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Author Nagatsuma, T.; Hirata, A.; Sato, Y.; Yamaguchi, R.; Takahashi, H.; Kosugi, T.; Tokumitsu, M.; Sugahara, H.; Furuta, T.; Ito, H.
Title Sub-Terahertz Wireless Communications Technologies Type Conference Article
Year 2005 Publication Proc. 18th International Conference on Applied Electromagnetics and Communications (ICECom 2005) Abbreviated Journal
Volume Issue Pages 1-4
Keywords subterahartz terahertz THz communications
Abstract (up) This paper presents a 10-Gb/s wireless link system that uses a 120-GHz-band sub-terahertz electro-magnetic waves. In the transmitter, photonic techniques are used for generation, modulation, and emission of the sub-THz signals, while the receiver is composed of all-electronic devices using InP-HEMTs.
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Notes Approved no
Call Number Serial 593
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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 (up) 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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Corporate Author Thesis
Publisher Place of Publication Göteborg, Sweden Editor
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Notes Approved no
Call Number Serial 360
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Author Finkel, M. I.; Maslennikov, S. N.; Gol'tsman, G. N.
Title Terahertz heterodyne receivers based on superconductive hot-electron bolometer mixers Type Journal Article
Year 2005 Publication Radiophys. Quant. Electron. Abbreviated Journal Radiophys. Quant. Electron.
Volume 48 Issue 10-11 Pages 859-864
Keywords HEB, applications
Abstract (up) We consider recent results in development of hot-electron bolometer mixers. Special attention is paid to optimization of the contacts between the antenna and the active area of a superconducting film. An important result in the study of the parasitic effect of direct detection is obtained during the measurement of the noise temperatures by the hot/cold load method. The latest results of studies of the waveguide hot-electron bolometer mixers and their successful practical applications are considered. Progress in development of high-frequency (over 1.3 THz) heterodyne receivers for several important international projects is discussed and new submillimeter radio astronomy projects ESPRIT and SAFIR are described.
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ISSN 0033-8443 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 381
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Author Baselmans, J. J. A.; Hajenius, M.; Gao, J. R.; Baryshev, A.; Kooi, J.; Klapwijk, T. M.; Voronov, B.; de Korte, P.; Gol'tsman, G.
Title NbN hot electron bolometer mixers: sensitivity, LO power, direct detection and stability Type Journal Article
Year 2005 Publication IEEE Trans. Appl. Supercond. Abbreviated Journal IEEE Trans. Appl. Supercond.
Volume 15 Issue 2 Pages 484-489
Keywords HEB mixers, direct detection effect, stability, Allan variance
Abstract (up) We demonstrate that the performance of NbN lattice cooled hot electron bolometer mixers depends strongly on the interface quality between the bolometer and the contact structure. Both the receiver noise temperature and the gain bandwidth can be improved by a factor of 2 by cleaning the interface and adding an additional superconducting interlayer to the contact pad. Using this we obtain a double sideband receiver noise temperature of 950 K at 2.5 THz and 4.3 K, using a 0.4/spl times/4 /spl mu/m HEB mixer with a spiral antenna. At the same bias point, we obtain an IF gain bandwidth of 6 GHz. To comply with current demands on THz mixers for use in space based receivers we reduce the device size to 0.15/spl times/1 /spl mu/m and use a twin slot antenna. We report measurements of the noise temperature, LO power requirement, stability and the direct detection effect, using a mixer with a 1.6 THz twin slot antenna and a 1.462 THz solid state LO source with calibrated output power.
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1051-8223 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number Serial 546
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Author Yang, Z. Q.; Hajenius, M.; Baselmans, J. J. A.; Gao, J.R.; Klapwijk, T. M.; Voronov, B.; Gol’tsman, G.
Title Improved sensitivity of NbN hot electron bolometer mixers by vacuum baking Type Conference Article
Year 2005 Publication Proc. 16th Int. Symp. Space Terahertz Technol. Abbreviated Journal Proc. 16th Int. Symp. Space Terahertz Technol.
Volume Issue Pages 222-225
Keywords NbN HEB mixer
Abstract (up) We find that the sensitivity of heterodyne receivers based on superconducting hot-electron bolometer (HEB) in- creases by 25 − 30% after baking at 85 o C and in a high vacuum. The devices studied are twin-slot antenna coupled HEB mixers with a small NbN bridge of 1×0.15 μm 2 . The mixer noise temperature, gain, and resistance versus temperature curve of a HEB before and after baking are compared and analyzed. We show that baking reduces the intrinsic noise of the mixer by 37 % and makes the superconducting transition of the bridge and the contacts sharper. We argue that the reduction of the noise is due to the improvement of the transparency of the contact/film interface. The lowest receiver noise temperature of 700 K is measured at a local oscillator frequency of 1.63 THz and a bath temperature of 4.3 K.
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Notes Approved no
Call Number Serial 1471
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