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Author Merkel, H. F.; Yagoubov, P. A.; Kroug, M.; Khosropanah, P.; Kollberg, E. L.; Gol’tsman, G. N.; Gershenzon, E. M.
Title Noise temperature and absorbed LO power measurement methods for NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies Type Conference Article
Year (up) 1998 Publication Proc. 28th European Microwave Conf. Abbreviated Journal Proc. 28th European Microwave Conf.
Volume 1 Issue Pages 294-299
Keywords NbN HEB mixers
Abstract In this paper the absorbed LO power requirements and the noise performance of NbN based phonon-cooled hot electron bolometric (HEB) quasioptical mixers are investigated for RF frequencies in the 0.55-1.1 range The minimal measured DSB noise temperatures are about 500 K at 640 GHz, 600 K at 750 GHz, 850 K at 910 GHz and 1250 K at 1.1 THz. The increase in noise temperature at 1.1THz is attributed to water absorption. The absorbed LO power is measured using a calorimetric approach. The results are subsequently corrected for lattice heating. These values are compared to results of a novel one dimensional hot spot mixer models and to a more traditional isotherm method which tends to underestimate the absorbed LO power for small bias powers. Typically a LO power between 50nW and 100nW is needed to pump the device to the optimal operating point.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference 28th European Microwave Conference
Notes Approved no
Call Number Serial 1580
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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 (up) 1999 Publication Proc. 10th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 592-606
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Corporate Author Thesis
Publisher Place of Publication Charlottesville, Virginia Editor
Language Summary Language Original Title
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Area Expedition Conference
Notes Approved no
Call Number Serial 292
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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 (up) 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
Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 893
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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 (up) 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal
Volume Issue Pages 55
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Corporate Author Thesis
Publisher Place of Publication San Diego, CA, USA Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
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Area Expedition Conference
Notes Approved no
Call Number RPLAB @ s @ losses_in_contacts_merkel Serial 320
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Author Cherednichenko, S.; Kroug, M.; Khosropanah, P.; Adam, A.; Merkel, H.; Kolberg, E.; Loudkov, D.; Voronov, B.; Gol'tsman, G.; Richter, H.; Hübers, H. W.
Title A broadband terahertz heterodyne receiver with an NbN HEB mixer Type Conference Article
Year (up) 2002 Publication Proc. 13th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 13th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 85-95
Keywords NbN HEB mixers
Abstract We present a broadband and low noise heterodyne receiver for 1.4-1.7 THz designed for the Hershel Space Observatory. A phonon- cooled NbN HEB mixer was integrated with a normal metal double- slot antenna and an elliptical silicon lens. DSB receiver noise temperature Tr was measured from 1 GHz through 8GHz intermediate frequency band with 50 MHz instantaneous bandwidth. At 4.2 K bath temperature and at 1.6 THz LO frequency Tr is 800 K with the receiver noise bandwidth of 5 GHz. While at 2 K bath temperature Tr was as low as 700 K. At 0.6 THz and 1.1 THz a spiral antenna integrated NbN HEB mixer showed the receiver noise temperature 500 K and 800 K, though no antireflection coating was used in this case. Tr of 1100 K was achieved at 2.5 THz while the receiver noise bandwidth was 4 GHz.
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Publisher Place of Publication Cambridge, MA, USA Editor Harward University
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 332
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