IL

155 records found

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 ...
The transient electromagnetic (EM) excitation of a narrow slot in a perfectly electrically conducting (PEC) screen that separates two homogeneous dielectric halfspaces, a simplified model of a typical feeding structure of leaky lens antennas, is analyzed numerically in the time d ...
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 fosteri ...
A causality preserving interpretation of the electromagnetic (EM) leaky-wave (LW) propagation in space and time is proposed for the first time. The Cagniard-deHoop (CdH) joint transform technique is applied for elucidating the relation between time-domain (TD) head waves (HWs), b ...
A straightforward approach to achieve the prescribed shape of the far-field electromagnetic (EM) pulse radiated from a narrow slot antenna is introduced. It is demonstrated that the specified radiated pulse shape in a given direction can be approximately attained via a simple sig ...
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 ...
The critical relevance of ensuring the excitation's causality in electromagnetic (EM) simulations is exploited by the computation of strictly causal time domain interaction integrals as they occur in the partial element equivalent circuit (PEEC) method. Under the hypothesis of th ...
Time-domain (TD) methods for the solution of Maxwell's equations are particularly appealing for their ability to provide the overall characteristics of an electrical system in a single simulation run. In many situations, such TD methods require computing the system's impulse resp ...

Excitation in Time-Domain Analyses

A Pivotal Element for Accurate Simulations

A simple and efficacious modality of introducing causal excitations in CST Studio Suite® time-domain simulations is described. It makes use of (concatenations of) so-called discrete ports that are shown to accurately substitute Dirichlet boundary conditions and replicate dipole e ...
Thin-wire structures in the presence or absence of a ground plane are analyzed numerically in the time domain (TD) with the aid of the Cagniard-DeHoop method of moments (CdH-MoM). It is demonstrated that the TD solution of such problems can be cast into the form of discrete time- ...
The critical relevance of ensuring the excitation’s causality in electromagnetic (EM) simulations is validated via theoretical arguments and simulation results. Two families of model pulses with an implicitly causal behavior, namely the windowed-power (WP) and the power-exponenti ...
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 demons ...
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 ...
Pulsed electromagnetic (EM) scattering from a relatively narrow superconducting strip is analyzed with the aid of the EM reciprocity theorem and the Cagniard-DeHoop (CdH) technique. The analysis yields a stable convolution-type equation that is solved using the marching-on-in-tim ...
An improvement of the wide-angular scan-loss compensation (SLC) and sidelobe level (SLL) in a small linear array with 23 elements is discussed. The array integrates small subarrays with an optimized pattern for SLC, while the SLL suppression is obtained by using a combination of ...
Closed-form time-domain (TD) analytical expressions describing the electromagnetic (EM) signal transfer between two vertical dipoles through a thin, highly contrasting layer with combined magneto-dielectric properties are derived via the Cagniard–DeHoop (CdH) technique with the T ...

Pulsed EM field transfer between a horizontal electric dipole and a transmission line

A closed-form model based on the Cagniard-DeHoop technique

The pulsed electromagnetic (EM) field transfer between a horizontal electric dipole (HED) and a transmission line is described analytically with the aid of the time-domain (TD) reciprocity theorem and the Cagniard-de Hoop technique. A suitably chosen wave-slowness representation ...
An advanced design, adding a significant first sidelobes level (FSLL) improvement to a previously introduced wide-angular-scanning, linear array prototype with demonstrated scan-loss compensation (SLC) and sidelobes suppression features is discussed. The linear array makes use of ...

Electromagnetism in the Electrical Engineering Classroom

Dominant trends in teaching classical electromagnetic field theory and innovation vectors

This article explores some dominant trends in teaching classical electromagnetic (EM) field theory in electrical engineering (EE) undergraduate curricula. The acronym EM will be used interchangeably to designate either electromagnetic or electromagnetism. The intended significanc ...
A novel pulsed photoconductive THz source is presented that is able to radiate mW-level average powers, over a large bandwidth by exploiting both the optical and electrical properties of photoconductive sources and the ultrawideband properties of connected antenna arrays. An opti ...