A V-Band Wafer Probe

In this paper the design and development of a V-band (50-75 GHz) probe is presented. The V-band probe must have a waveguide input, since commercially available coaxial cable has overmoding present above 65 GHz. Design goals: ¿ Frequency coverage 50-75 GHz ¿ Insertion loss better than 4 dB ¿ Correctable performance: (|S11| - |S21| ¿ 5dB) ¿ Footprint GSG (ground-signal-ground) ¿ Pitch availability 50-250 microns ¿ Biasing ability An insertion loss of less than 4 dB at 75 GHz and correctable performance is desired. Correctable performance implies that there is adequate separation between insertion loss and return loss, allowing meaningful data to be obtained for deriving the error correction model. A difference of 5 dB has been found to give useable results, and is expressed as |S11 - |S21| ¿ 5dB. The coplanar probe lip will be a ground-signal-ground configuration, with pitch selection available from 50 to 250 microns. The signal line must be able to be biased with respect to the ground contacts for on-wafer deviced characterization. The input is to be a V-band rectangular waveguide with WR-15 flanges.