A Fixed-Tuned SIS Mixer with Ultra-Wide-Band IF and Quantum-Limited Sensitivity for ALMA Band 3 (84-116 GHz) Receivers
S.-K. Pan, Anthony R. Kerr, M.W. Pospieszalski, E. F. Lauria, W. K. Crady, Nathaniel Horner, Sivasankaran Srikanth, Eric W. Bryerton, Kamaljeet Saini, Stephane M. X. Claude, Rey Chin, Philip Dindo, G. Rodrigues, Dennis Derdall, J. Z. Zhang, A. W. Lichtenberger
Abstract
Abstract- This paper describes an 84-116 GHz Nb/Al-oxide/Nb SIS mixer with multi-octave IF bandwidth and quantum-limited sensitivity. The mixer can be integrated with a three-stage 4-12 GHz HFET preamplifier or fitted with a coaxial connector for operation with an external isolator and IF amplifier. An 84-116 GHz receiver using the mixer with an integrated 4-12 GHz HFET preamplifier has a double sideband noise temperature of 16-20 K ( 3 to 4 h</kB) over most of the IF band. Analysis of the mixer-preamp using Tucker=s theory shows good agreement with measurements. The mixer is easy to build and is being used as a building block for the Band 3 sideband-separating receivers for the Atacama Large Millimeter Array (ALMA)**. With minor modifications, this mixer design can be scaled to other ALMA bands. I