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Author Kroug, M.; Cherednichenko, S.; Merkel, H.; Kollberg, E.; Voronov, B.; Gol'tsman, G.; Hübers, H. W.; Richter, H.
Title NbN hot electron bolometric mixers for terahertz receivers Type Journal Article
Year 2001 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 11 Issue 1 Pages 962-965
Keywords NbN HEB mixers
Abstract Sensitivity and gain bandwidth measurements of phonon-cooled NbN superconducting hot-electron bolometer mixers are presented. The best receiver noise temperatures are: 700 K at 1.6 THz and 1100 K at 2.5 THz. Parylene as an antireflection coating on silicon has been investigated and used in the optics of the receiver. The dependence of the mixer gain bandwidth (GBW) on the bias voltage has been measured. Starting from low bias voltages, close to operating conditions yielding the lowest noise temperature, the GBW increases towards higher bias voltages, up to three times the initial value. The highest measured GBW is 9 GHz within the same bias range the noise temperature increases by a factor of two.
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Call Number Serial 312
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Author Cherednichenko, S.; Kollberg, E.; Angelov, I.; Drakinskiy, V.; Berg, T.; Merkel, H.
Title Effect of the direct detection effect on the HEB receiver sensitivity calibration Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 235-239
Keywords HEB, mixer, direct detection effect
Abstract We analyze the scale of the HEB receiver sensitivity calibration error caused by the so called “direct detection effect”. The effect comes from changing of the HEB parameters when whey face the calibration loads of different temperatures. We found that for HIFI Band 6 mixers (Herschel Space Observatory) the noise temperature error is of the order of 8% for 300K/77K loads (lab receiver) and 2.5% for 100K/10K loads (in HIFI). Using different approach we also predict that with an isolator between the mixer and the low noise amplifiers the error can be much smaller.
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Publisher Place of Publication Göteborg, Sweden Editor
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Call Number Serial 360
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Author Merkel, H.; Khosropanah, P.; Yagubov, P.; Kollberg, E.
Title A hot spot mixer model for superconducting phonone–cooled HEB far above the quasipartical band gap Type Conference Article
Year 1999 Publication Proc. 10th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 592-606
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Publisher Place of Publication Charlottesville, Virginia Editor
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Call Number Serial 292
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Author Merkel, H. F.; Khosropanah, P.; Sigfrid Yngvesson, K.; Cherednichenko, S.; Kroug, M.; Adam, A.; Kollberg, E.
Title An active zone small signal model for hot-electron bolometric mixers Type Conference Article
Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 55
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Publisher Place of Publication San Diego, CA, USA Editor
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Call Number RPLAB @ s @ losses_in_contacts_merkel Serial 320
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Author Khosropanah, P.; Merkel, H.; Yngvesson, S.; Adam, A.; Cherednichenko, S.; Kollberg, E.
Title A distributed device model for phonon-cooled HEB mixers predicting IV characteristics, gain, noise and IF bandwidth Type 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.
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Publisher Place of Publication University of Michigan, Ann Arbor, MI USA Editor
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Call Number Serial 893
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