Characterizations of asymmetric fixtures with a two-gate approach

A technique for extracting asymmetric fixtures from a through standard and de-embedding the fixture effects from the composite measurement of DUT and fixture combination has been proposed. The technique consists of: (1) building a through standard which is the cascaded combination of the two fixtures. The two fixtures can be asymmetric in return loss but are symmetric in insertion loss and have the same electrical lengths, (2) extracting the fixture S-parameters from the measurement of the through standard, (3) de-embedding the fixture effects from the composite measurement and characterizing only the DUT. The 2-port single-ended case was investigated first and then we extended the technique to 4-port mixed mode. Deductions for extracting the S-parameters of the two fixtures are described in details and the extraction result was validated with simulations and measurements.