Application of waveform weighting for a frequency- invariant transmit beampattern

Advanced radar systems rely on multichannel, wideband operation. NASA's Ecosystem SAR (EcoSAR) and second-generation digital beamforming SAR [1]-[3] use active array architectures, where an active array radar system contains independent transmit and receive chains with unique amplifiers for each antenna element in the multichannel system. These radar systems have an independent arbitrary waveform generator for each channel and are designed to address wideband transmit beamforming. Unlike conventional narrowband beamforming, which only require a unique set of beamsteering coefficients per look angle, wideband beamforming requires beamsteering coefficients that vary with both look angle and frequency.