High fill factor RF aperture arrays for improved passive, real-time millimeter wave imaging

摘要

Sensors operating in the millimeter wave region of the electromagnetic spectrum provide valuable situational awareness in degraded visual environments, helpful in navigation of rotorcraft and fixed wing aircraft. Due to their relatively long wavelength, millimeter waves can pass through many types of visual obscurants, including smoke, fog, dust, blowing sand, etc. with low attenuation. Developed to take advantage of these capabilities, our millimeter wave imager employs a unique, enabling receiver architecture based on distributed aperture arrays and optical upconversion. We have reported previously on operation and performance of our passive millimeter wave imager, including field test results in DVE and other representative environments, as well as extensive flight testing on an H-1 rotorcraft. Herein we discuss efforts to improve RF and optical component hardware integration, with the goal to increase manufacturability and reduce c-SWaP of the system. These outcomes will allow us to increase aperture sizes and channel counts, thereby providing increased receiver sensitivity and overall improved image quality. These developments in turn will open up new application areas for the passive millimeter wave technology, as well as better serving existing ones.