Analytical characterization of S-matrix reconstruction transforms on multiport networks

S-matrix reconstruction transforms are based on two stages of matrix transformation to remove the mismatch-induced errors. Over the years, these transforms are widely used in measurements of multiport devices using two-port vector network analyzer, especially for noncoaxial applications because high-quality matched loads are hardly accessible. In this paper, analytical error analysis of the S-matrix reconstruction transforms is performed to show that three S-matrix transforms have the exact same accuracy. Additionally, the concept of acquiring stationary solutions is presented to improve the accuracy of reconstructing S-matrix with strongly reflecting auxiliary terminations. For noncoaxial measurements, strongly reflecting termination, such as a short-circuited or an open-circuited transmission line is more repeatable, reliable and economical than terminations with loss like resistors. Consequently, the use of strongly reflecting auxiliary terminations is speculated to ease noncoaxial multiport measurements.