SIS mixer research. Final technical report, 1 Feb 89-13 May 90

Technical Report · Wed Oct 31 23:00:00 EST 1990

OSTI ID:5688600

Lichtenberger, A W; Feldman, M J

Theoretica and experimental research has been conducted to elucidate the basic physics behind the properties of superconductor-insulator-superconductor (SIS) tunnel junction receiving devices. The properties of an SIS mixer using a slightly nonideal junction, with finite LO power, were determined by analytic expansion of the equations of the quantum theory of mixing. The resulting equations have a particularly simple form. The minimum noise temperature is controlled by the leakage current of the junction. Even the most nearly ideal junctions made today require a considerable LO for best sensitivity; nevertheless, even a comparatively large leakage current allows mixer noise to be only a small factor above the quantum limit. The saturation properties of SIS mixers subjected to broad-band thermal noise obey the equations derived for monochromatic saturating signals. The Josephson junction tuning inductor was analyzed with the conclusion that such a device is not feasible with present fabrication techniques. Computer calculations using synthetic SIS junction I-V characteristics predicted the performance of an optimized receiver over its entire operating frequency range. Many aspects of the operation of SIS mixers were clarified and unexpected new phenomena were predicted. A 'photon picture' interpretation of the quantum theory of mixing is in the early stages of development. Niobium nitride edge junctions with excellent current-voltage characteristics were fabricated using novel barrier formation processes. The role of surface damage in the quality of NbN edge junction electrical characteristics was investigated and unexpected results were obtained.

• Research Organization: Virginia Univ., Charlottesville, VA (USA). Dept. of Electrical Engineering
• OSTI ID: 5688600
• Report Number(s): AD-A-230167/9/XAB; UVA--525704/EE91/101; CNN: AFOSR-89-0233
• Country of Publication: United States
• Language: English

Related Subjects

426001* -- Engineering-- Superconducting Devices & Circuits-- (1990-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPUTER CALCULATIONS
CURRENTS
DAMAGE
ELECTRIC COILS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
ELECTRICAL EQUIPMENT
ELECTRICAL PROPERTIES
EQUATIONS
EQUIPMENT
EXPANSION
FABRICATION
JOSEPHSON JUNCTIONS
JUNCTIONS
LEAKAGE CURRENT
MECHANICS
NIOBIUM COMPOUNDS
NITRIDES
NITROGEN COMPOUNDS
NOISE
OPTIMIZATION
PHYSICAL PROPERTIES
PHYSICS
PNICTIDES
QUANTUM MECHANICS
REFRACTORY METAL COMPOUNDS
RESEARCH PROGRAMS
SATURATION
SUPERCONDUCTING JUNCTIONS
SUPERCONDUCTIVITY
SURFACES
TRANSITION ELEMENT COMPOUNDS
TUNNEL EFFECT