A simple method of RF-SQUID analysis and its application to a SQUID with a separate driving coil

A simple method is developed for analysis of rf SQUIDs operating in the hysteretic mode, for arbitrary values of rf detuning and plateau number. For plateaus with large numbers, the reactive component of the interferometer flux is shown to be essential. The results of theoretical analysis are confirmed by experiments with a 10 MHz point-contact SQUID. The new method is applied to studies of a SQUID with a separate coil for driving flux. The response curve slope in such SQUID can be somewhat larger than that in the conventional rf SQUID. The balanced SQUID circuits are also discussed.