OPTIMIZED 1 V AND 10 V JOSEPHSON SERIES ARRAYS

Using a modified fabrication method and a detailed design investigatio n we have been able to optimize the array circuits for the Josephson v oltage standard and to solve the trapped flux problem. Even in very lo ng arrays (4800 Junctions in a single stripline) a yield of 1 mV per j unction could be achieved, The microwave power in the range from 70 GH z to 73 GHz required for stable operation of 1 V and 10 V circuits cou ld be reduced to approximately 1 mW and 10 mW (antenna input), respect ively. The best results at 10 V were obtained with circuits of 13 924 junctions arranged in 4 microwave paths connected in parallel. Excelle nt calibration conditions were maintained for current densities of abo ut 10 A/cm(2) for which the ratio of operating frequency to plasma fre quency is increased to six.