Mutual-inductance-free X-topology model synthesis of multi-conductor lines accounting for floating ground references

This paper proposes an original mutual-inductance-free broadband equivalent model synthesis methodology for multi-conductor systems. The proposed analysis can be understood as an extension of Bartlett bisection theorem with the concept of even (common) and odd (differential) excitation states. The contribution renders possible bridging mixed-mode S-parameter representation with distributed wideband equivalent circuit model synthesis of differential and common-mode circuits. The synthesis methodology accounts for local ground distribution and nonuniform patterning. The validity of the modeling and experimental characterization approach is demonstrated by application to two-port and four-port multi-conductor structures. Comparison between extracted broadband synthesis model and measurement for frequency up to 110 GHz shows excellent agreement, with passive-guaranteed and causal equivalent circuit representations. It is demonstrated for multi-conductor systems, that inductive couplings can be accurately represented in a wide frequency range without use of mutual term components.