Title :
Hybrid integration of a Josephson series array and a 10 GHz planar oscillator
Author :
Hebrank, Franz X. ; Vollmer, E. ; Funck, T. ; Kohlmann, J. ; Gutmann, P. ; Niemeyer, J.
Author_Institution :
Phys. Tech. Bundesanstalt, Braunschweig, Germany
fDate :
4/1/1997 12:00:00 AM
Abstract :
A computer-controlled Josephson voltage standard has been developed comprising the hybrid integration of a planar oscillator and a Josephson series array. A 10 GHz voltage controlled oscillator has been frequency-stabilized to a reference frequency by a phase-locked loop. A series array has been designed and fabricated in Nb/Al2O3/Nb technology. To obtain quantized voltage steps with a drive frequency of 10 GHz, the critical current density of the Junctions is reduced to below 2 A/cm2 by variation of the oxidation parameters. The hybrid integration of a Josephson circuit with a planar MESFET oscillator produced quantized voltage steps up to 980 mV with a step width of 2 μA
Keywords :
aluminium compounds; critical current density (superconductivity); hybrid integrated circuits; measurement standards; microwave oscillators; niobium; phase locked loops; physical instrumentation control; superconducting junction devices; voltage measurement; voltage-controlled oscillators; 10 GHz; 10 GHz planar oscillator; 2 muA; 980 mV; Josephson series array; Nb-Al2O3-Nb; Nb/Al2O3/Nb technology; computer-controlled Josephson voltage standard; critical current density; drive frequency; hybrid integration; phase-locking; planar MESFET oscillator; planar oscillator; quantized voltage steps; reference frequency; series array; voltage controlled oscillator; Frequency; MMICs; Microstrip; Microwave antenna arrays; Microwave circuits; Microwave oscillators; Niobium; Standards development; Voltage; Voltage-controlled oscillators;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
