ISSTT Proceedings

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Terahertz NbN/AlN/NbN Mixers with Al/SiO/NbN Microstrip Tuning Circuits

Authors:
Yoshinori Uzawa, Zhen Wang, Akira Kawakami
Abstract:
We have developed a low-noise quasi-optical NbN/A1N/NbN SIS mixer that operates at terahertz frequencies. The mixer uses a MgO hyperhemispherical lens with an antireflection cap, a single-crystal NbN log-periodic antenna, and two-junction tuning circuits which employ Al/SiO/NbN microstriplines. The NbN/A1N/NbN junction size was about 0.9 in diameter, and the current density was about 45 kA/cm². The frequency-dependence of the receiver noise temperature was investigated by using an optically pumped far-infrared laser and a backward-wave oscillator as a local oscillator at several frequencies from 670 GHz to 1082 GHz. The experimental results showed that the center frequency was around 800 GHz, and the receiver noise temperature measured by the standard Y-factor method was 457 K(DSB) at 783 GHz including a 9 µm-thick Mylar beam splitter loss and other optical losses at the physical bath temperature of 4.2 K. This is the first SIS mixer based on NbN with lownoise performance (12hv/KB) above the gap frequency of Nb.
Categories:
Devices, Receivers
Year:
1998
Session:
7
Full-text:
Download a PDF of this paper.
Page Number(s):
273-281