ECE 5613 RF/Microwave Circuit Design Laboratory

Transmission Line Characterization Lab

A. Coaxial Lines

One-port Calibration: Perform a one-port calibration on the HP 8753 network analyzer. Perform all modeling in Agilent Advanced Design Systems and LineCalc.

  1. Evaluate 50 ohm and short terminations with and without calibration correction on a coaxial line. Print the [S] parameter response in dB magnitude and phase for all six cases. Also, in your notebook, sketch the terminations' impedances at 0.5, 1.0, and 2.0Ghz by observing the Smith Chart using the [MARKER] function. Is the response consistent with theory? If not, why?
  2. Hit [PRESET] to clear the calibration from memory.

Perform a 2-Port Calibration on the network analyzer. Perform all modeling in Agilent Advanced Design Systems and LineCalc.

  1. Measure the coaxial line as a two-port device.
  1. Calculate the total loss (1-|S11|2 -|S21|2) of the line and describe what physical parameters contribute to the loss.
  1. Determine the losses expected along the line (in dB/cm).
  1. Model the cable as an ideal 50 ohm transmission in ADS and compare simulation with experiment.

B. Transmission Lines

Use a 2-Port Calibration on the network analyzer. Perform all modeling in Agilent Advanced Design Systems and LineCalc.

  1. Measure the physical dimensions of the 50 ohm PC board and 50 ohm duroid transmission lines. Develop a CAD model of these lines and simulate the response from dc to 3GHz.
  2. Measure the response of the lines on the PC board (r = 4.78, h =62.5 mils) and duroid (r = 2.2, h = 62.5 mils) substrates.
  3. Plot the [S] parameters in dB of the two lines.
  4. Compare the measured and modeled return loss response. Describe any observable variations and explain why these exist.
  5. Compare the insertion loss of the two boards and determine the attenuation in dB/in and dB/g at 2 GHz.
  6. Estimate the length (in inches) of the transmission lines using the phase data. (Remember: = l)
  7. Measure the PC board Line A and Line B using the network analyzer.
  8. From the [S] parameter data, compute the characteristic impedance of the lines. Show your calculations.
  9. Measure the physical parameters (board thickness, line width, and line length) of Line A and Line B. Using ADS and LineCalc model Line A and Line B and indicate the theoretical value of ZO.
  10. Plot the simulated and measured line data. Compare and describe any differences that you may observe.

Jan03Drayton