Design and On-Wafer Measurement of a W-Band Via-Less CPW RF Probe Pad to Microstrip Transition

A very wide band via-less coplanar waveguide RF probe pad to microstrip transition is presented. The simulation with Agilent´s Momentum (MOM) shows that a 3 dB bandwidth of 173% can be achieved from 10GHz to 110GHz with an average loss of 0.4dB, and 0.2dB at 70GHz. The fabrication was done on 100¿m thick high resistivity silicon wafer, and two measurement methods were used to obtain the s-parameters of the transition. Measured results show that the insertion loss has an average value of 0.4dB from 40GHz to 100GHz, with the return loss better than 13dB.