# FDTD Glossary

A Glossary of FDTD and electromagnetic terms.

## Glossary

Name Definition Notes
ABC absorbing boundary conditions Taflove p.?
angular Frequency
Eisberg page129; GriffithsED page 368
complex division x = a + ib, y = c + id
x / y = ((ac + bd) + i(bc – ad)) / (c2 + d2)

complex multiplication x = a + ib, y = c + id
x * y = (ac – bd) + i(ad + bc)

evanescent waves decaying waves Balanis page 415
exp(x) lim (1 + x / alpha)alpha, as alpha => infinity
Far Field Distance from Source to Target >> wavelength Taflove p.477 (near to far field, Taflove pp. 478,203, ch8)
function, odd f(-x) = -f(x) Griffiths page104
function, even f(-x) = f(x) Griffiths page104
Hertz potentials polarization potentials Jackson page280
magnetic monopoles   Jackson pages273-275
Magnitude of A
|A|
|A| = sqrt(Ax2 + Ay2 + Az2) = sqrt(A · A) Feynman I-11-9; GriffithsED pp. 5,9; Edminister p.1 (absolute value) (also see absolute square)
material, anisotropic, non-isotropic constitutive parameters are function of direction otherwise isotropic Balanis page 71; Taflove p.52; Sadiku page 7
material, dispersive Constitutive parameters are a function of frequency of the applied field otherwise non-dispersive
(different frequencies travel at different speeds in the material)
Balanis page71; see section 4.3, Taflove p.52, (Taflove p.227: linear dispersion, non-linearity, non-linear dispersion, gain)
material, dissipative absorbs electromagnetic radiation, converts to thermal energy? Taflove p.52
material, homogeneous constitutive parameters are not a function of position within the material, otherwise non-homogeneous (inhomogeneous) Balanis page 71; Taflove p.52; Sadiku page7
material, linear constitutive parameters are independent of the applied field, otherwise non-linear Balanis page 71; Taflove p.52; Sadiku page7
MM Method of Moments Taflove p.2
Modes Field configurations which satisfy Maxwell’s equations and the boundary conditions are called modes (A mode is a particular field configuration)
common modes: TEM, TE, TM
Balanis pp. 129, 261
Near Field Taflove p.477 (near to far field, Taflove pp. 478,203, ch8)
orthogonal perpendicular (Euclidean geometry) GriffithsQM page27, GriffithsQM p.79
PEC perfect electric conductor Taflove p.?
PMC perfect magnetic conductor Taflove p.?
polar vectors   Jackson pages270-273
pseudo-vector (axial) Jackson pages270-273; GriffithsEM page204
quasi-static   Taflove1998 page627; Jackson page219; GriffithsED pp.308-309
RMS (root mean square)

For a plane Wave:

Where,

see Time average of <A>
SAR Specific Absorption Rate (watts/kg) Taflove page 530
spacetime, curved general theory of relativity (gravitation)
spacetime, flat special theory of relativity
Time average of A
<A>

To calculate

for a plane wave:

note:

therefore:

Feynman I-24-1,2; GriffithED page381
TE Transverse Electric Mode Taflove p.71
TEM Transverse Electromagnetic Mode, (E,H contained in a plane) Balanis pp.129-130; Modes defined: Balanis page 129
TM Transverse Magnetic Mode Taflove p.71
waveNumber
Eisberg page129
also called propagation vector (or wave vector), Bohm p.12; GriffithsED pp. 368,379