Transition Boundary Condition
The Transition Boundary Condition is used on interior boundaries to model a sheet of a medium that should be geometrically thin but does not have to be electrically thin. It represents a discontinuity in the tangential electric field. Mathematically it is described by a relation between the electric field discontinuity and the induced surface current density:
where indices 1 and 2 refer to the different sides of the layer. This feature is not available with the Electromagnetic Waves, Transient interface.
The Transition Boundary Condition is based on the assumption that the wave propagates in the normal direction in the thin layer. Thus, the wave could be incident in the normal direction or the wave could be refracted to propagate in a direction close to the normal direction. The latter condition is fulfilled for a good conductor.
The thickness of the layer should also be less than the radius of curvature for the boundary.
A consequence of the normal direction propagation assumption is that the Transition Boundary Condition is not compatible with mode analysis, as for mode analysis it is assumed that the wave predominantly propagates in the out-of-plane direction whereas the normal to the boundary is in an in-plane direction.
The Surface Roughness subnode is available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu.
Transition Boundary Condition
Select an Electric displacement field model — Relative permittivity (the default), Refractive index, Loss tangent, loss angle, Loss tangent, dissipation factor, Dielectric loss, Drude-Lorentz dispersion model, or Debye dispersion model. See the Wave Equation, Electric node, Electric Displacement Field section, for all settings.
Select the Electrically thick layer check box (unselected by default) to make the two domains adjacent to the boundary uncoupled. When the Electrically thick layer check box is unselected, enter a Thickness d (SI unit: m). The default is 0.01 m.