SUBHARMONICALLY PUMPED BSSCO MICROWAVE MIXERS OPERATED AT KA BAND AND77 K

Heterodyne mixing of two microwave signals has been observed for the f irst time at 77 K in Bi-(Pb)-Sr-Ca-Cu-O thin-film mixers patterned on MgO substrates. A number of different device designs were tested (all at 77 K) with an RF signal of 26 GHz and 36 GHz. In each case the mixe rs were subharmonically pumped with a 12 GHz local oscillator. The res ulting IF signals observed were in the 1 MHz-2 GHz range with signal t o noise typically 60 dB. The maximum IF frequency observed was 8 GHz. Investigation of IF output power as a function of applied RF power rev ealed a linear relationship whereas IF power as a function of local os cillator power exhibited a maximum at a local oscillator power of -10 dBm. Down-conversion of a 26 GHz carrier modulated with a 1.6 MHz test signal was also achieved.