A NEW 10-V ARRAY OF JOSEPHSON-JUNCTIONS BASED ON LOW-FREQUENCY DESIGNS SCALED UP TO 94 GHZ

A novel approach is described for the design of improved coupling of m illimeter-waves in a 10-V array of Josephson junctions, In this approa ch, microwave structures were fabricated and tested in the range 2.8 G Hz to 3.6 GHz, and a scaling calculation was then used to transform th em to 94 GHz. By optimizing the trade-off between antenna size and eff iciency, it was possible to make more space available on the device ch ip to increase the number of Josephson junctions, Simulation results s howed that the optimal antenna is a short double-fin-line type, This a ntenna type allowed us to fabricate a Josephson junction array that ha d 25944 Nb/Al-AlOx/Nb junctions, For this new array, zero-crossing ste ps were observed up to 18.5 V, The new array was then successfully use d to calibrate a Zener voltage standard that had a 10-V output.