ECE320H1F: Fields and Waves
Laboratory 3: Design of a Double Stub Matching Network
Marking Scheme
Show your calculations for all work, including theoretical diagrams and plots. Measurement graphs
refer to intrumentation screen captures obtained in the laboratory. Include the full name, student
number and PRA session for all group members on the laboratory report.
4.2 [ 1 ] Measurement Smith chart plot of load impedance versus frequency.
[ 1 ] Measurement Smith chart plot of load impedance versus frequency, de-embedded by
0.2 ns.
[ 3 ] Equivalent electrical distance (in wavelengths) at 800 MHz associated with the 0.2 ns port
extension. Demonstrate that this additional distance corresponds to the Smith chart
transformation seen in the measurement.
4.3 [ 5 ] Determination of 𝑧A by rotating 𝑧L by 𝑑0 = 3.4 cm on the Smith chart, and transformation
of 𝑧A to 𝑦A on the Smith chart.
4.4 [ 20 ] Design of the double stub matching network for the load provided using a Smith chart.
Show the calculated stub lengths ˆ𝑙1 and ˆ𝑙2 in terms of wavelengths, and 𝑙1 and 𝑙2 in terms
of cm. Determine all lengths for both fundamental solutions.
4.5 [ 3 ] Experimental determination of the final stub lengths for both fundamental solutions to
achieve a match between the load and the line.
[ 2 ] Measurement Smith chart plots of the matched load for both fundamental solutions.
4.6 [ 5 ] Measurement plot of the final VSWR and measurement of bandwidth for both fundamental solutions. Relate the VSWR bandwidth criteria to the reflection coefficient and
its value in decibels (20 log|Γ|). Give some reason for the bandwidth limitation.
[ 5 ] Discussion of how the measured results compare to the theoretically calculated ones;
outline any potential sources of errors.
[ 5 ] Presentation and neatness.
[ ] Indicates the number of marks out of 50 total marks
