A strictly causal numerical study of the pulsed operation of a weakly dispersive, leaky wave (LW) antenna is presented. The intricacies at the forefront of the electromagnetic (EM) field radiated from a gap-fed slot in a perfectly electrically conducting (PEC) sheet are evidenced for the first time. The radical effect of a free-space gap separating the PEC sheet from the dielectric half-space into which the slot radiates is demonstrated, thus providing time-domain (TD) arguments for the effectiveness of this essential element of leaky-lens antennas (LLAs). The response of the gapped structure to an excitation consisting of pulse trains is evaluated. The discussed results pave the way toward building a genuine TD counterpart of the LW radiation from gap-fed slots. Furthermore, they are conditional to understanding the transients occurring in between intervals when a steady-state, time-harmonic (TH) operation can be assumed, an extremely relevant ingredient to implementing highly complex modulations in carrier-based, wireless transfer.

The late-time evaluation of electromagnetic (EM) field quantities yielded by convolution integrals that combine Green's functions available at discrete time samples and strictly causal excitations is critically revisited. A typical situation is used for tracing the causes of the divergent late-time behavior that is often experienced. A framework combining a suitable integral partitioning with a polynomial approximation is shown to effectively guarantee the integrals' convergence. The formulation is validated via numerical experiments evidencing its accuracy and computational efficacy. The method is amenable to be used in a wide range of problems requiring the late-time evaluation of convolution integrals of the indicated type.

The electric-line-source excited, pulsed electromagnetic (EM) field response on the surface of a highly contrasting thin sheet with dielectric and conductive properties is studied analytically in the time domain (TD) with the aid of the Cagniard-De Hoop technique. Closed-form TD expressions reveal anomalous highly oscillatory EM transients propagated over the surface of the layer. Illustrative numerical examples demonstrate the EM surface phenomenon.

The amplitude-modulated, cosine powerexponential (PE) and windowed-power (WP) pulses are discussed, by insisting on their time-domain normalization. Illustrative examples of signatures and their correspondent frequency-domain behavior are given. These examples compellingly demonstrate the possibility to replace non-causal pulses of prevalent use by causal, or even time-windowed, pulses with closely resembling signatures.

The pulsed EM-field signal transfer between two co-planar small-loop antennas located on a half-space with dielectric and conductive properties is analyzed analytically with the help of the Cagniard-DeHoop technique and the Schouten-Van der Pol theorem. The analysis yields a closed-form time-domain expression for the open-circuit voltage induced across the ports of the receiving antenna. Limiting cases considering the mutual coupling between two loops placed in free-space and on a dielectric half-space are discussed. The obtained results are validated using analytical expressions for the special cases and with the aid of a 3-D EM computational tool.