Microwave Harmonic Generation from Josephson Junctions

An easily fabricated bulk form of Josephson junction has been used as a harmonic generator. Harmonically generated power emitted by these nonresonant junctions has been directly detected at about 12 Gc/sec, corresponding to the second or third harmonic of the input frequency. The harmonic output is sensitive to the bias point in the V-I characteristic and to the input power level as expected from Josephson's equations. The coupling to waveguide of the radiation emitted by the nonresonant junctions used in these experiments is superior to that achieved in earlier work using self-resonant junctions as microwave generators.