Measurement of frequency above 100 GHz with high-Tc Josephson junction array

YBaCuO series arrays composed of 23 bicrystal grain boundary Josephson junctions incorporated into 2-arm logarithmic spiral antenna and coupled to a broadband quasi-optic lens system were applied for determination of frequencies above 100 GHz by comparing the DC voltages aroused over the array under MM-wave irradiation, with a solid-state reference cell. Full phase-lock of all junctions under some 0.1 mW incident power at frequency 146 GHz (presence of 23-fold Shapiro step) was obtained for a YSZ-substrate array at temperatures up to 68 K. We verified the precision of the proposed instrument by measuring time frequency drifts for both the 100 GHz Gunn diode oscillator and the 150 GHz backward-wave oscillator.