SOLT

SOLT stands for Short-Open-Load-Through, a calibration technique used with vector network analyzers (VNAs) to remove systematic errors from S-parameter measurements. The method relies on measurements of four known standards to characterize the measurement channel and move the reference planes to the device under test.

In SOLT calibration, the two-port network is calibrated using four reference standards: a short circuit, an open circuit, a matched load, and a through connection between the two ports. By recording the responses of these standards, the VNA derives an error model that describes terms such as source match, reflection tracking, and transmission tracking. The resulting correction factors are applied to subsequent measurements, enabling the accurate extraction of the device under test’s true S-parameters.

SOLT is widely used in RF and microwave engineering for characterizing components and networks from low to microwave frequencies. It is valued for its relative simplicity and compatibility with coaxial and microstrip implementations, making it a common choice for routine VNA calibration. The accuracy of SOLT depends on the quality and stability of the reference standards, the proper implementation of the calibration procedure, and the assumption that the standards behave as ideal references within the measurement band.

Related methods include TRL (Through-Reflect-Line) calibration, which uses different reference standards. SOLT remains a foundational technique in modern VNA practice, enabling reliable, repeatable two-port measurements across a broad frequency range.