Boundary Type

E-Field Behavior

Used to model...

Default Boundary Conditions (Natural and Neumann)

Field behaves as follows:

• Natural boundaries — The normal component of D changes by the amount of surface charge density. No special conditions are imposed.
• Neumann boundaries — E is tangential to the boundary. Flux cannot cross a Neumann boundary.

Ordinary E-field behavior on boundaries. Object interfaces are initially set to natural boundaries; outer boundaries are initially set to Neumann boundaries.

Insulating

Same as Neumann, except that current cannot cross the boundary. An insulating boundary is only available for electrostatic solutions that include a DC conduction analysis.

Thin, perfectly insulating sheets between touching conductors.

Symmetry

Field behaves as follows:

• Even Symmetry (Flux Tangential) — E is tangential to the boundary; its normal components are zero.
• Odd Symmetry (Flux Normal) — E is normal to the boundary; its tangential components are zero.

Planes of geometric and electrical symmetry.

Matching
(Independent and Dependent)

The E-field on the dependent boundary is forced to match the magnitude and direction (or the negative of the direction) of the E-field on the independent boundary.

Planes of symmetry in periodic structures where E is oblique to the boundary.

Thin Layer

When two parts of the domain are separated by a thin volume, it can be modeled by a Thin Layer. This boundary creates a field discontinuity (voltage drop) between the two sides of the selected surface based on the material bulk properties and thickness.

Thin conducting domains