THE PROPOSED RESEARCH SEEKS TO DEVELOP PHOTONIC INTEGRATED CIRCUITS (PIC) FOR WIDELY TUNABLE AND HIGH-SENSITIVITY MICROWAVE AND MILLIMETER-WAVE RADIOMETRY. CAPABILITIES SURPASSING STATE OF THE ART WILL BE DEMONSTRATED BY EXPLOITING THE PRONOUNCED PHOTONIC ELECTRO-OPTIC AND PIEZOELECTRIC PROPERTIES OF THE ION-SLICED LITHIUM NIOBATE THIN FILM PLATFORM FOR MODULATION TUNABLE FILTERING AND DETECTION. THE PROPOSED PLATFORM IS FORMED BY THREE MAIN SUBSYSTEMS: (I) A WIDEBAND ELECTRO-OPTIC MODULATOR THAT UP-CONVERTS THE MICRO AND MILLIMETER-WAVE SIGNALS OF INTEREST BY MODULATING AN OPTICAL CARRIER; (II) A VOLTAGE-TUNABLE PHOTONIC FILTER THAT ADAPTIVELY SELECTS THE MILLIMETER WAVE SIDEBAND OF THE CARRIER; AND (III) A RESONANT OPTOMECHANICAL DETECTOR THAT PERFORMS THE POWER MEASUREMENT OF THE SPECTRALLY SELECTED SIGNALS. THE MODULATOR PHOTONIC FILTER AND RESONANT DETECTOR WILL ALL BE DESIGNED AND IMPLEMENTED USING MONOLITHICALLY FABRICATED LITHIUM NIOBATE CHIP-SCALE RESONATORS THAT CAN BE OPTICALLY AND PIEZOELECTRICALLY EXCITED SIMULTANEOUSLY. THE COHABITATION OF PHOTONS AND PHONONS IN A SINGLE RESONANT CAVITY OFFERS UNMATCHED CAPABILITIES IN DYNAMICALLY MODULATING QUASI-STATICALLY TUNING AND RESONANTLY ENHANCING THE TRANSFER FUNCTIONS OF THE BUILDING BLOCKS. UNPRECEDENTED TUNING RANGES IN MILLIMETER-WAVE CAN BE ACHIEVED BY HARNESSING THE FACT THAT EVEN A FRACTION OF TUNING AT OPTICAL FREQUENCIES TRANSLATES TO MULTI-OCTAVE BANDWIDTH AT RF. MOREOVER THE FUSION OF ON-CHIP ACOUSTICS AND PHOTONICS WILL YIELD FURTHER MINIATURIZED COMPONENTS OFFERING A VERY COMPETITIVE APPROACH WITH RESPECT TO THE STATE OF THE ART ALTERNATIVES. THE PROPOSED RESEARCH WILL ENABLE A FULL SOLUTION FOR PASSIVE MICROWAVE RADIOMETRY OVER A WIDE FREQUENCY RANGE (2-200 GHZ) WHILE MAINTAINING THE SPECTRAL SELECTIVITY (BW=0.1GHZ). THE SUBSYSTEMS WILL SEE APPLICATIONS IN EARTH AND PLANETARY SCIENCE AS WELL AS LIMB SOUNDERS AND AURORAL IMAGERS IN HELIOPHYSICS. EVEN THOUGH THE PROPOSED EFFORT FOCUSES ON MICRO- AND MILLIMETER-WAVE SIGNAL PROCESSING AND SENSING USING PIC THE THREE COMPRISING SUBSYSTEMS AND THEIR UNIQUE CAPABILITIES CAN BE USED INDIVIDUALLY FOR OPTICAL FREQUENCY DATA ACQUISITION IN NASA SCIENCE MISSIONS. ON-CHIP PHOTONIC RESONANCE AND MODULATION CAN ALSO SERVE AS STRONG BASIS FOR CONSTRUCTING LOW PHASE NOISE OPTOELECTRONIC OSCILLATORS (OEO).