关键词：传感器；超导体；电路；探测器；德国；约瑟夫森结；参量放大器；物理学；射频；灵敏度；波导；外电报道；鱿鱼（超导量子干涉器件）
摘 要：The RF directional sensor based on phase-sensitive detection using two sorts of Josephson parametric amplifiers has been analyzed and investigated experimentally. To construct the Josephson parametric amplifier, we use a SQUID (either single-cell SQUID or two-cell SQUID) embedded in a superconducting coplanar waveguide. We operated the circuit at a frequency of several GHz and measured the amplitude response of the SQUID-based Josephson parametric amplifier. Nonlinearity and flux tunability in the reported experiments was limited by relatively large critical current density and therefore small nonlinear inductance of the SQUID. The demonstrated phase sensitivity was 1.2 dB / rad. It appears feasible to improve the sensitivity of developed RF sensor by reducing the critical current of the Josephson junctions.