TY  - CONF
AU  - Vachtomin, Y. B.
AU  - Antipov, S. V.
AU  - Maslennikov, S. N.
AU  - Smirnov, K. V.
AU  - Polyakov, S. L.
AU  - Kaurova, N. S.
AU  - Grishina, E. V.
AU  - Voronov, B. M.
AU  - Gol'tsman, G. N.
PY  - 2004
DA  - 2004//
TI  - Noise temperature measurements of NbN phonon-cooled hot electron bolometer mixer at 2.5 and 3.8 THz
T2  - Proc. 15[super:th] Int. Symp. Space Terahertz Technol.
BT  - Proc. 15[super:th] Int. Symp. Space Terahertz Technol.
SP  - 236
EP  - 241
CY  - Northampton, Massachusetts, USA
KW  - HEB mixer
KW  - NbN
KW  - direct detection effect
AB  - We present the results of noise temperature measurements of NbN phonon-cooled HEB mixers based on a 3.5 nm NbN film deposited on a high-resistivity Si substrate with a 200 nm - thick MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for the 3 µm x 0.2 µm active area devices. The best uncorrected receiver noise temperatures found for these frequencies are 1300 K and 3100 K, respectively. A water vapour discharge laser was used as the LO source. We also present the results of direct detection contribution to the measured Y-factor and of a possible error of noise temperature calculation. This error was more than 8% for the mixer with in-plane dimensions of 2.4 x 0.16 µm 2 at the optimal noise temperature point. The use of a mesh filter enabled us to avoid the effect of direct detection and decrease optical losses by 0.5 dB. The paper is concluded by the investigation results of the mixer polarization response. It was shown that the polarization can differ from the circular one at 3.8 THz by more than 2 dB.
UR  - https://www.nrao.edu/meetings/isstt/2004.shtml
N1  - exported from refbase (https://db.rplab.ru/refbase/show.php?record=344), last updated on Tue, 18 May 2021 12:50:32 -0500
ID  - Vachtomin_etal2004
ER  -