An Approximate Closed-Form Transfer Function Model for Multiconductor Transmission Lines

This brief presents an intuitive, simple, and widely applicable approximate closed-form transfer function model for multiconductor transmission lines (MTLs). Rigorous closed-form transfer functions are derived from the telegrapher's equation and approximated for a wide range of MTLs that satisfy validity conditions. Theoretical error bounds are also proposed and tightly estimate the approximation errors. The approximate formulas are simple yet accurate, and can be intuitively interpreted by a simple voltage-controlled voltage source circuit model. In demonstration, we show that the proposed model allows designers intuitively to understand and accurately to analyze complex MTLs.