The "unknown thru" calibration advantage

The “unknown thru” calibration method was proposed by Andrea Ferrero and Umberto Pisani in 1992. It is one of many variations possible under the general theory of vector network analyzer, VNA, calibration. It is well suited for calibrating a VNA system with immobile or untouchable test ports, such as a wafer probe station. It is also an ideal calibration method for measuring non-insertables, odd shape and multiport devices. This paper will provide a quick overview of the theory, uncertainty analysis and show some examples of how this calibration method can he used to improve measurement accuracy and consistency.