Transmission Line
Selecting Insert - Add Modeled Element from the main menu of the project editor tab opens the Edit Element dialog box. If you select "Transmission Line" from the Element drop list, the dialog box is updated to add an ideal transmission line.
Three text entry boxes appear for Port 1, Port 2 and Ref of the transmission line. Enter the desired node number in each text entry box. You may connect the transmission lines between three nodes of the network or between two nodes and ground (GND).
There are three element parameters available in the Element Parameters section of the dialog box.
Impedance: The impedance of the transmission line.
Electrical Length: The electrical length of the transmission line.
Frequency: The frequency where the electrical length of the transmission line specified above is evaluated.
The units are those set on the Units page of the Circuit Settings dialog box.If you wish to use a variable for an Element Parameter, click on the 
in the drop list and select an existing variable. If you wish to create a new variable, select <Add Variable> from the drop list. The Add/Edit Variable dialog box is opened which allows you to create a new variable.
When the ideal transmission line is added to your network, its entry is listed as "TLIN."
