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The simplest RF circuit analysis type in [[RF.Spice]] is the "AC Frequency Sweep" Test. As mentioned earlier, this is identical to the AC frequency sweep test of [[B2.Spice A/D]]. The only difference here is that the frequency-domain models of [[Multiport Networks|multiport networks]] and transmission line segments or components are added to the analog or mixed-mode simulation of your circuit. Just as in [[B2.Spice A/D]], the AC Test is run from the Test Panel of the Toolbox.

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RF circuits are typically characterized as [[Multiport Networks|multiport networks]] (usually one-port or two-port). In many practical cases, rather than computing the input or output voltages or currents, you might be more interested in the port characteristics of your RF circuit. For one-port circuits, you would designate an input port (Port 1) and would like to calculate its return loss or input impedance. For two-port circuits, you would specify an input port (Port 1) and an output port (Port 2) and would be interested in finding its insertion loss or gain. The most commonly used set of [[parameters]] for RF circuit characterization are the scattering (S) [[parameters]]. The "Network Analysis Test" is one of the AC-type [[tests]] of [[B2.Spice A/D]], which is of particular importance to [[RF.Spice]]. Network analysis computes four sets of [[parameters]]: S, Z, Y and H. Of these, S-[[parameters]] and the "Smith Chart" are of primary interest, although Z-[[parameters]] are also frequently sought.