NASA Jet Propulsion Lab Collaboration

Cryogenic Low-Noise Amplifiers for Large Arrays. Very Low Noise Amplifiers (LNAs) are being developed for use in various large array projects including the Allen Telescope Array. Low noise is desirable in large arrays because an increase in the receiver noise directly translates to a need for more antennas to achieve the same performance. Because these arrays require hundreds of receivers, it is important to have inexpensive and reliable LNAs. Information on the Allen Telescope can be found at http://www.seti.org . Click on "Allen Telescope" in the menu.

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Low-Noise AmplifiersI

Wideband antennas commonly have a differential input necessitating a passive balun to connect to a standard single-ended LNA. These passive baluns are often phusically large and lossy. Therefore, an LNA has been developed with a differential input to eliminate the need for a passive balun. These "active baluns" achieve the same noise performance as a single-end common source stage. The chip on the left is 2mm x 1.6 mm and has a noise temperature of better than 8K (0.12 dB noise figure) at a physical temperature of 15K. It is shown mounted with an input matching circuit and biasing circuitry. The photo on the right is the amplifier module holding the chip.

References:

Cryogenic, Wide-Band, Ultra-low noise IF Amplifiers operating at Ultra-Low DC Power, N. Wadefalk, A. Mellberg, I. Angelov, M. Barsky, S. Bui, E. Choumas, R. Grundbacher, E. Kollberg,R. Lai, N. Rorsman, P. Starski, J. Stenarson, D. Streit, and H. Zirath, IEEE, Trans. Microwave Theory and Techniques, Vol. 51, No. 6, pp. 1705-1711, June 2003.

Cryogenic 1.5-4.5 GHz Ultra-Low Noise Amplifier , Niklas Wadefalk*, Anders Mellberg, Iltcho Angelov, Emmanuil Choumas**, Erik Kollberg, Niklas Rorsman, Piotr Starski, Jörgen Stenarson, and Herbert Zirath *California Institute of Technology, Electrical Engineering Dept, 1200 E.California Boulevard, Pasadena, CA 91125 Chalmers University of Technology, Dept of Microelectronics, SE-412 96 Göteborg, Sweden **Unaxis Trading AG, Truebbach, Switzerland


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updated November 29, 2005