DEVELOPMENT OF A LOW LOSS PLANAR HTSC MILLIMETER WAVE MIXER

MANY INFRARED AND ELECTRO-OPTICAL IMAGING SYSTEMS ARE CONFOUNDED BY FOG AND DUST. MILLIMETER EAVE IMAGING SYSTEMS WOULD NOT BE AFFECTED BY THESE BATTLEFIELD OBSCURANTS. HOWEVER, THE LIQUID HELIUM COOLING REQUIREMENT OF TODAYS HIGH PERFORMANCE LOW NOISE MIXERS IS BLOCKING THE DEPLOYMENT OF ADVANCED MILLIMETER WAVE COMMUNICATIONS AND IMAGING SYSTEMS. IN PRINCIPAL, JOSEPHSON MIXERS FABRICATED WITH THE NEW HIGH T(C) SUPERCONDUCTORS (HTSC) COULD ALEVIATE THIS CONSTRAINT. HOWEVER, SEVERAL PROCESSING PROBLEMS NEED TO BE OVERCOME BEFORE THE MANUFACTURE OF MILLIMETER WAVE MIXERS CAN BE ACHIEVED. THE OBJECTIVE OF THE PHASE I PROGRAM IS TO DETERMINE THE FEASIBILITY OF PRODUCING HTSC MIXERS WITH JOSEPHSON JUNCTIONS MADE FROM THE GRAIN BOUNDARIES TRANSVERSING 10 X 5 MICRON(2) MICROBRIDGES. FOUR WAFERS CONTAINING EIGHT DEVICES EACH WILL BE PROCESSED. THE PROPERTIES OF THE FILMS WILL BE CORRELATED TO THE I-V CURVES OF HTSC MICROBRIDGES. THESE RESULTS WILL ESTABLISH PERFORMANCE VARIATIONS BETWEEN DEVICES AND OVERALL DEVICE YIELD. PHASE II WILL FOCUS ON THE PROCESSING, PACKAGING AND TESTING OF THE HTSC MIXERS AT 100 GHZ. THE MAJOR ADVANTAGE OF THIS APPROACH IS THAT RATHER THAN REQUIRING PERFECT THIN FILMS, IT UTILIZES FLAWS PRESENT IN THE CURRENTLY AVAILABLE MATERIAL TO PLACE A WORKING PROTOTYPE INTO THE FIELD.