ISSTT Proceedings

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Improved Characteristics of NbN HEB Mixers Integrated with Log-Periodic Antennas

Authors:
E. Gerecht, C. F. Musante, H. Jian, Y. Zhuang, K. S. Yngvesson, J. Dickinson, T. Goyette, J. Waldman, P. A. Yagoubov, G. N. Gol'tsman, B. M. Voronov, E. M. Gershenzon
Abstract:
Hot Electron Bolometric (HEB) mixers have recently demonstrated the lowest receiver noise temperatures ever measured in the THz frequency region. HEB receivers have become the most promising approach for applications such as high-resolution heterodyne spectral measurements of astronomical objects from airborne or space-based platforms at frequencies above 1 THz. At most frequencies the lowest noise temperatures attained so far have used NbN Phonon-cooled HEB (PHEB) mixers. We have developed NbN PHEB devices and have improved their characteristics very substantially since our paper at the Ninth STT Symposium. We report total DSB receiver noise temperatures of 485 K at 620 GHz (440 K when the device was cooled to 3 K), 1,000 K at 1.56 THz, and 2,200 K at 2.24 THz. NbN HEB mixers have been shown to have sufficient bandwidths for the anticipated applications such as future receiver frontends for THz astronomical observation from space. We have measured a conversion gain bandwidth of 3 GHz at 620 GHz for one of our devices and calculated the receiver noise bandwidth to be 6.5 GHz with a sufficiently wideband IF amplifier. The lowest LO power required is 500 nW which makes NbN PHEB mixers suitable for use with future solid state tunable THz sources. However, the LO power is not at such a low level that its operating point is affected by input thermal noise power. This paper describes the development of our NbN PHEB mixers and discusses device fabrication and optical coupling issues as well as our measurement setup and results.
Categories:
HEB Mixers
Year:
1999
Session:
5
Full-text:
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Page Number(s):
200-207