Optimization of input impedance and mechanism of noise suppression in a DC SQUID RF amplifier

Author

Tarasov, M. ; Ivanov, Z.

Author_Institution

Inst. of Radio Eng. & Electron., Acad. of Sci., Moscow, Russia

Volume

6

Issue

2

fYear

1996

fDate

6/1/1996 12:00:00 AM

Firstpage

81

Lastpage

86

Abstract

The optimal input impedance and noise of a DC SQUID RF amplifier at frequencies of the order of 1 GHz with a resonant input matching circuit have been studied analytically, numerically, and experimentally. A model for noise temperature and power gain has been developed for the practical resonant input tank circuit. A new effect of the output noise increasing or decreasing with changing the sign of voltage-to-flux transfer coefficient has been observed experimentally and explained analytically. The different values of noise temperature for the opposite dV/d/spl Phi/ values have been interpreted using a model with partially correlated current and voltage noise sources. The equivalent layout for optimal input matching of a SQUID amplifier comprising series and parallel resonant circuits has been presented. Using such a matching circuit and SIS junction as a signal source the SQUID amplifier noise temperature about 1 K has been measured at 1.1 GHz.

Keywords

SQUIDs; UHF amplifiers; impedance matching; superconducting device noise; superconducting device testing; superconducting microwave devices; 1.1 GHz; DC SQUID RF amplifier; SIS junction signal source; input impedance; noise suppression; noise temperature; parallel resonant circuits; partially correlated current; power gain; resonant input matching circuit; series resonant circuits; voltage noise sources; voltage-to-flux transfer coefficient; Circuit noise; Frequency; Impedance matching; Noise measurement; RLC circuits; Radiofrequency amplifiers; Resonance; SQUIDs; Temperature; Voltage;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.506687

Filename

506687