XF displays discrete frequency results for a circuit component in a table containing all of the available results for the selected port. The columns report results for each steady-state frequency that was specified when creating the simulation.

There are two types of circuit components in XF, each with a different impact on results. Lumped component results are computed based on the single cell edge where the excitation is placed, and distributed component results are determined based on the area associated with the excitation.

## Single Active Component

An active component has a feed circuit component definition and excites the simulation space. When S-parameters are requested, there is only one active component at a time and all other feeds are treated as passive components. The active circuit component's results are defined as follows.

Characteristic impedance, $Z_c$, is the impedance of the circuit component. It is determined based on the circuit component definition rather than by running a simulation. For example, a voltage source with a resistance of 50 ohm has a characteristic impedance of 50 ohm regardless the impedance of the structure it is exciting.