High frequency detector response from an array of HTSC bicrystal Josephson junctions

YBaCuO Josephson junction arrays, fabricated on MgO bicrystal substrates were studied in wide frequency range at 7-26 GHz, 45-120 GHz, and at submillimeter 470-510 GHz waves. Subharmonic fractional Shapiro steps have been observed with amplitudes increasing with frequency of applied microwaves. Mm and submm wave harmonic and subharmonic selective detector response signals were registered when dc magnetic field was applied.