Changes

As an example, consider the simple RLC circuit of Tutorial Lesson 2, which is shown here in the opposite figure. First, we treat this circuit as a one-port network, with its port established at the voltage source. The characteristic or reference impedance Z0 is set to its default value of 50 Ohms. The frequency sweep is set from 1MHz to 1GHz on a decade scale with 50 points per interval. The figures below show the Z/Y/S parameters of this one-port network plotted on both Cartesian graphs and Smith chart.

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[[File:RFAC3.png|thumb|left|640px| An RF circuit consisting of a two-port network and connecting transmission line segments.]]

As an example, consider the RF circuit shown in the opposite figure, which was earlier examined in the discussion of AC frequency sweep test. This circuit can be treated as a one-port network with its input port defined between nodes 2 and 0, i.e. between the source's internal resistor and the input T-line segment. As a one-port, the circuit has a single s11 and a single z11 parameter. The first figure below shows the Smith chart for the return loss (s11) over the frequency range 1-10 GHz at larger steps of 100MHz. The second figure below shows Cartesian plots of the real and imaginary parts of z11 over the same frequency range both with finer steps of 10MHz.