RS:

abbreviation for "Rotational Symmetry" or "Rotationally Symmetric" AKA "Axisymmetric" or "Azimuthal Symmetry"

This refers to a physical geometry which could be generated by the sweep of a planar cross-section around a central axis. This can enable simulations which use the 2D cross-section of the geometry rather than a full 3D drawing and solution. So long as the physical problem is truly RS, the solution obtained is the correct solution to the full 3D problem.

2D:

abbreviation for "Two Dimensional"

Although all real problems involve three dimensional geometry, there are many cases where a 2D analysis provides a sufficient answer. In those cases, since it is faster and easier to draw, it is a more practical approach to simulation.

Appropriate Cases: 2D is appropriate for geometry that can be represented by a planar cross-section which could be swept in the normal direction by some length in order to obtain the full geometry. The 2D analysis will solve as if the geometry is infinitely long, then scale any length-dependent numbers (energy, force, torque, etc.). Therefore, it is important that any effects (such as fringing of the fields) due to the real ends of goemetry do not introduce significant error.

BEM:

abbreviation for "Boundary Element Method"

The Boundary Element Method simulates space domain problems by using a discretization of the physical surfaces to solve for appropriate sources. For example, in an electric problem the solution is a distribution of "free" charges on conductors and "bound" charges on dielectrics. Once the source distribution is obtained, results such as field values, torque, energy etc. are obtained by appropriate integrations from the distribtution. For example, integrate q/r² to a point to obtain electric field values there.

MoM:

abbreviation for "Method of Moments"

This refers to the same method as BEM. It is commonly known as MoM in high frequency electromagnetic simulation and as BEM elsewhere.

FEM:

abbreviation for "Finite Element Method"

The Finite Element Method simulates space domain problems by solving a potential function over some region of space with defined boundaries. This requires a discretization of that region with elements. Appropriate numeric differentiation of the potential produces physical results. For example, the electric field at a spot is obtained from E = grad(V).

Direct BE:

"Direct Boundary Element Method"

This is a variant on BEM in which the fields are computed at the boundaries rather than equivalent sources. It requires more unknowns than standard BEM, hence takes longer to solve with a given set of elements. However, it provides superior results for some cases - notably when there are many order of magnitude change in a physical property across an interface (permeability, permittivity).

(Direct BE is available as an advanced solver setting in AMPERES and FARADAY.)

CAD:

abbreviation for "Computer Aided Design"

CAE:

abbreviation for "Computer Aided Engineering"

CAM:

abbreviation for "Computer Aided Manufacturing"

High Frequency:

also called "Full Wave"

In analysis this does not refer to specific frequencies, but to the physical considerations which need to be included for a given geometry size. Any of the following indicate that the model is "high frequency":

• If the mathematics of the Electric and Magnetic fields are "tight coupled".
• If the propagation time (distance divided by speed of light) between parts of the model is comparable to, or smaller than the period (inverse of the frequency).
• If you are looking for effects related to wavelength or propagation time of signals.
• For "low frequency" the wavelength is far larger than the geometry. Otherwise, the problem is "high frequency".