== Excitation Sources ==
Your planar structure must be excited by some sort of signal source that induces electric surface currents on metal parts and , magnetic surface currents on slot traces, and conduction or polarization volume currents on vertical vias and embedded objects. The excitation source you choose depends on the observables you seek in your project. EM.Picasso provides the following source types for exciting planar structures:
* '''[[Common_Excitation_Source_Types_in_EM.Cube#Lumped_.26_Gap_Sources | Gap Sources]]'''