Full-wave-based transmission-line model for lossy-substrate multiconductor interconnects

A full-wave-based modal analysis is used for simulating a multiconductor coplanar waveguide (CPW) over a selectively etched lossy silicon substrate. Propagating modes, which are similar to the classic 'common' and 'differential' modes, are extracted, and circuit theory energy relationships are used for the determination of transmission-line model parameters. A time-frequency domain technique is employed for implementing the transmission-line model within a circuit simulator. The model is used to study the effect of etching the dielectric and the substrate for a two-conductor CPW line. The simulation results show that etching both the dielectric and the lossy substrate improves the loss and dispersion characteristics of the CPW line. Copyright (c) 2007 John Wiley & Sons, Ltd.