Investigation of On-Wafer TRL Calibration Accuracy Dependence on Transitions and Probe Positioning

This paper presents the effects of various transition types from the measurement plane to the reference plane in TRL calibration and probe positioning effects for on wafer measurements of CPW based devices. Fourteen different transition types, with direct, linear and exponential transitions, including 3 different variations of ground-signal-ground (GSG) spacing are examined. To observe the performance of the transitions, simple CPW transmission lines of different characteristic impedances are fabricated using standard lithography techniques on glass substrate and S-parameters are measured in 4.5-20 GHz band. Results are compared with electromagnetic simulations. The effects of probe misplacement along the lateral and horizontal axis are also investigated