Quasi-optical slot antenna SIS mixers
- Creators
-
Zmuidzinas, Jonas
- LeDuc, H. G.
Abstract
A quasi-optical SIS mixer designed for efficient radiation coupling is described. The mixer uses a twin-slot antenna which has the advantages of a good beam pattern and a low impedance. The radiation and impedance characteristics of the antenna were obtained from a moment-matched calculation. Tapered superconducting microstrip transmission lines are used to carry the radiation from the slot antennas to the tunnel junction. The effective impedance seen by the tunnel junction is quite low, about 4 Ω, which allows micron-size junctions to be used at 500 GHz. The mixers have been fabricated using Nb/Al-oxide/Nb tunnel junctions and a receiver noise temperature of 420 K (DSB) was measured at 490 GHz, which is the best yet obtained for a quasi-optical mixer at this frequency. The comparatively large junction area increases the mixer saturation power and allows strong suppression of noise from the Josephson effect by the application of a magnetic field of modest strength.
Additional Information
© Copyright 1992 IEEE. Reprinted with permission. Manuscript received October 1, 1991; revised January 29, 1992. This work was supported in part by NASA grant NAGW-107, NASA/JPL, an NSF Presidential Young Investigator grant to J. Zmuidzinas, and NSF grant DPP88-18384 (to University of Illinois). We wish to thank T. Büttgenbach and J. Stern for helpful discussions, J. Carlstrom for assistance with the measurements, and R. Pöpel for communicating the results of his nonlocal calculations of the surface impedance of Nb. J.Z. is indebted to K.Y. Lo and T.G. Phillips for advice and encouragement, and to F. Sharifi and D. Van Harlingen for his introduction to superconducting device fabrication.Files
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Additional details
- Eprint ID
- 10409
- Resolver ID
- CaltechAUTHORS:ZMUieeetmtt92
- Created
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2008-05-02Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field