Instrument for Measuring Millimeter-Wave Polarimetric Bidirectional Reflectance Distribution Function

This proposal develops a new instrument to fully characterize radio-wave interactions in all angles and polarizations at frequencies between 40 and 220 GHz. The instrument's deployment to Department of Defense (DOD) test facilities and to civilian research facilities will accelerate understanding of how target objects interact over extended frequency bands, and will in turn enable radar and communication system development in these bands. Antenna motion is achieved by a combination of tilt and position control, with a path-calibrating feature to achieve the required sub-millimeter accuracy in the propagation direction. Using existing RF modules designed for vector network analyzer (VNA) frequency extension, coupled with an SA Photonics baseband RF system adapted from our fiber-optic gyroscope (FOG) products will support the wide range of frequencies of interest to military and commercial customers. Modular software controls positioning, RF frequency and noise managment, calibration, measurement interpolation, coordinate transformation and presentation. The result is a fully automated, script-able system capable of acquiring data for weeks at a time with continual calibration and no user intervention.