LOW NOISE MILLIMETER WAVE RECEIVER

IN THE PAST 10 YEARS MUCH PROGRESS HAS BEEN MADE IN THE DEVELOPMENT OF LOW NOISE RECEIVERS WHICH CAN SERVE AS IMAGING MILLIMETER WAVE DEVICES. THE APPLICATION OF QUASI-OPTICAL TECHNIQUES HAS BEEN ONE SOURCE OF HELP TO MILLIMETER WAVE SYSTEMS. DEVELOPMENTS IN SUPERCONDUCTOR-INSULATOR-SUPERCONDUCTOR (SIS) TUNNEL JUNCTIONS AND HIGH ELECTRON MOBILITY TRANSISTOR (HEMT) TECHNOLOGY HAVE ALSO BEGUN TO PRODUCE LOW NOISE MIXERS AND AMPLIFIERS AT MILLIMETER WAVE FREQUENCIES. COOLED MIXERS, USED FOR EVERAL DECADES IN RADIO ASTRONOMY APPLICATIONS, ARE ALSO CANDIDATES FOR IMPROVING SYSTEM NOISE FIGURES. MILLIMETER WAVE TECHNOLOGY PROPOSES TO EVALUATE THE CURRENT STATE OF LOW NOISE TECHNOLOGY AND PRODUCE AN OPTIMUM SYSTEM DESIGN AT 35 AND 95 GHZ.