Superconducting microstrip amplifiers with sub-Kelvin noise temperature near 4 GHz

M. P. DeFeo; B. L. T. Plourde

doi:10.1063/1.4742164

Superconducting microstrip amplifiers with sub-Kelvin noise temperature near 4 GHz

Superconductivity 2015-06-05 v2 Instrumentation and Detectors

Authors: M. P. DeFeo , B. L. T. Plourde

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Abstract

We present measurements of an amplifier operating at 3.8 GHz with 150 MHz of bandwidth based on the microstrip input-coil resonance of a dc superconducting quantum interference device (SQUID) with submicron Josephson junctions. The noise temperature is measured using two methods: comparing the signal-to-noise ratio of the system with and without the SQUID in the amplifier chain, and using a modified Y-factor technique where calibrated narrowband noise is mixed up to the SQUID amplifier operating frequency. With the SQUID cooled to 0.35 K we observe a minimum system noise temperature of 0.55 $\pm~0.13$ K, dominated by the contribution from the SQUID amplifier.

Keywords

superconducting microstrip amplifier noise temperature dc SQUID Josephson junctions microstrip input-coil resonance Y-factor technique

Cite

@article{arxiv.1206.2235,
  title  = {Superconducting microstrip amplifiers with sub-Kelvin noise temperature near 4 GHz},
  author = {M. P. DeFeo and B. L. T. Plourde},
  journal= {arXiv preprint arXiv:1206.2235},
  year   = {2015}
}

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