Figure 12 uses the Plasmonic Wire Grating application from the Wave Optics Module application library to show the Model Builder window and the Settings window for the selected Wave Equation, Electric 1 feature node. The Wave Equation, Electric 1 node adds terms representing the Helmholtz wave equation to the model equations for, in this case, all domains in the model. As this is an example of a periodic problem, the Wave Equation, Electric 1 node is a subnode to the Periodic Structure 1 node.
The simulation domain is delimited by boundary condition feature nodes. The default boundary condition feature for the physics interfaces in the Wave Optics Module is the Perfect Electric Conductor feature. For the example in Figure 12 the top Perfect Electric Conductor 1 feature node is overridden by the Periodic Structure 1 node. However, the Perfect Electric Conductor 1 subnode to the Periodic Structure 1 feature node is overridden by two Periodic Port feature nodes and a Floquet Periodic Condition feature node. The Periodic Port features are used for exciting and absorbing waves and the Floquet Periodic Condition relates fields on parallel opposing boundaries with Floquet periodicity conditions.

Figure 13 shows the Wave Optics interfaces, as displayed in the Model Wizard for this module.