Scattering Parameter Characterization of a Novel Four-Port Fixture Using Time Domain Gating and Mason’s Gain Formula

Modern electronic devices comprise a complex structure of interconnected components, and signals passing through various fixtures are prone to attenuation and distortion across various frequencies. This paper presents a novel four-port fixture characterization scheme that converts the S-parameters of a 2x-Thru structure into time-domain reflectometry data. This data is then separated into the two sides of the fixture via time-domain gating. After the remaining S-parameters are calculated using Mason’s gain formula, fixture effects are removed through a de-embedding process involving matrix operations to yield the S-parameters of the device under test. The efficacy of the proposed scheme is demonstrated through comparison with the industry-standard automatic fixture removal (AFR) algorithm.