EM Modeling Software Acronyms and Definitions
 ABC  Absorbing Boundary Condition
 An mathematical technique for truncating computational regions that attempts to emulate an
open boundary by absorbing all the incident electromagnetic energy.
EM modeling techniques based on the solution of the differential form of Maxwell's equations
require an absorbing boundary to model open radiation problems.
 ACES  Applied Computational Electromagnetics Society
 ACES is a professional society
that provides a forum for issues relevant to numerical modeling in applied electromagnetics
including computational techniques, electromagnetic modeling software, and applications.
 AF  Antenna Factor
 The ratio of the received field strength to the voltage appearing at the terminals of
a receiving antenna OR the ratio of the transmitted field strength at a specified distance
to the voltage applied to the terminals of a transmitting antenna.
Antenna factors are functions of position and frequency.
 BEM  Boundary Element Method
 A popular electromagnetic modeling technique that employs the method of moments to solve
electric or magnetic field integral equations. 3D BEM codes utilize mesh elements that
are usually lines,
rectangles or triangles covering the surfaces at the interfaces between two
different materials.
 BIE  Boundary Integral Equation
 Another name for the Boundary Element Method (see above).
 BIRME  Boundary Integral  Resonant Mode Expansion
 A method for the fast calculation of the modes of arbitrarily shaped
hollowconducting waveguides or cavities.
 BOR  Body Of Revolution
 An object that can be generated by rotating a generating arc about the axis of symmetry
(i.e. in cylindrical coordinates can be oriented with its axis in the z direction and all
surfaces will be described by functions that are independent of phi.)
 CEFC  Conference on Electromagnetic Field Computation
 A biennial conference sponsored by the IEEE Magnetics Society.
 CFIE  Combined Field Integral Equation
 A weighted combination of 2 integral equations: one relating electric currents and/or
magnetic currents to electric field strength at a distance (EFIE); the other relating electric
currents and/or magnetic currents to magnetic field strength at a distance (MFIE).
Integration is over a surface for 3D problem geometries or over a line for 2D geometries.
Boundary Element Methods (BEM) generally employ a moment method to solve an EFIE,
MFIE or CFIE.
 CGM  Conjugate Gradient Method
 An iterative method for solving large systems of linear equations.
 EFIE  Electric Field Integral Equation
 An integral equation relating electric currents and/or magnetic currents to electric
field strength at a distance. Integration is over a surface for 3D problem geometries or
over a line for 2D geometries. Boundary Element Methods (BEM) generally employ a moment
method to solve an EFIE, MFIE or CFIE.
 EMAP  Electromagnetic Analysis Program
 An EM modeling program based on a hybrid FEM/MOM technique distributed and
supported by Clemson University.
 EMC  Electromagnetic Compatibility
 The ability of an electronic device or system to function without error in its
intended electromagnetic environment.
 EMLIB  (presumably ElectroMagnetic LIBrary)
 EMLIB is a web site
devoted to the free distribution of electromagnetic modeling software and related information.
 ERP  Effective Radiated Power
 The product of a transmitter power output and the antenna gain, taking into consideration
any losses from the transmission line, connectors, couplers, etc.
 ESA  Electrostatics Society of America
 The ESA is a
nonprofit professional
society that is devoted to the advancement and improved understanding of electrostatics.
 FDTD  Finite Difference Time Domain
 A very popular numerical EM modeling technique that applies a finite differencing scheme
to approximate the differential form of Maxwell's equations in the time domain.
The technique typically used cubical mesh elements with an offset between Efield mesh
nodes and Hfield mesh nodes.
 FEM  Finite Element Method
 A popular numerical EM modeling technique that solves a differential form of Maxwell's
equations, usually in the frequency domain. 3D FEM techniques typically employ tetrahedral
or brickshaped elements.
 FEMTD  Finite Element Method Time Domain (also FETD)
 A numerical EM modeling technique that solves a differential form of
Maxwell's equations in the time domain.
 FIT  Finite Integration Technique
 A numerical EM modeling technique that solves a differential form of Maxwell's
equations in the time domain.
It is similar in many respects to an FDTD technique, but it allows the mesh elements to
have a noncubical shape.
 FSS  Frequency Selective Surface
 A material surface that exhibits electromagnetic reflection or absorption properties
that differ sharply at frequencies within a certain band.
 FSV  Feature Selective Validation
 A method for comparing two sets of data (for example, to quantify the agreement
between measured and modeled results).
 FVTD  Finite Volume Time Domain
 A numerical EM modeling technique that solves a differential form of Maxwell's
equations in the time domain. This technique is also similar to an FDTD technique,
but it allows the mesh elements to have a noncubical shape.
 GEMACS  General Electromagnetic Model for the Analysis of Complex Systems
 A commercial EM modeling code employing a 3D hybrid MOM/UTD/FDFD technique.
 HFSS  High Frequency Structure Simulator
 A popular numerical EM modeling code marketed by ANSYS based on a
finite element modeling technique. Originally, this software was called the "High Frequency Structure Simulator" and was developed by AnSoft.
 IEEE  Institute of Electrical and Electronics Engineers
 IEEE is the world's leading
professional association for the advancement of technology. The IEEE name was originally
an acronym for the Institute of Electrical and Electronics Engineers, Inc.
Today, the organization's scope of interest has expanded into so many related fields,
that it is simply referred to by the letters IEEE (pronounced EyetripleE).
 MOMTD  Method of Moments Time Domain
 A relatively obscure electromagnetic modeling technique that employs a BEM/MOM solver,
but operates in the time domain.
 LU  Lower triangular / Upper triangular
 A representation of a matrix as the product of two alternate matrices;
one where all the elements in the upper right half of the matrix are zero,
and one where all the elements in the lower left half of the matrix are zero.
 MOL  Method of Lines
 A technique for solving partial differential equations (PDEs) typically using
finite difference relationships for the spatial derivatives and ordinary differential
equations for the time derivative.
 MOM  Method of Moments
 A numerical method for solving integrodifferential equations that expands the unknown
quantity into a sum of simple "basis" or "expansion" functions,
then weights the resulting
set of equations using an equal number of "test" or "weighting"
functions resulting in a
set of N equations in N unknowns. [Note: Electromagnetic modeling codes employing the
boundary element method (see BEM) are often referred to as moment method codes,
because they generally employ a moment method technique.]
 MOMTD  Method of Moments Time Domain
 A relatively obscure electromagnetic modeling technique that employs a BEM/MOM solver,
but operates in the time domain.
 MTL  Multiconductor Transmission Line
 A cable or wiring harness with more than two wires usually carrying more than one signal.
 NEC  Numerical Electromagnetics Code
 A popular electromagnetic modeling code that is distributed freely.
It applies a moment method to solve an electric field integral equation on wires and/or a
magnetic field integral equation on surface patches. It is one of the most accurate and
efficient thin wire modeling codes available. NEC2 is available as source code
and uses a textbased interface.
There are several commercial codes available that use the same basic technique,
but add graphical interfaces and other features.
 PDE  Partial Differential Equation
 Describes any partial differential equation, but is often used in EM modeling to refer
to the differential form of Maxwell's equations or modeling techniques that
solve Maxwell's equations in this form.
 PEC  Perfectly Electrically Conducting
 Describes a material with infinite conductivity (i.e. will not support an electric field).
 PEEC  Partial Element Equivalent Circuit
 An electromagnetic modeling technique that breaks a problem geometry into small pieces
and models all electromagnetic interactions between the pieces as circuit elements.
 PMC  Perfectly Magnetically Conducting
 Describes a material with infinite permeability (i.e. will not support a magnetic field).
 PML  Perfectly Matched Layer
 A particular type of absorbing boundary condition originally formulated by
Berenger in 1994.
 RF  Radio Frequency
 A frequency at which electromagnetic radiation of energy is useful for communications.
Radio frequencies are designated as very low: 3 kHz to 30 kHz, low: 30 to 300 kHz,
medium: 300 to 3,000 kHz, high: 3 to 30 MHz, very high: 30 to 300 MHz,
ultrahigh: 300 to 3,000 MHz, super high: 3 to 30 GHz, and extremely high: 30 to 300 GHz.
 RWG  RaoWiltonGlisson
 Triangular basis functions used by many EM modeling codes employing
moment method solution techniques.
The functions are named after the three researchers who developed them:
Sadisiva M. Rao, Donald R. Wilton and Allen W. Glisson.
 SPICE  Simulation Program with Integrated Circuit Emphasis
 Very popular circuit simulation software originally developed at the University of California,
Berkeley and now distributed in many forms as implemented by a variety of commercial and
noncommercial organizations.
 TDAIM  Time Domain Adaptive Integral Method
 A numerical method for efficiently solving hybrid volumesurface integral equations.
 TDIE  Time Domain Integral Equation
 A unique EM modeling technique that solves the integral form of Maxwell's equations
in the time domain.
 TEM  Transverse ElectroMagnetic
 An electromagnetic plane wave where the electric and magnetic fields are perpendicular to each
other everywhere and both fields are perpendicular to the direction of propagation.
TEM cells are often used to generate TEM waves for radiated immunity (RI) testing.
 TLM  Transmission Line Matrix
 An electromagnetic modeling technique that emulates electric and magnetic field
interactions using circuit elements connected by a grid of transmission lines.
 UTD  Uniform Theory of Diffraction
 An electromagnetic modeling technique for modeling electrically large objects.
The uniform theory of diffraction employs quasioptical techniques and uses ray diffraction
to determine diffraction coefficients for each diffracting objectsource combination.
 WPBC  Waveguide Port Boundary Condition
 A boundary condition used in EM modeling to simulate the junction occurring at a
waveguide or coaxial cable feed without having to model the interior of the waveguide or cable.
