Flux flow oscillators for sub-mm wave integrated receivers

Author

Koshelets, V.P. ; Shitov, S.V. ; Shchukin, A.V. ; Filippenko, L.V. ; Dmitriev, P.N. ; Vaks, V.L. ; Mygind, J. ; Baryshev, A.M. ; Luinge, W. ; Golstein, H.

Author_Institution

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

Volume

9

Issue

2

fYear

1999

fDate

6/1/1999 12:00:00 AM

Firstpage

4133

Lastpage

4136

Abstract

The results of a detailed study of the microwave linewidth of Nb-AlO/sub x/-Nb flux flow oscillators (FFO) are presented. The dependence of the FFO linewidth on the junctions parameters has been measured by using an improved technique based on harmonic mixing in the frequency range 250-600 GHz. Experimental data are compared with theoretical estimates to evaluate the influence of the possible mechanisms responsible for the broadening of the FFO linewidth. The origins of the increased linewidth at the transition from the resonant to the "pure" flux-flow regime are discussed. The results of the linewidth measurements for the FFO locked to an external synthesizer via a wideband feedback loop are presented. The possibility of phase locking of the Josephson oscillator has been demonstrated experimentally. A FFO linewidth as low as 3.3 kHz (determined by the resolution bandwidth of the spectrum analyzer) has been measured at 310 GHz; it is far below the fundamental level given by shot and thermal noise of the free-running tunnel junction.

Keywords

aluminium compounds; flux flow; microwave oscillators; niobium; phase locked oscillators; submillimetre wave receivers; superconducting device noise; superconducting microwave devices; superconductor-insulator-superconductor devices; 250 to 600 GHz; Josephson oscillator; Nb-AlO-Nb; Nb-AlO/sub x/-Nb tunnel junction; flux flow oscillator; harmonic mixing; microwave linewidth; noise temperature; phase locking; sub-MM wave integrated receiver; Bandwidth; Estimation theory; Feedback loop; Frequency measurement; Microwave oscillators; Noise measurement; Resonance; Spectral analysis; Synthesizers; Wideband;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/77.783935

Filename

783935