# General Structure and Conventions

A SPICE circuit is described by a set of element lines that defines the circuit topology and element values, and a set of control lines that defines the model parameters and the run controls.
Note: The SPICE circuit in Feko describes the circuit only (subset of a standard SPICE circuit) therefore no run controls should be specified.

The first line in the input file must be the title and the last line must contain only the text, “.END”.

Each element in the circuit is specified by an element line that contains the element name, the circuit nodes to which the element is connected and the values of the parameters that determine the electrical characteristics of the element. An example SPICE .cir file is as follows:
Matching circuit
* Note that the subcircuit name should correspond to the name
* of the general network in CADFEKO (or in the *.pre file).
.SUBCKT MatchingNetwork n1 n2
* The next two lines describe a capacitor and an inductor
c1 n1 0 2.17pF
l1 n1 n2 42.29n
.ENDS MatchingNetwork
.END

The sections that follow contain extracts from the Berkeley SPICE manual regarding SPICE syntax. Only a small subsection of the commands is presented and the descriptions are incomplete. Please refer to the Berkeley SPICE manuals for a more detailed description of the required syntax.