Development of RF Sensor Based on Two Cell SQUID

In this project, we proposed to develop and investigate a sensitive microwave sensor based on a two-cell SQUID by imitating the operational principle of the fly's ears. The fly ormia shows astonishing localization ability with its tiny hearing organ. In this report, we show first measurement results based on several available Josephson junction (JJ) circuits. We investigated the current-voltage characteristics as a function of external magnetic field. We have also developed a new experimental setup for applying microwave signals with controllable phase shift and observed the response of the SQUID circuits to small variations of the phase and/or amplitude of two microwave signals coupled off-chip. We find that the dc voltage of the studied two-cell SQUID varied by 0.02 μV under the change of the phase difference of the microwave radiation signal by 1°. Furthermore, we designed new specially tailored SQUID circuits dedicated for measurements of the microwave phase difference between two incoming signals. The designed circuits have been submitted for fabrication at Hypres Inc.