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/spl mu/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.