... LO frequencies were 1/2, 1/3 and 1/8 of signal frequency 75 GHz. ... But single junction SIS mixer has 30 dB input signal power range only [ll and it may decrease at high frequencies more than 200 GHz due to Josephson and 1 "switching" noise rise [2 e Our experiments show that subhurmonically pumped SIS mixer may have improved saturation power and reduced noise at high frequencies in some operation modes. ... 269 Fig.2 Quantum for LO and signal frequencies SIS operating mode. ...