Development of an All-Digital Polarimetric Phased Array for Future Multi-Function Radar Systems

The Multifunction Phased Array Radar (MPAR) program stands to deliver the most flexible long-range weather radar in history, featuring adaptive scanning as well as temporal resolutions more than ten times better than the WSR-88d. Many other future weather radar concepts and planned development efforts throughout the world make extensive use of dual-polarized phased array technology. Several technology demonstrators have been or are currently in development that seek to mitigate risks associated with the adoption of active phased array technology for weather radar applications. Most of these demonstrators are based on state-of-the-art analog beamforming technology from the last decade, namely that of digitized subarrays. This architecture is effective for applications with a low beam count and fixed aperture configurations, but is inherently limited in scalability and upgradeability over long periods of time. With the advent of low-cost, highly-integrated digital transceivers within the last decade, the technology landscape is on the cusp of providing a hardware solution for MPAR-like phased arrays that feature digitization of signals at the element level. This would provide the most scalable, upgradeable, and truly multifunctional phased array architecture for a system that is to be fielded for decades, but it is not without technical and cost risks associated with the adoption of element-level digital technology. The OU Horus project seeks to leverage several recent breakthroughs in the capabilities of on-chip digital transceivers, density of I/O and processing in FPGAs, and T/R module integration costs to demonstrate that a fully digital approach to these systems is not only viable from an engineering standpoint, but can be competitive from cost, integration/service, and power perspectives as well. This presentation will highlight progress in the development of an 8x8-element line replaceable unit (LRU) as part of the first stages of this project, focusing on the unique aspects of the project relating to dual polarization and beamforming calibration for accurate weather radar polarimetry, low-cost integration and thermal management, digital beamforming and control/communication subsystems, and antenna and T/R module electrical designs.