Microwave noise parameter measurements of a high temperature superconducting flux flows transistor

The noise parameters of a high-temperature superconducting (HTS) flux flow transistor made of TlBaCaCuO operating at 77 K and 3-5 GHz were experimentally determined. It is assumed that the dominant noise mechanism of the device, which is based on an array of weak links with a magnetic control line, is due to the statistical nature of flux nucleation and motion in the links. The noise parameters dictate the dependence of the noise figure on the source impedance, and are calculated by measuring source impedances. Sensitivity analysis is used to estimate the accuracy of the measurements. The measurements indicate a minimum noise figure of less than 1 dB at 3 GHz.