2008/06/17 by Lafe Spietz, Kent Irwin, Jose Aumentado +1 · 35 citations
Physics and Astronomy · #Amplifier #Electrical impedance #FET amplifier #Microwave #Noise (video) #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Resonator #Squid #Superconducting and THz Device Technology #Superconductivity #Transformer #Transistor #cond-mat.supr-con
paper · pdf · doi:10.1063/1.2970967
published in Applied Physics Letters 93(8) (American Institute of Physics)
arxiv created 2008/06/17 · openalex publication_date 2008/08/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Due to their superior noise performance, superconducting quantum interference devices (SQUIDs) are an attractive alternative to high electron mobility transistors for constructing ultra-low-noise microwave amplifiers for cryogenic use. We describe the use of a lumped element SQUID inductively coupled to a quarter wave resonator. The resonator acts as an impedance transformer and also makes it possible to accurately measure the input impedance and intrinsic microwave characteristics of the SQUID. We present a model for input impedance and gain, compare it to the measured scattering parameters, and describe how to use the model for the systematic design of low-noise microwave amplifiers with a wide range of performance characteristics.