AlN Barrier SIS Junctions in Submm Heterodyne Receivers: Operational Aspects

J. Bout, A. Baryshev, J. Barkhof, F. P. Mena, R. Hesper, B. Jackson, W. Wild, C. F. J. Lodewijk, D. Ludkov, T. Zijlstra, E. van Zeijl, T. M. Klapwijk



The Atacama Large Millimeter Interferometer (ALMA) [1] site is an observatory which consists of more than fifty 12 meter diameter sub-mm telescopes, located at an altitude of 5000 m in the Atacama desert in Chile. It covers the 30-950 GHz frequency range which is divided into ten bands following the atmospheric transmission windows. ALMA front-ends will be using superconductor-Insulator-Superconductor (SIS) heterodyne mixers as the key sensitive elements for all of its high frequency bands. The ALMA band 9 receiver which covers 600-720 GHz is being developed in the Netherlands. The first eight receivers have already been built based on AlOx barrier SIS junctions mixers. These mixers have excellent noise temperature but show limited RF and IF bandwidth. Using new AlN barrier higher current density SIS junctions, it is possible to improve on the RF and IF bandwidth of SIS mixers thus making this technology significantly more attractive for the use in large series of SIS receivers. Currently, a good sensitivity and band coverage has already been achieved for AlN mixers. However, performance of AlN mixers at higher frequencies depends highly on Josephson noise suppression and is only optimal if a precise magnetic field is applied on the barrier. Present routines
for Josephson noise suppression in AlOx barrier mixers were not sufficient. In this paper these routines will be discussed in detail and its adaptation to AlN barrier mix er operation will be reported.
Originele taal-2English
TitelProceedings of the Ninteenth International Symposium on Space Terahertz Technology, held April 28-30, 2008, in Groningen
RedacteurenWolfgang Wild
Aantal pagina's1
StatusPublished - 1-apr.-2008
Evenement19th International Symposium on Space Terahertz Technology 2008 - Groningen, Netherlands
Duur: 28-apr.-200830-apr.-2008


Conference19th International Symposium on Space Terahertz Technology 2008


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