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Updated: Jun 13, 2026
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Calibration of Vector Network Analyzer for Measurements in Radio Frequency Propagation Channels
Published on: June 2, 2020
VNA-Based Vector Reflection Coefficient Measurement Technique for Powered RF Signal Generators
Emre Cetin1, Aliye Kartal Doğan2, Anil Cetinkaya2,3
1Spark Measurement, 06530 Ankara, Türkiye.
Sensors (Basel, Switzerland)
|June 12, 2026
Summary
Measuring the reflection coefficient of an active RF signal generator is challenging due to interference. This study presents a novel method using a vector network analyzer (VNA) with frequency offset and narrow bandwidth for accurate measurements.
Area of Science:
- Electrical Engineering
- Radio Frequency (RF) Engineering
- Measurement Science
Background:
- Measuring the reflection coefficient of RF signal generators is complex when the output is active due to self-interference.
- Vector Network Analyzers (VNAs) are standard for reflection coefficient measurements but require signal isolation for active outputs.
- Existing methods struggle to accurately characterize RF signal generator performance under active output conditions.
Purpose of the Study:
- To propose and validate a unique method for measuring the output reflection coefficient of an RF signal generator while its output is active.
- To overcome the interference challenges posed by the generator's own output signal during measurement.
- To enable accurate characterization of RF signal generator performance across various operating power levels.
Main Methods:
- Utilized a VNA configured for one-port reflection coefficient measurement.
- Employed a frequency offset strategy, tuning the VNA receiver to a frequency slightly offset from the signal generator's output frequency.
- Implemented a narrow intermediate frequency bandwidth (IFBW) to minimize noise and out-of-band interference.
- Developed automated Windows-based software to control the measurement sequence, VNA parameters, and data acquisition.
Main Results:
- Successfully enabled accurate measurement of both magnitude and phase of the reflection coefficient for an active RF signal generator.
- Demonstrated the effectiveness of the frequency offset and narrow IFBW technique in mitigating self-interference.
- The developed software facilitated automated data capture and supported measurements at multiple output power levels.
Conclusions:
- The proposed method provides a robust solution for measuring the reflection coefficient of active RF signal generators.
- Accurate characterization of RF signal generators is achievable even under demanding active output conditions.
- The automated system enhances efficiency and enables comprehensive performance analysis across a range of operational parameters.
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