On-Chip technology independent 3-d models for millimeter-wave transmission lines with bend and gap discontinuity

Abstract

Although the discontinuity structures in the microstrip transmission lines such as a gap and bend have been largely studied, the three-dimensional edge effects, skin effects and metal losses have hardly been analyzed. In this paper, modeling of transmission line with bend and gap discontinuity with equation based process technology independent method are developed. The effect of the signal layer thickness is fully included in the model. Gap model is verified with EM simulation and implemented in BiCMOS technology on Silicon substrate. The bend is modeled with transmission line with effective length for the discontinuity area, and the equations have been generated. The bend model is compared with EM simulations, existing bend model generated with curve-fitted method and measured results. Gap and bend are enabled as library device in a 0.13 μm SiGe BiCMOS process design kit. Both bend and gap device have a scalable layout pattern and a schematic symbol, which allows users to choose them with different dimensions and metal stacks. In addition, the models can be migrated into other process technologies with different metal options. Very good match have been achieved among model, EM simulation and measurements for different process technologies and metal stacks.