Wave-front Behaviour of the Pulsed EM Field – Complexity and Implications

The pulsed electromagnetic (EM) field radiated by a gap-fed, long slot in a perfectly conducting thin sheet located in between dielectric and free-space subdomains is examined. A phenomenological interpretation of the so-called head wave (HW) constituent is proposed, this fostering the understanding of the complex EM behaviour at, and immediately behind, the HW wave-front. The EM field is also examined numerically for identifying features that may lead the way towards inferring a causal counterpart of the leaky-wave propagation.