A non‐50 Ω‐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 Ω RMCL ports to 50 Ω 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 Ω ultra‐wideband millimetre‐wave chips becomes feasible.