The representation of electromagnetic
structures by lumped element circuits is revisited. Net-
work models can be established by a subsequent ap-
plication of system identification and circuit synthesis
methods to data obtained by numerical simulation or
from measurement. Network models provide a com-
pact description of electromagnetic structures and can
contribute significantly to the formulation of electro-
magnetic field problems and their efficient solution. On
the field level network methods are introduced by seg-
mentation of the electromagnetic structures and appli-
cation of the field form of Tellegen’s theorem. Methods
for synthesis of lumped element models for lossless as
well as lossy linear reciprocal multiports and for ra-
diating structures are discussed. The state equation
method as a general framework for lumped element
network description is presented. Discrete time repre-
sentations on the basis of Richards transformation and
wave digital filter formulation are introduced.
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