Oscillation spectral linewidth for some phase-locked Josephson-junction arrays

High effective autoregressive method has been applied to the calculation of the oscillation line width for the promising phase-locked Josephson-juncti on arrays. It has been found, that the oscillation linewidth decreases with the number N of Josephson junctions propartionally to N for one-dimensiona l arrays or even more fast for two-dimensional arrays until number N exceed s the coupling radius. It has been shown that in the case of parallel array inserted into superconducting microstrip line, the phase-locked oscillatio n state in-phase could be provided by the strong interaction between Joseph son junctions and electromagnetic standing wave regardless to applied magne tic field. The necessary amplitude of the standing ware is easy attained at McCumber parameter value beta>l, when the high-frequency Josephson-junctio n impedance is small in comparison with the strip-line wave impedance. An e xtra reduction in the linewidth caused by electromagnetic standing nave imp act has also been studied. The results are discussed from viewpoint of the possible applications of the structures as submillimeter wave generators.