| Two-dimensional arrays of Josephson junctions have been shown to emit coherent power at frequencies up to 400 GHz. Because even a single junction may have extremely complex dynamical behavior, an analysis of array oscillators must begin with a detailed investigation of the single junctions which make up an array. In the beginning of this dissertation, the experimental and analytical tools for such an analysis are developed. The operation of two-dimensional Josephson-junction array oscillators is then confirmed for several different array designs.;Junctions in an array are part of a complex spatially-distributed electromagnetic environment, and do not behave the same as when they are isolated. Most theoretical descriptions of Josephson junction array oscillators, however, treat the array as a lumped circuit and ignore the distributed nature of the array. Although the arrays discussed here are smaller than the radiation wavelength (a requirement of the lumped description), these models do not adequately describe many of the experimental results presented in this dissertation. To address these issues, a distributed model is presented.;In this model, the junctions cannot be treated separately from the distributed structure of the array, and the distributed structure cannot be treated separately from the junctions. To test the model, simulations are compared to experiments. Experimental results which are not predicted by lumped models are qualitatively reproduced by numerical simulations based on the distributed model. This agreement shows that the distributed nature of a Josephson-junction array oscillator is an important property which may strongly influence the dynamics of the array.;Since increasing the critical current of junctions in an array increases the theoretical maximum power from the array, high critical-current arrays are investigated. Anomolous behavior is shown to occur when the critical current is increased. This result is also qualitatively reproduced by the distributed model. |
