RECENTLY, TECHNIQUES FOR ULTRA-WIDEBAND SPECTROMETRY HAVE BEEN PROPOSED WHICH WOULD ENABLE SIGNIFICANT NEW SCIENCE AND COULD SUBSTANTIALLY SIMPLIFY THE COMPLEXITY OF ATMOSPHERIC SENSING INSTRUMENTS. SPECIFICALLY, THE ULTRA-WIDEBAND PHOTONIC SPECTROMETER FOR PBL SENSING ACT-20 PROJECT IS DEVELOPING AN RF PHOTONIC SPECTROMETER FOR A MILLIMETER WAVE RADIOMETER BACK-END. SIGNIFICANTLY, THIS RF PHOTONIC SPECTROMETERS SHOULD OFFER AN ORDER OF MAGNITUDE INCREASE IN INSTANTANEOUS RF BANDWIDTHS COMPARED TO TODAY S SPECTROMETERS AND COULD PROVIDE AS MUCH AS 100-200 GHZ OF INSTANTANEOUS RF BANDWIDTH. WE PROPOSE TO BUILD AN RF FRONT-END THAT COULD LEVERAGE THE CAPABILITIES OF THE ULTRA-WIDEBAND PHOTONIC SPECTROMETER BY DEVELOPING A SINGLE-CHANNEL RF FRONT-END COVERING THE ULTRA-WIDE RF BANDWIDTH OF 20-200 GHZ. FOR THIS REASON, WE REFER TO THIS SYSTEM AS ULTRA RF . THIS FRONT-END WILL BE COMPRISED OF BROADBAND ANTENNA INTEGRATED WITH BROADBAND LOW NOISE AMPLIFIERS (LNAS) WHICH WILL BE FABRICATED IN NORTHROP GRUMMAN S ULTRA-HIGH FREQUENCY IACC25 MMIC TECHNOLOGY. THIS TECHNOLOGY FEATURES FT AND FMAX OF 750 AND 1500 GHZ, RESPECTIVELY. TO DEMONSTRATE VIABILITY, WE PROPOSE TO TEST THE FINAL RF FRONT-END WITH THE RF PHOTONIC SPECTROMETER BEING DEVELOPED ON THE ACT-20 PROJECT. THE ULTRA RF FRONT-END WILL BE INTEGRATED INTO A SINGLE ASSEMBLY TO MAINTAIN EFFECTIVE BANDWIDTH. THIS IS ESSENTIAL FOR COVERING THE 20-200 GHZ BANDWIDTH. THE ANTENNA WILL BE A DOUBLE RIDGED WAVEGUIDE HORN ANTENNA WITH A TRANSITION TO MICROSTRIP. THIS ALLOWS THE LNAS TO BE DIRECTLY INTEGRATED TO THE TRANSITION USING A WIREBOND. OUR SIMULATIONS SHOW THAT LOW NOISE AMPLIFIERS WITH GOOD SENSITIVITY CAN FEASIBLY OPERATE ACROSS THE 20-200 GHZ BANDWIDTH. WE WILL ALSO DESIGN 20-200 GHZ TRAVELING WAVE AMPLIFIERS (TWAS). THESE AMPLIFIERS HAVE HIGHER OUTPUT POWER COMPARED TO LOW NOISE AMPLIFIERS AND WILL BE NEEDED TO HANDLE THE AMPLIFIED NOISE POWER IN THE 20-200 GHZ BANDWIDTH AND TO DRIVE THE MODULATOR WITH ADEQUATE POWER TO INSURE HIGH DYNAMIC RANGE. INITIAL SIMULATIONS FOR THE HORN, LNA AND TWA ARE INCLUDED IN THE PROPOSAL. EXPERIMENTAL VALIDATION OF THE ULTRA RF FRONT-END WILL BE ESSENTIAL FOR VALIDATING THE SUCCESS OF THE PROJECT. VALIDATION IS COMPLICATED BY THE LARGE BANDWIDTHS, WHICH ARE NOT ACCOMMODATED BY ANY FORM OF COAXIAL INTERFACE OR WAVEGUIDE INTERFACE. THE ULTRA RF FRONTEND WILL BE VALIDATED BY BANDED RF MEASUREMENTS (RF AND RADIOMETRIC), AS WELL AS FINAL INTEGRATION WITH THE ULTRA-WIDEBAND RF PHOTONIC SPECTROMETER FOR DEMONSTRATION OF VIABILITY. IF SUCCESSFUL, THE ULTRA RF FRONT-END SYSTEM PAIRED WITH THE ULTRA-WIDEBAND RF PHOTONIC SPECTROMETER WILL ENABLE SIGNIFICANT REDUCTION IN SYSTEM COMPLEXITY, WHICH WILL REDUCE THE SIZE, WEIGHT, AND POWER OF DEPLOYED SYSTEMS AND WILL ENABLE DECADE BANDWIDTH ATMOSPHERIC SENSING NEEDED FOR PLANETARY BOUNDARY MEASUREMENTS.