Microwave losses of interferometers with many Josephson junctions versus DC magnetic field

The average microwave losses of interferometers with two and four strongly damped Josephson junctions biased by a microwave current source at 10 GHz much below the plasma frequency have been simulated as a function of an external magnetic field. Microwave losses appear periodically within distinct ranges of the magnetic field, with microwave amplitudes below and above threshold currents. The main period corresponds to one flux quantum in every interferometer loop. The absorption rate increases with the microwave amplitude in qualitative agreement with measurements.<>