Natural Resonances of a Lossy Conductor-backed SLAB Excited by a Non-planar Incident Field

Abstract

The impulsive transient response of a conductor-backed dielectric slab to line-source illumination is considered. After compensating for the transient effects of the two-dimensional source, the scattered field is characterized as a natural mode series. The natural frequencies are extracted using the E-pulse technique, and are shown to approach the natural frequencies excited by plane-wave illumination as the source and observer heights approach infinity. At lower source and observer heights, the behavior of the natural frequency response is examined, and the trajectories of the natural frequencies in the complex plane as a function of these heights are established. These results should prove useful for material characterization using the E-pulse technique with a source having a non-planar wavefront.