Differential S-Parameter De-embedding for 8-Port Network

Compared to 4-port de-embedding, 8-port de-embedding is much more challenging due to the presence of crosstalk terms in both the differential mode and the common mode. Using the 2^nd order mixed-mode concept, this work proposes an 8-port smart fixture de-embedding (SFD) method. The proposed method neglects modal conversion terms by requiring balanced and symmetrical designs. Analysis showed that this approximation generally has negligible impact on the de-embedded differential results with careful test fixture design.