Patent ID: 6882160

Claim:
For use in an environment in which a test set is used to connect an N-port DUT to an M-port VNA, where N>M, a method for efficiently performing a full N-port calibration using the M-port VNA, comprising: a) performing multiple M-port calibrations at a DUT plane, defined between the test set and the N-port DUT, to thereby determine error coefficients for each of the N ports in the DUT plane, said error coefficients including reflectometer error coefficients; b) determining an uncorrected off-state reflection coefficient, for each of the N ports at the DUT plane, by connecting various pairs of ports k and q (at the DUT plane) together and measuring the uncorrected off-state reflection coefficient Skkthru with port q turned off using the test set, and measuring the uncorrected off-state reflection coefficient Sqqthru with port k turned off using the test set; c) determining a corrected off-state reflection coefficient (Γ), for each of the N ports at the DUT plane, based on the reflectometer error coefficients determined at step (a) and the reflection coefficients determined at step (b); d) determining an off-state impedance (Z) for each of the N ports at the DUT plane, based on the corrected off-state reflection coefficients (Γ) determined at step (c), e) performing multiple M-port S-parameter measurements of the N-port DUT, and correcting the measured S-parameters using the error coefficients determined at step (a), to thereby determine all S-parameters required to produce an N×N scattering matrix; f) re-referencing each M 2 set of S-parameters determined at step (e) to the off-state impedances Z k1 , . . . , Z km determined at step (d), where k 1 , . . . , km, are the M-ports involved in a corresponding M-port S-parameter measurement; g) combining the re-referenced S-parameters determined at step (f) into an N×N matrix; and h) re-referencing the N×N matrix to a desired calibration reference impedance.