Vector Network Analyzers Using CMT VNA Software

Along with defining a calibration standard by a calibration model or data, the standard should also be assigned a specific class. One calibration standard may belong to one class This class assignment is crucial for specifying properties such as the calibration method and the role of the standard in calibration.

To simplify the calibration process and guide users in selecting the correct standards, calibration families organize standards into logical groups, aligning with the steps necessary for accurate S-parameter measurements.

The two main families of calibration classes—SOLT and TRL—define which standards are required at each calibration step, ensuring consistency and reducing errors for a smoother and more reliable calibration process.

SOLT Family Classes

The SOLT family is based on the use of Short, Open, Load, and Thru standards, commonly used in traditional calibration methods.

In SOLT calibration, the process typically involves two one-port calibrations followed by a thru measurement. The thru connection may include either a defined thru (with a known definition) or unknown thru (with no predefined definition). The simplest definition of a thru standard is a flush thru, an ideal zero-length connection between two analyzer ports.

The following table lists the SOLT family classes and the recommended settings for each calibration method.

TRL Family Classes

The TRL family is based on Thru, Reflect, and Line standards, commonly used in more advanced calibration scenarios, especially at higher frequencies.

TRL calibration requires measuring two two-port standards with identical structures but different electrical lengths, along with a high-reflection standard. Unlike SOLT, TRL operates over a frequency range where the phase difference between the thru and line standards is at least 20 degrees.

The following table lists the TRL family classes and the recommended settings for each calibration method.