Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE

Noise properties of a mixer with SIS NbN quasi-particle tunnel junctions

Alexandre Karpov, B. Plathner, K. H. Gundlach, Masahiro Aoyagi, S. Takada

Published Oct 13, 1995• 3 citations

Abstract

We present the noise properties of a mixer with the NbN-MgO-NbN quasiparticle tunnel junctions. Our work is based on experiment in the 120-180 GHz range with the NbN tunnel junctions in the mixer. Mixer printed circuit is totally made of NbN. The mixer operates at 5.4 K temperature unacceptable with Nb junctions. The minimum DSB receiver noise temperature is about 65 K at 162 GHz and approaches the Nb SIS mixer performance in mm band. It has been found that the noise sources in the NbN junctions are comparable to the Nb junctions and that the receiver noise with the NbN SIS mixer may be only few times more than the quantum limit of noise in the frequency range below the gap frequency. Output noise of the SIS mixer has been found constant in a wide frequency band and within an important range of the local oscillator amplitudes.

DOI: 10.1117/12.224232

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