Theoretical Simulation of the Mixing Performance of Distributed Superconducting Tunnel Junction Arrays at 1.2 THz

Sheng-Cai SHI
Wen-Lei SHAN
Jing LI

Publication
IEICE TRANSACTIONS on Electronics   Vol.E90-C    No.3    pp.556-565
Publication Date: 2007/03/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e90-c.3.556
Print ISSN: 0916-8516
Type of Manuscript: Special Section INVITED PAPER (Special Section on Innovative Superconducting Devices and Their Applications)
Category: 
Keyword: 
SIS,  Nb,  NbN,  NbTiN,  distributed junction,  

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Summary: 
In this paper we focus on the numerical simulation of the mixing behaviors of distributed superconducting junction arrays at 1.2 THz. A novel type of superconducting tunnel junctions, i.e., NbN/AlN/Nb, which have a relatively high gap voltage (4.3 mV) and can reach a critical current density as high as several tens of kA/cm2, are proposed for this characterization along with conventional Nb/AlOx/Nb junctions. The former is incorporated with a NbN/SiO2/Al tuning circuit, and the latter with a Nb/SiO2/Al and a NbTiN/SiO2/Al tuning circuits. The noise performance, local-oscillator power requirement, IF bandwidth, and optimum embedding impedance are thoroughly characterized for the two types of distributed superconducting junction arrays.