It´s About Time

In the past years, time-domain methods have reached a level of maturity that makes them most suitable for the simulation of a variety of EM devices. They have a number of advantages: capability of simulating truly gigantic structures, due to their high simulation speed and low memory consumption; ability to furnish broadband results in a single simulation run; and, more recently, they offer good accuracy in the approximation of problem geometry through improved meshing techniques adapted to arbitrary surfaces. In the time domain, EM simulations can most naturally be coupled to simulations in other domains of physics. This broadens their domain of applicability to entire technical systems and allows a variety of physical effects to be taken into account in the design stage. This article on time-domain methods should not let the reader forget that frequency-domain methods also have great advantages and that, for specific devices or simulation types, a frequency-domain method might be the best or the only one applicable. However, we do live in a time-domain world. To quote E. Bogatin [23]: "The most important quality of the frequency domain is that it is not real. It is a mathematical construct. The only reality is the time domain."