Arrays of Josephson junctions coupled by distributed circuits

Both the linewidth reduction and the gain in output power have been analyze d for Josephson-junction arrays with distributed coupling circuits. Differe nt ways of Josephson junction connection to the distributed circuits, as we ll as both the nonlinear interaction effect and the crucial role of high fr equency losses have been studied. It has been found that the contradictory requirements to the junctions as nonlinear active elements on (i) low wave reflection and (ii) high total power produced can be fulfilled by an increa se in number of Josephson junctions with a proper impedance value, The firs t condition is necessary to provide the most reduction in the linewidth, an d the second one is needed to compensate for the power output, An array of the biased in parallel bi-crystal Josephson HTSC junctions coupled by micro strip circuit has been fabricated and preliminary tested.