Standard Protocol for De-Embedding S-Parameter Calibration Data on Test Benches
Stripping test fixture phase delay and magnitude loss from raw vector network analyzer measurements ensures true S-parameter extraction.
SOLT
Meaning
Vector network analyzer calibration procedures use a set of four known physical standards to eliminate systematic measurement errors. Measurement technicians use solt to define the reference plane at the ends of coaxial cables before testing RF boards.
Calibration Standard
Short, open, load, and thru structures are measured sequentially to calculate the error terms of the test system. The known electrical behavior of these standards allows the analyzer to calculate and subtract the effects of cables and internal switches. This process is highly dependent on the quality and wear of the calibration kit connectors.
Systematic Error
Random noise and thermal drift are not corrected by this procedure, but static tracking and source match errors are removed. The correction algorithm converts raw measurement values into highly accurate scattering parameters. These corrected values are essential for verifying trace impedances on high-speed substrates.
Frequency Limit
High frequency tests can suffer from phase errors because of the physical models used to define the open and short standards. The capacitive and inductive behaviors of these standards must be modeled accurately in the instrument software to ensure valid results above twelve gigahertz. This limitation makes the technique less suitable for millimetre-wave on-wafer probing where other methods are preferred.