Conversion gain and noise of YBa/sub 2/Cu/sub 3/O/sub 7/ weak-link mixers

Author

Butler, D.P. ; Wang, J. ; Bhandari, A. ; Celik-Butler, Z.

Author_Institution

Dept. of Electr. Eng., Southern Methodist Univ., Dallas, TX, USA

Volume

3

Issue

1

fYear

1993

fDate

3/1/1993 12:00:00 AM

Firstpage

2269

Lastpage

2272

Abstract

Microwave mixing and parametric conversion in YBa/sub 2/Cu/sub 3/O/sub 7/ microbridges were investigated. The devices have been operated as down-converters, converting a 20-GHz radio frequency to a 1.5-GHz intermediate frequency under the action of an 18.5-GHz local oscillator. The microbridges were fabricated both as granular films on MgO substrates possessing grain boundary weak links and as epitaxial films deposited over substrate steps in LaAlO/sub 3/ substrates. The authors have measured conversion gains as high as -8+or-4 dB when mixing on the nonlinear resistive (superconducting-normal) transition and as high as -30 to -40 dB when parametrically converting via the nonlinear inductance of the bridge at bias currents less than the critical current. Output referred noise powers as low as -206 dB/Hz (3*10/sup -21/ W/Hz) have been measured. In some samples, noise switching events were observed.<>

Keywords

barium compounds; electron device noise; high-temperature superconductors; microwave parametric devices; mixers (circuits); superconducting junction devices; superconducting microwave devices; yttrium compounds; HTSC; LaAlO/sub 3/; MgO substrates; YBa/sub 2/Cu/sub 3/O/sub y/ microbridges; conversion gains; down-converters; epitaxial films; grain boundary weak links; granular films; local oscillator; noise powers; noise switching events; parametric conversion; weak-link mixers; Current measurement; Frequency conversion; Grain boundaries; Inductance measurement; Local oscillators; Radio frequency; Substrates; Superconducting device noise; Superconducting films; Superconducting microwave devices;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.233551

Filename

233551