Variable transmission lines: Structure and compact modeling

The concept of Variable Transmission Lines (VTL) offers digital tuning of transmission line characteristics to compensate for process variations and parasitic modeling uncertainties. VTL structures and models enabling robust silicon-based millimeter-wave IC design are proposed along with a compact model for their efficient simulation. The developed compact models have been successfully integrated into a standard silicon-foundry design kit to enable, for the first time, circuit-level simulations with parametric VTL. Several VTL evaluation structures have been fabricated in IBM 32nm CMOS SOI technology. Measurement results up to 65GHz are presented to evaluate the proposed structures and their models.