Superconducting quantum interference device amplifiers with over 27 GHz of gain-bandwidth product operated in the 4-8 GHz frequency range

We describe the performance of amplifiers in the 4-8 GHz range using direct current (dc) superconducting quantum interference devices (SQUIDs) in a lumped element configuration. We have used external impedance transformers to couple power into and out of the dc SQUIDs. By choosing appropriate values for coupling capacitors, resonator lengths and output component values, we have demonstrated useful gains in several frequency ranges with different bandwidths, showing over 27 GHz of power gain-bandwidth product. In this work, we describe our design for the 4-8 GHz range and present data demonstrating gain, bandwidth, dynamic range, and drift characteristics. [DOI: 10.1063/1.3220061]