Airborne Polarimetric Doppler Weather Radar: Antenna Aperture and Beam Forming Architecture

Radar performance depends on antenna characteristics, transmit power, transmit waveform and receiver design. Phased array radar (PAR) with solid-state amplifiers, attenuators and phase shifters uses additional signal processing schemes for achieving desired sensitivity, scan rate and data quality than in the case of a mechanically scanning radar that uses high-power klystron, magnetron or traveling wave tube transmitters. Active electronic scanning array (AESA) enables rapid scanning - the radar beam could be steered to any angular direction nearly instantly. Transmit and receive beam characteristics of AESA could be made independent of each other by an appropriate amplitude and/or phase weighting of the individual radiating element transmit and receive signals. Rapid steering of the antenna beam is suitable for beam multiplexing (BMX). BMX enables the collection of independent sample pairs of radar signals that reduce errors in radar measurements while providing rapid updates of scan volumes. Scan strategies for pencil beam and broad beam configurations are presented with regard to collecting reflectivity and radial velocity within a specified standard deviation of error. Beamforming radar architectures for pencil beam and broad beam configuration are described.