Generalized indirect S-parameter measurement method of n-ports circuit using T-parameter of (m, n)-ports fixture

摘要

In this paper, the minimum number of calibration loads sets and the degrees of freedom of T-parameter of a fixture for the indirect estimation of S-parameters of a device under test (DUT) are presented. Specifically, the case wherein the number of measurement ports (m) is greater than the number of ports of the DUT (n) is investigated. The T-parameters of the (m, n)-port fixture are obtained by connecting a known-loads set instead of the DUT and measuring the S-parameters between the remaining ports. Subsequently, the S-parameters of the DUT can be obtained by removing the characteristics of the fixture from the measured values. The advantage of obtaining the T-parameters instead of the S-parameters of the fixture is that the estimation equations become linear equations.