A study of polarimetric phased arrays using the Digital Array Radar

The national network of weather radars (WSR-88D) is currently being upgraded with dual-polarization capabilities, facilitating many new areas of study in cloud and precipitation microphysics, and quantitative precipitation estimation and forecast, for example. Simultaneously, phased array technology is being investigated for its advantages related to rapid beam steering. In order for phased arrays to ever be considered for a future weather radar network, however, effective polarimetric capability must be possible. The Atmospheric Radar Research Center (ARRC), in collaboration with the IDEAS Laboratory at Purdue University, has been examining polarimetric phased array antenna characteristics, as well as developing algorithms to mitigate the effects of low-cost phased array system components. In order to achieve these objectives, the ARRC is using the Digital Array Radar (DAR) developed by the IDEAS Laboratory as a platform for detailed laboratory measurements. The DAR is a low-cost, reconfigurable, digital-at-every-element phased array system, and can be used to make flexible measurements for selection of polarization mode, polarization calibration, testing configurations such as cylindrical array, phase coding, and adaptive beamforming. An overview of the project, the DAR system, and preliminary measurements will be presented.