During this first reporting period evaluated the performance of two different microwave directional sensors based on two-cell SQUIDs. Two SQUID circuits with different values of McCumber parameter Beta c have been tested. Observed that best results can be obtained when the McCumber parameter Beta c aprox. to 1. Found that the dc voltage of the proposed two-cell SQUID circuit can vary by 1.4 microV when the incoming angle theta varies 1 deg, which is a factor of 70 improvement to our previously obtained result. Also performed preliminary study of the basic properties of such parametric amplifier and its response to the phase difference between the two microwave signals. The further goal of this work would be to replace the single cell SQUID in the resonator by two cell SQUID and operate it by using two phase-shifted microwave pump signals. The transmission through the resonator measured at half the pump frequency should then be sensitively dependent on the phase shift between the two pumps.
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