Project 2 Input impedance of TL (Due Oct 6 in class)

By Dr. Fei Wang

Objective:

The objective of this project is to understand the input impedance of a transmission line with open or short load.  You should design an ADS project to plot input impedance of transmission line as a function of frequency. A sample design could look like the following.

You should adjust the load to open or short circuits and simulate them separately. Find a way to plot Zin as a function of frequency. A sample result is given below. Your report should include your design schematic, results for open load and short load (for each scenario, plot magnitude and phase in separate plot), as well as your method to calculate Zin using ADS program.

Questions:

1. How did you calculate Zin using ADS program?

2. What is the difference between open load and short load results?

3. Mathematically derive Zin expression (refer to lecture notes and book).

The following question in regarding part 3 in project 1. In project 1, you practice to analyze the transient response of a TL. Answer the following question using your results. HINT: refer to chapter 2-11, equation 2.126 and 2.128)

4. Compute Gamma 1 from the component values on the schematic (reflection coefficient at 1st reflection, at interface between source and transmission line)

5. Compute Gamma 1 using simulation results. Does it agree with question 1?

6. Compute Gamma 2 from the component values on the schematic (reflection coefficient at the reflection at far end of line, at the load)

7. Compute Gamma 2 using simulation results. Does it agree with question 3?

8. Compute Gamma 3 from the component values on the schematic (reflection coefficient at input, after "round-trip" return)

9. Compute Gamma 3 using simulation results. Does it agree with question 5?