Power gain of a SQUID amplifier

Publisher Website
Google Scholar
Abstract
The power gain of a dc superconducting quantum interference device (SQUID) amplifier, with tuned input and output circuits, is computed as a function of the current and magnetic biases. A gain of 20300 is found at 1.5 GHz and 3470 at 3.0 GHz, implying a frequency dependence to the gain of approximately ω−2. The gain, as derived from the resistively shunted junction model, is compared with the gain of a simplified model based on the dc magnetic response Vφ. This comparison shows that the Vφ description of the SQUID can lead to large errors.