New Type of Superconducting Low Noise Amplifier

Period of Performance: 09/14/1998 - 03/13/1999


Phase 1 SBIR

Recipient Firm

Quasar, Inc.
Principal Investigator


Approximately 12 months ago a new amplification effect of over 30 dB was obtained in, DC Superconducting Quantum Interference Device (SQUID). The amplification is based on measuring the circulating current in the SQUID, instead of the induced voltage, which is the present practice. To achieve the high gain the SQUID must be biased into a regime in which in switches between internal flux states under the effect of thermal noise. A new high frequency amplifier is proposed that exploits this enhanced amplification effect. Based on the observed behavior of the switching state in the SQUID and the known characteristics of DC SQUIDs, a gain > 30 dB over a bandwidth potentially exceeding 50 GHz at a noise temperature of order 1 K may be possible for an optimized device. This performance exceeds that achieved in semiconductor technology for all three parameters. In Phase I we will draw up a mathematical model for the complete amplifier system including input coupling and output post amplification. Numerical simulations will be performed to predict the amplifier performance as a function of frequency. We will consider fabrication issues for implementation in low Tc and high Tc technology. The commercial potential for the amplifier will be assessed by considering a specific communications or instrumentation subsystem as a case study.