ULTRA-HIGH SENSITIVITY INTEGRATED HYDROPHONE SENSOR: USING LOW-COST SILICON MICROMACHINED ELEMENTS

HORIZON TECHNOLOGY GROUP, INC. AND NANOSTRUCTURES, INC ("HTG/N") PROPOSE TO MICROMACHINE AND TEST LOW-COST CAPACLTIVE HYDROPHONE SENSORSFROM SINGLE-CRYSTAL SILICON. THESE SENSORS, TOGETHER WITH A PRE-AMP, A/D CONVERTER, AND SERIAL INTERFACE, CAN BE INTEGRATED INTO A MINIATURE LOW-POWER PACKAGE. A CONCEPTUAL DESIGN WILL BE MADE FOR A WATERPROOF PACKAGE AND SIMPLE LIGHT-WEIGHT ELECTRICAL OR FIBER-OPTIC CABLING, FOR LARGE ACOUSTIC ARRAYS. THE UNIQUE CONSTRUCTION OF THE CAPACITIVE SENSOR ALLOWS IT TO BE FLUID FILLED TO ACCOMODATE HIGH STATIC PRESSURES AND EXPLOSIVE SHOCK. TESTING WILL DEMONSTRATE THESE SENSORSHAVE THIRTY DB MORE SENSITIVITY AND DYNAMIC RANGE THAN CONVENTIONAL PIEZOELECTRIC HYDROPHONES OVER THE AUDIO FREQUENCY RANGE. ANALYSIS WILL BE PERFORMED TO SHOW THE COST TO FABRICATE, TEST, AND CALIBRATE THE SENSORS IS LOW BECAUSE OF HTG/N-S PROPRIETARY DESIGN AND PATENTEDSILICON MICROMACHINING TECHNOLOGY. MAJOR COST SAVINGS ARE EXPECTED FOR LARGE ACOUSTIC ARRAYS AT BOTH THE COMPONENT AND SYSTEM LEVELS. THE SENSOR-S LONG-TERM STABILITY AND VERY LOW SENSITIVITY TO OCEAN TEMPERATURE AND PRESSURE WILL BE DEMONSTRATED. FOR ULTRA HIGH-SENSITIVITY RESEARCH APPLICATIONS, A SENSOR ARRAY CAN BE HOUSED IN ONE PACKAGE, THE OUTPUTS AVERAGED, OR RESONANT TUNED CIRCUITS USED TO ENHANCE S/N AND EXTEND DYNAMIC RANGE.