A non-50 & omega;-RMCL transition designed for on-chip measurement in the 0-170 GHz frequency range

The authors present the design of a rectangular micro-coaxial line (RMCL) to ground-to-ground (GSG) probe pad transition for broadband millimetre-wave (mmW) probe testing. The proposed transition is designed to effectively operate across the frequency range from DC to 170 GHz, providing the capability to convert non-50 & omega; RMCL ports to 50 & omega; GSG ports. To validate the design methodology, the back-to-back model of the transition is fabricated and experimentally characterised. The fabricated transition exhibits a remarkable return loss exceeding 18 dB, along with an insertion loss below 0.4 dB within the frequency span of 0-75 GHz. With this transition, on-chip measurement of non-50 & omega; ultra-wideband millimetre-wave chips becomes feasible.