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.@en

Future and emerging radar systems are experiencing growing reliance on MIMO functionality in order to support demand for finer resolution and greater data collection under increasingly stringent spectral requirements. In order to support MIMO functionality while preserving spectral usage requirements, pseudo-orthogonal waveform sets are desired. In order to balance the complicated and often contradicting parameter requirements involved in creating pseudo-orthogonal waveform sets, a particle swarm-based optimization technique is introduced. This technique is shown to be applicable to several types of pseudo-orthogonal code sets, including a polyphase coded waveform set and a non-linear frequency modulated waveform set formed utilizing a novel parameterization method.@en