1. ELEC 401 MICROWAVE ELECTRONICS Lecture on Transient Analysis of TL
Instructor: M. İrşadi Aksun
Acknowledgements:
Art work on most of the illustrations, and most examples have been taken from the following book:
Elecrtromagnetics, by Branislav M. Notaros
Pearson Int. Ed., 2010

2. Outline
Chapter 1: Motivation & Introduction
Chapter 2: Review of EM Wave Theory
Chapter 3: Plane Electromagnetic Waves
Chapter 4: Transmission Lines (TL)
Chapter 5: Microwave Network Characterization
Chapter 6: Smith Chart & Impedance Matching
Chapter 7: Passive Microwave Components

3. Transmission Lines - Transient Analysis
Step response of a lossless TL with a purely resistive load
initial equivalent circuit as seen from the generator
steady-state equivalent circuit

4. Transmission Lines - Transient Analysis
Total voltage distribution, v(z, t), 0 ≤ z ≤ l, for RL, Rg > Z0

5. Transmission Lines - Transient Analysis
Voltage waveforms at the generator
Voltage waveforms at the load

6. Transmission Lines - Transient Analysis
matched generator (Rg = Z0) unmatched load
RL > Z0
RL < Z0

7. Transmission Lines - Transient Analysis
Example: A 30 cm long lossless 50W coaxial cable, filled with a homogenous material of e=2.25 and m=1, is fed by a voltage generator of 5V at t=0, with the internal resistance of 75W, and is terminated by RL=25W . Sketch the voltage waveforms at both ends of the line.
Voltage waveform at the generator
Voltage waveform at the load

8. Transmission Lines - Transient Analysis
Pulse Excitations

9. Transmission Lines - Transient Analysis
Example: A lossless 50-ohm TL (length=45cm and e=4) is terminated by an ideal voltage generator of rectangular pulse with magnitude of 10V and duration of 2ns. At the other end, the line is terminated in a purely resistive load of 200-ohm. Sketch the voltage waveform at the load.

10. Transmission Lines - Transient Analysis
Bounce Diagrams

11. Transmission Lines - Transient Analysis
Example: A 30 cm long lossless 50W coaxial cable, filled with a homogenous material of e=2.25 and m=1, is fed by a voltage generator of 5V at t=0, with the internal resistance of 75W, and is terminated by RL=25W . Construct voltage and current bounce diagrams, and obtain the total voltage and current waveforms at z=7.5cm.

12. Transmission Lines - Transient Analysis

13. Transmission Lines - Transient Analysis