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Author Kroug, M.; Cherednichenko, S.; Choumas, M.; Merkel, H.; Kollberg, E.; Hübers, H.-W.; Richter, H.; Loudkov, D.; Voronov, B.; Gol'Tsman, G. url  openurl
  Title HEB quasi-optical heterodyne receiver for THz frequencies Type Conference Article
  Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal  
  Volume Issue Pages (up) 244-252  
  Keywords HEB mixer, NbN, MgO, conversion gain bandwidth, noise temperature  
  Abstract  
  Address  
  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  
  ISSN ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number Serial 319  
Permanent link to this record
 

 
Author Ekström, H.; Karasik, B.; Kollberg, E.; Gol'tsman, G.; Gershenzon, E. url  openurl
  Title 350 GHz NbN hot electron bolometer mixer Type Conference Article
  Year 1995 Publication Proc. 6th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 6th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages (up) 269-283  
  Keywords NbN HEB mixers  
  Abstract Superconducting NbN hot-electron bolometer (HEB) mixer devices have been fabricated and measured at 350 GHz. The HEB is integrated with a double dipole antenna on an extended crystalline quartz hyper hemispherical substrate lens. Heterodyne measurement gave a -3 dB bandwidth, mainly determined by the electron- phonon interaction time, of about 680 and 1000 MHz for two different films with Tc = 8.5 and 11 K respectively. The measured DSB receiver noise temperature is around 3000 K at 800 MHz IF frequency. The main contribution to the output noise from the device is due to electron temperature fluctuations with the equivalent output noise temperature TFL-100 K. TH, has the same frequency dependence as the IF response. The contribution from Johnson noise is of the order of T. The RF coupling loss is estimated to be = 6 dB. The film with lower Tc, had an estimated intrinsic low-frequency conversion loss = 7 dB, while the other film had a conversion loss as high as 14 dB. The difference in intrinsic conversion loss is explained by less uniform absorption of radiation. Measurements of the small signal impedance shows a transition of the output impedance from the DC differential resistance Rd=dV/dI in the low frequency limit to the DC resistance R 0 =Uoff 0 in the bias point for frequencies above 3 GHz. We judge that the optimum shape of the IV-characteristic is more easily obtained at THz frequencies where the main restriction in performance should come from problems with the RF coupling.  
  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 1628  
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Author Cherednichenko, S.; Kroug, M.; Merkel, H.; Kollberg, E.; Loudkov, D.; Smirnov, K.; Voronov, B.; Gol'tsman, G.; Gershenzon, E. url  openurl
  Title Local oscillator power requirement and saturation effects in NbN HEB mixers Type Conference Article
  Year 2001 Publication Proc. 12th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 12th Int. Symp. Space Terahertz Technol.  
  Volume Issue Pages (up) 273-285  
  Keywords NbN HEB mixers, LO power, local oscillator power, saturation effect, dynamic range  
  Abstract The local oscillator power required for NbN hot-electron bolometric mixers (P LO ) was investigated with respect to mixer size, critical temperature and ambient temperature. P LO can be decreased by a factor of 10 as the mixer size decreases from 4×0.4 µm 2 to 0.6×0.13 µm 2 . For the smallest volume mixer the optimal local oscillator power was found to be 15 nW. We found that for such mixer no signal compression was observed up to an input signal of 2 nW which corresponds to an equivalent input load of 20,000 K. For a constant mixer volume, reduction of T c can decrease optimal local oscillator power at least by a factor of 2 without a deterioration of the receiver noise temperature. Bath temperature was found to have minor effect on the receiver characteristics.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication San Diego, CA, USA Editor Jet Propulsion Laboratory, California Inst.it.u.t.e of Technology  
  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 318  
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Author Dzardanov, A.; Ekstrom, H.; Gershenzon, E.; Gol'tsman, G.; Jacobsson, S.; Karasik, B.; Kollberg, E.; Okunev, O.; Voronov, B.; Yngvesson, S. doi  openurl
  Title Hot-electron superconducting mixers for 20-500 GHz operation Type Conference Article
  Year 1994 Publication Proc. Int. Conf. on Millimeter and Submillimeter Waves and Appl. Abbreviated Journal  
  Volume 2250 Issue 4D Pages (up) 276-278  
  Keywords  
  Abstract Bolometdcmucers based on Nb and NbN superconducting thin films in the resistive state have been prepared for 20, 100 GHz and 350-500 GHz operation. The mixing mechanism is presumably of electron heating origin. Our measurements indicate that a conversion loss of about 6-8 dB can rather easily be achieved, and that the noise is reasonably low. The requirements on the operation mode and on the film parameters in order to obtain small conversion losses or even gain are discussed. For NbN films the availability of nearly 1 GHz IF bandwidth is experimentally demonstrated. NbN hot-electron mucers combined with slot-line tapered antenna on Si membrane or with double-dipole antenna on SiO^ substrate have been fabricated. The devices we study are considered to be very promising for use in heterodyne receivers from microwaves to terahertz frequencies.  
  Address  
  Corporate Author Thesis  
  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  
  Notes Approved no  
  Call Number RPLAB @ phisix @ Serial 981  
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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. url  doi
openurl 
  Title Noise temperature and absorbed LO power measurement methods for NbN phonon-cooled hot electron bolometric mixers at terahertz frequencies Type Conference Article
  Year 1998 Publication Proc. 28th European Microwave Conf. Abbreviated Journal Proc. 28th European Microwave Conf.  
  Volume 1 Issue Pages (up) 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.  
  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 28th European Microwave Conference  
  Notes Approved no  
  Call Number Serial 1580  
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