Default Boundary Conditions (Natural and Neumann)

Field behaves as follows:

• Natural boundaries — Tangential H and normal B are continuous across surfaces without current density distribution; tangential H has a jump if the surface has current density distribution.
• Neumann boundaries — Magnetic Field is tangential to the boundary and flux cannot cross it.

Initially, object interfaces are natural boundaries; outer boundaries and excluded objects are Neumann boundaries.

Vector Potential

Sets the magnetic vector potential A_z(t), or rA_f(t), on the boundary. The behavior of H depends on whether A_z(t) or rA_f(t) is constant or functional.

Magnetically isolated structures.

Impedance

Includes the effect of induced currents beyond the boundary surface based on tangent component of H along the impedance boundary.

Conductors with very small skin depths.

Symmetry

Field behaves as follows:

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

Planes of geometric and magnetic symmetry.

Balloon

Models the case where the structure is “infinitely” far away from other magnetic fields or current sources.

Magnetically isolated structures.

Matching

(Independent and Dependent)

The Magnetic Field on the dependent boundary is forced to match the magnitude and direction of the Magnetic Field on the independent boundary. If a plus sign is used, the fields oscillate in phase, if a minus sign is used the fields will oscillate 180 degrees out of phase.

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