Where To Find This Example
Sweeping the Impedance of a PORT
MWOffice and Analog Office do not allow the impedance of a PORT element to be swept using the SWPVAR block. This example shows alternatives for getting the measurements you need.
If the PORT is only being used for termination, not for measurements that require a port, then the simplest solution is to replace it with a LOAD element. Otherwise, use an LTUNER or similar element from Circuit Elements > General > Passive > Other in the Element browser.
"Using_LOAD" schematic shows a setup for sweeping the complex impedance of a LOAD element. "Using_LTUNER" shows how to use an LTUNER instead, so that port 2 can still be used for measurements. The tuner elements allow you to set the gamma, but restrict the magnitude of gamma to less than 1. So, negative real values for Z that result in |gamma| > 1 will not work.
"S11" shows s11 for both schematics.
"Polar Plot of Complex Z" shows the complex input impedance in both schematics, looking from port 1.
You can use the tuner to vary EL of the transmission line and see its effect on the swept Z in the graphs. To use the tuner to vary Z, disable the SWPVAR blocks, and the Zr and Zi equations. The tunable Zr and Zi are defined in the Global Definitions window.