-domain field behavior in numerous practical topologies where a stratified multilayer is involved, such as planar antennas and circuits, but also electromagnetic compatibility (EMC) and propagation problems. Illustrative numerical results are presented.