Title :
Parallel biased SIS-arrays for mm wave mixers: main ideas and experimental verification
Author :
Ermakov, An.B. ; Koshelets, V.P. ; Kovtonyuk, S.A. ; Shitov, S.V.
Author_Institution :
Inst. of Radio Eng. & Electron., Acad. of Sci., Moscow, USSR
fDate :
3/1/1991 12:00:00 AM
Abstract :
The possibility of overcoming the main drawbacks of the traditional series arrays by parallel connection of the SIS (superconductor-insulator-superconductor) junctions for DC and IF are demonstrated experimentally. The proposed mixing elements avoid the influence of the junction nonuniformity in the array, provide the optimal matching on both RF input and IF output, and tune out junction capacitance. Experimentally tested arrays contained up to eight high-quality Nb-AlOx-Nb junctions with Rn=20-70 Ω at junction area 8÷14 μm 2. The best values of Tr (SSB) were measured to as low as 5 K on the mixer cold input flange in the 45-55-GHz bandwidth at an ambient temperature of 4.2 K. A mixer gain of up to 10 dB was obtained. The gain values were limited by bias stability at very high or even negative array output impedance. An experimental receiver noise temperature (SSB) of less than 20 K has been achieved
Keywords :
aluminium compounds; mixers (circuits); niobium; solid-state microwave circuits; superconducting junction devices; 20 to 70 ohm; 4.2 K; 95 to 55 GHz; DC; IF; Nb-AlOx-Nb; bias stability; junction capacitance; junction nonuniformity; mixer cold input flange; mixer gain; mixing elements; mm wave mixers; negative array output impedance; optimal matching; parallel-biased SIS arrays; receiver noise temperature; Amplitude modulation; Capacitance; Flanges; Gain measurement; Josephson junctions; Optimal matching; Radio frequency; Superconducting devices; Temperature; Testing;
Journal_Title :
Magnetics, IEEE Transactions on
