University of Cincinnati
ECE&CS Department
EE-611
Microwave Communication

Prepared by: Prof.Altan M. Ferendeci

Hewlett-Packard Libra Microwave Circuit Simulation Software

• Log into the computers in either on the 8'th or 5'th floors (Unix Machines)
• Enter Libra
• Wait until the following Libra 6.1/Main appears as shown in Figure below.
• Click on OK
• Pull down the Project Menu
• Enter a new Project File name: maybe Work or if you have already created a Work file open that file.
• Next Click on schem Ikon
• Continue below the first figure

• The following Schematic window appears
• At present we will use the LineCalc only
• Pull down the Tools Menu
• Goto LineCalc and click on Start
• Continue below the second figure

• The following LineCalc window appears.
• You can chose any type of transmission line by clicking on Select
• For this demo, chose MLIN (Micro Strip Line)
• Click on Apply and then click OK
• You can change Frequency by pulling down the corresponding menu and entering your frequency in GHz
• You can change your length unit by pulling down on Length menu and clicking on the unit you want, i.e., mils, mm, etc.

• You can also modify parameters such as Substrate, Tand etc., by clicking on them and making the changes.
• Note everytime you make a change first click Apply and then OK.
• The LineCalc window displays various parameters associated with the transmisson line. In the upper center
  • Substrate parameters such as
    • Dielectric constant, ER
    • Sunbstrate height, H
    • Metal thickness, T
    • Resistivity relative to Gold, RHO
    • Tand, TAND
    are displayed
  • In the lower center, the calculated results
    • Effective Dielectric Constant, K_EFF
    • Loss per length L
    • Skin depth
    are displayed

• On the right hand side, parameters are entered. Either
  • various physical widths and lengths, W and L are entered.
  and by clicking the down arrow,
  • Characteristic Impedance, Z0
  • Effective length in terms of wavelength E_EFF
  are calculated.

• Otherwise, ZO and E_EFF can be entered and by clicking the up arrow, corresponding W and L are calculated

Try various combinations and familirize yourself with the LineCalc.