Pulsed electromagnetic (EM) field signal transfer from a general EM source distribution to a transmission line (TL) is analyzed with the aid of Lorentz’s reciprocity theorem. In this fashion, the transient voltage induced by the impulsive EM source is expressed through the EM fields as radiated by the TL. These transmitted EM fields are expressed in closed form using an analytical procedure that resembles the Cagniard-DeHoop (CdH) technique. The validity of the proposed reciprocity-based methodology is verified with the aid of an alternative analytical solution describing the EM field signal transfer excited by an impulsive vertical electric dipole (VED). Illustrative numerical examples are presented.

The main result of Lovat et al. (2023) is put into context of previously published papers on the subject. Its correction is described.

An approximate computational model of an electromagnetic (EM) pulse excited thin-wire antenna is developed. The presented solution methodology is based on the Cagniard-deHoop method of moments (CdH-MoM) and Hallén's approximation of the thin-wire model. It is shown that the proposed time-domain (TD) solution leads to an inversion-free, efficient updating procedure that mitigates the marching-on-in-time accumulation error. An illustrative numerical example demonstrates the validity of the proposed model.

V.A unified description of the time-domain (TD) electromagnetic (EM) field coupling to a transmission line (TL) that is terminated by arbitrary linear time-invariant loads is presented. Closed-form expressions for the electric current induced in the loads are derived with the aid of the EM reciprocity theorem of the time-convolution type. The validity of the solution is demonstrated via illustrative numerical examples.

Pulsed electromagnetic (EM) scattering by short-wire and small-loop antennas loaded by time-varying (TV) loads is analyzed with the aid of time-domain (TD) compensation theorems. TD analytical expressions describing the change of back-scattered EM fields from dipole antennas due to their TV load are given. Illustrative numerical examples are presented.

This paper presents a systematic approach to derive physical bounds for passive systems, or equivalently for positive real (PR) functions, directly in the time-domain (TD). As a generic, canonical example we explore the TD dielectric response of a passive material. We will furthermore revisit the theoretical foundation regarding the Brendel-Bormann (BB) oscillator model which is reportedly very suitable for the modeling of thin metallic films in high-speed optoelectronic devices. To this end, an important result here is to re-establish the physical realizability of the BB model by showing that it represents a passive and causal system. The theory is based on Cauer's representation of an arbitrary PR function together with associated sum rules (moments of the measure) and exploits the unilateral Laplace transform to derive rigorous bounds on the TD response of a passive system. Similar bounds have recently been reported for more general casual systems with other a priori assumptions. To this end, it is important to note here that the existence of useful sum rules and related physical bounds rely heavily on an assumption about the PR functions having a low- or high-frequency asymptotic expansion at least of odd order 1. As a particular numerical example, we consider here the electric susceptibility of gold (Au) which is commonly modeled by well established Drude or BB models. Explicit physical bounds are given as well as an efficient fast-Fourier transform -based numerical procedure to compute the TD impulse response associated with the nonrational BB model.

An analytical approach to the analysis of electromagnetic (EM) reflection and transmission of a plane wave at a time-varying, high-dielectric thin layer is described. Closed-form expressions for the time-domain (TD) reflection and transmission coefficients are derived and successfully validated using an equivalent circuit representation. The cases of the constant-to-linearly increasing and harmonic temporal profiles are analyzed in detail. Illustrative numerical examples demonstrating the pulse shapes of the temporally modulated EM fields are presented.