XFdtd's system sensor collates discrete frequency data, and is generated by XF without the need for a specific sensor. The following results are calculated when there is a single active port in the simulation space.

When S-parameters are requested while creating a simulation, each active port has both a corresponding run and associated output. The tabular results available for the system sensor are consistent with a single active component. In some cases, the results are equivalent to those computed for a circuit component.

Net available power, $P_{av}$, is equivalent to the power available from either the active circuit component or waveguide.

$$P_{av} = P_{av\text{,active source}}$$

Net input power, $P_{in}$, is equivalent to the input power from either the active circuit component or waveguide.

$$P_{in} = P_{in\text{,active source}}$$