Self-Emission From Arrays of Overdamped Josephson Junctions

Two self-emission peaks around 75 GHz and 80 GHz were observed from a series array of 7500 overdamped Josephson junctions. They originated from two corresponding resonant modes of the junction substrate served as a dielectric resonator antenna. With decreasing the operation temperature, the emission power was improved due to the increase in the critical current and the suppression of the Joule heating. Based on this method, it is promising to apply Josephson junctions as compact oscillators in terahertz frequency range.