Analysis of Two-Media Structures Using Longitudinal Spectrum: Space, Surface, and Zenneck Waves

The longitudinal spectral expansion method is extended to simplify the electromagnetic field analysis in a two-media structure with and without ground plane. A nonconventional Riemann sheet is invoked that clarifies some important characteristics of the fields. For instance, it is straightforward to prove that in a two-media half-space, no surface wave exists for lossless media. However, if a medium is lossy, then a fast surface wave, known as a Zenneck surface wave (ZSW), exists that dominates within a limited radial distance.