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Author Shurakov, Alexander; Tong, Edward; Blundell, Raymond; Gol'tsman, Gregory openurl 
  Title Microwave stabilization of HEB mixer by a microchip controller Type (up) Conference Article
  Year 2012 Publication IEEE MTT-S international microwave symposium digest Abbreviated Journal  
  Volume Issue Pages 1-3  
  Keywords HEB mixer stability, microwave injection, Allan variance, Allan time  
  Abstract The stability of a Hot Electron Bolometer (HEB) mixer can be improved by the use of microwave injection. In this article we report a refinement of this approach. We introduce a microchip controller to facilitate the implementation of the stabilization scheme, and demonstrate that the feedback loop effectively suppresses drifts in the HEB bias current, leading to an improvement in the receiver stability. The measured Allan time of the mixer's IF output power is increased to > 10 s.  
  Address Montreal, QC, Canada  
  Corporate Author Thesis  
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  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 857  
Permanent link to this record
 

 
Author Khosropanah, P.; Merkel, H.; Yngvesson, S.; Adam, A.; Cherednichenko, S.; Kollberg, E. openurl 
  Title A distributed device model for phonon-cooled HEB mixers predicting IV characteristics, gain, noise and IF bandwidth Type (up) Conference Article
  Year 2000 Publication Proc. 11th Int. Symp. Space Terahertz Technol. Abbreviated Journal  
  Volume Issue Pages 474-488  
  Keywords HEB mixer numerical model, diffusion cooling channel, diffusion channel, distributed HEB model, distributed model  
  Abstract A distributed model for phonon-cooled superconductor hot electron bolometer (HEB) mixers is given, which is based on solving the one-dimensional heat balance equation for the electron temperature profile along the superconductor strip. In this model it is assumed that the LO power is absorbed uniformly along the bridge but the DC power absorption depends on the local resistivity and is thus not uniform. The electron temperature dependence of the resistivity is assumed to be continuous and has a Fermi form. These assumptions are used in setting up the non-linear heat balance equation, which is solved numerically for the electron temperature profile along the bolometer strip. Based on this profile the resistance of the device and the IV curves are calculated. The IV curves are in excellent agreement with measurement results. Using a small signal model the conversion gain of the mixer is obtained. The expressions for Johnson noise and thermal fluctuation noise are derived. The calculated results are in close agreement with measurements, provided that one of the parameters used is adjusted.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication University of Michigan, Ann Arbor, MI USA Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 893  
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Author Ynvesson, K. Sigfrid; Kollberg, Erik L. openurl 
  Title Optimum receiver noise temperature for NbN HEB mixers according to standard model Type (up) Conference Article
  Year 1999 Publication Proc. 10th Int. Symp. Space Terahertz Technol. Abbreviated Journal  
  Volume Issue Pages 566-582  
  Keywords HEB mixer model, standard model, electro-thermal feedback, self-heating parameter, heating efficiency  
  Abstract  
  Address  
  Corporate Author Thesis  
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  Series Editor Series Title Abbreviated Series Title  
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  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 895  
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Author Klapwijk, T. M.; Barends, R.; Gao, J. R.; Hajenius, M.; Baselmans, J. J. A. openurl 
  Title Improved superconducting hot-electron bolometer devices for the THz range Type (up) Conference Article
  Year 2004 Publication Proc. SPIE Abbreviated Journal Proc. SPIE  
  Volume 5498 Issue Pages 129-139  
  Keywords HEB mixer distributed model, numerical model  
  Abstract Improved and reproducible heterodyne mixing (noise temperatures of 950 K at 2.5 THz) has been realized with NbN based hot-electron superconducting devices with low contact resistances. A distributed temperature numerical model of the NbN bridge, based on a local electron and a phonon temperature, has been used to understand the physical conditions during the mixing process. We find that the mixing is predominantly due to the exponential rise of the local resistivity as a function of electron temperature.  
  Address  
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  Area Expedition Conference  
  Notes Invited talk, Recommended by Klapwijk Approved no  
  Call Number Serial 912  
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Author Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Golts'man, G.; Gershenzon, E.; Voronov B. url  openurl
  Title Superconductive NbN hot-electron bolometric mixer performance at 250 GHz Type (up) Conference Article
  Year 1996 Publication Proc. 7th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 7th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages 331-336  
  Keywords NbN HEB mixers  
  Abstract Thin film NbN (<40 A) strips are used as waveguide mixer elements. The electron cooling mechanism for the geometry is the electron-phonon interaction. We report a receiver noise temperature of 750 K at 244 GHz, with / IF = 1.5 GHz, Af= 500 MHz, and Tphysical = 4 K. The instantaneous bandwidth for this mixer is 1.6 GHz. The local oscillator (LO) power is 0.5 1.tW with 3 dB-uncertainty. The mixer is linear to 1 dB up to an input power level 6 dB below the LO power. We report the first detection of a molecular line emission using this class of mixer, and that the receiver noise temperature determined from Y-factor measurements reflects the true heterodyne sensitivity.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 945  
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