Multiport S-parameter measurements of linear circuits with open ports

A simple technique to measure the S-parameters of a linear multiport with a two-port network analyzer is evaluated. Just two probes and a single specimen are required. All two-port combinations are measured with the other ports left open. Special care was taken to estimate the maximum measurement uncertainties and to identify critical parameter values. Results can be further improved by using a simplified weighting scheme or by correcting for open-port capacitances. The technique is especially suited for wafer probes.