Josephson junction as F-band mixer-multiplier

Properties of a niobium-niobium Josephson superconducting point contact (SPC) used as a mixer-multiplier have been investigated experimentally. Conversion of a microwave signal with frequency f^s= 127 GHz into a signal with the intermediate frequency f^if= 8.6 GHz has been obtained using heterodyne generators with frequencies f^h= 136.68, 45, and 6.8 GHz, so that f^if= nf^{h1,2,3 ....20}- f^swhere n = 1.2, 3.20 are heterodyne harmonics produced in the SPC. Dependences of the conversion efficiency (ηn) on the bias voltage, the heterodyne power and the heterodyne harmonics have been measured. In the case of the second and the twentieth harmonics, the best value of η20/η2was 0.25. This value is essentially higher than that obtained for the usual (conventional) semiconducting mixer. Performed experiments have demonstrated the perspective of utilization of SPC as a mixer-multiplier in millimeter and submillimeter wavebands.