Introduction to Radio Frequency
RF Network Final Report
By Victor Aguilar and Hamza Ghosheh
Introduction
This report provides a detailed analysis of two critical experiments conducted using RF
calibration and network boards. The first section evaluates the performance of a
calibration board, focusing on the open, short, and load characteristics. The second
section compares the theoretical versus measured performance of Pi and T networks
with an additional analysis of a Thru line. These evaluations are crucial for
understanding the effectiveness and accuracy of RF measurement setups in practical
scenarios.
Calibration Board Performance Evaluation
Methodology
Measurements were conducted using a network analyzer, calibrated for accurate
readings. The board was tested under three conditions: open, short, and load.
Reflection coefficients (S11) were recorded across a specific frequency range to assess
performance.
Results and Discussion
Open Circuit Analysis
● Expected Results: High reflection due to infinite impedance.
● Measured Results: Magnitude close to 1, phase showed significant variation,
confirming the expected capacitive nature.
Short Circuit Analysis
● Expected Results: High reflection due to zero impedance.
● Measured Results: Magnitude near 1, phase around -180 degrees, aligning well
with theoretical predictions.
Load Analysis
● Expected Results: Minimal reflection with matched load impedance (50 ohms).
● Measured Results: Low magnitude, phase near 0 degrees, indicating excellent
impedance matching.
Comparative Analysis
The calibration board showed accurate performance as predicted theoretically,
confirming its reliability for precise RF measurements.
Magnitude Plots (Left Column): These plots show the absolute values of each
S-parameter across the frequency range. You can observe how the magnitude of each
parameter varies, which can indicate how much signal is reflected or transmitted at
different frequencies.
Phase Plots (Right Column): These plots display the phase angle (in degrees) of each
S-parameter across the frequency range. The phase information is crucial for
understanding the behavior of the network in terms of signal delay and reflection
properties.
Performance Comparison of Pi, T, and Thru Networks
Methodology
The Pi, T, and Thru networks were analyzed using the same network analyzer,
measuring S-parameters like S11 and S21 to gauge each network's behavior across the
frequency spectrum.
Results and Discussion
Pi Network Analysis
● Theoretical Expectations: Expected to show specific filtering and impedance
transformation characteristics.
● Measured Results: Varied S11 and S21 magnitudes and phases indicate
complex impedance interactions, generally in line with theoretical designs meant
to manipulate signal paths.
T Network Analysis
● Theoretical Expectations: Similar to Pi but with potential differences in
impedance matching and signal attenuation.
● Measured Results: The measurements displayed differing reflection and
transmission characteristics compared to the Pi network, suggesting variations in
design efficacy.
Thru Line Analysis (Bonus)
● Theoretical Expectations: Near-perfect transmission with minimal reflection.
● Measured Results: Very high S21 magnitude close to 1 and very low S11
magnitude, confirming excellent performance as an ideal transmission medium.
Comparative Analysis
The Thru line exhibited optimal performance, serving as a benchmark for minimal signal
loss and reflection. Both Pi and T networks demonstrated their characteristic effects on
signal behavior, aligning closely with theoretical predictions, though with measurable
deviations that could be explored further.
S11 Magnitude Comparison: This plot shows the reflection coefficient magnitude for
each network, providing insights into how much of the signal is reflected by each
network type.
S21 Magnitude Comparison: This plot compares the transmission coefficient
magnitude, illustrating how efficiently each network type passes signals.
S11 Phase Comparison: This plot compares the phase of the reflection coefficient,
which helps in understanding the impedance characteristics and reflections at different
frequencies.
S21 Phase Comparison: This plot shows the phase of the transmission coefficient,
indicating phase shifts introduced by each network during transmission.
Conclusion
The calibration board and the network components (Pi, T, and Thru) have been
thoroughly analyzed, with results largely corroborating theoretical expectations. These
findings underscore the effectiveness of the boards for educational and practical
applications in RF engineering. Future work may involve a broader frequency range and
additional network types to further validate and refine RF measurement techniques and
tools.