Millimeter wave mixing in thin‐film YBCO Josephson junctions

Harmonic mixing characteristics were examined in a 94‐GHz millimeter wave region at liquid‐nitrogen temperature (77 K) using thin‐film YBa 2 Cu 3 O 7 ‐ x (YBCO) Josephson junctions created by laser ablation. As a result, a mixing signal (IF output) with a harmonic number (N) of up to 30 was obtained in harmonic mixing using the LO wave as the microwave. The output depended strongly on the power of the LO wave and the Shapiro step spacing induced by the LO wave. It was approximately proportional to N −2 .