Dynamic range of frequency-selective response of high-T-c Josephson detector to millimeter-wave radiation

We have studied a voltage dependence of the response DeltaI(V) of high-T-c Josephson detector to millimeter-wave radiation as a function of power of i ncident radiation. YBa2Cu3O7-x grain-boundary junctions with the resistance s R-x = 0.5-1.5 Ohm and the Wt-product In the range 0.16-0.25 mV at 80 It h ave been fabricated for this study. Gunn oscillator with the frequency f= 8 6 GHz and a set of calibrated attenuators with total attenuation of 80 dB h ave been used for the measurements. The dynamic range, i.e. the range of po wer of electromagnetic radiation at which the response of the detector is d irectly proportional to radiation power, was found to be around 40 dB above the noise-equivalent power for frequency-selective response V voltages V n ear hf/2e and > 45 dB for the broadband response at low voltages.