</table>
==Defining the Gap Source and & Project Observables ==
A dipole antenna can be excited using a gap source, which is the simplest source type in [[EM.Libera]]. A gap source can be placed on a line object (line gap), or on a rectangle strip object (strip gap). The line gap is intended for Wire MoM simulation, while the strip gap is intended for Surface MoM simulation. A line gap source creates an infinitesimal gap on the line and connects a voltage source across the gap. To define a gap source, right-click on the <b>Gap Sources</b> item in the âSourcesâ section of the navigation tree, and select <b>Insert New Line Gap Sourceâ¦</b> The Line Gap Source Dialog opens up.