The modern advancements in digital electronics allow waveforms to be easily synthesized and captured using only digital electronics. The synthesis of radar waveforms using only digital electronics, such as Digital-to-Analog Converters (DACs) and Analog-to-Digital Converters (ADCs) allows for a majority of the analog chain to be removed from the system. In order to create a constant amplitude waveform, the amplitude distortions must be compensated for. The method chosen to compensate for the amplitude distortions is to pre-distort the waveform so, when it is influenced by the system, the output waveform has a near constant amplitude modulus. The effects of the predistortion were observed to be successful in both range and range-Doppler radar implementations.@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

This paper considers wideband beamforming and waveform design for transmission from advanced multiple channel radar systems. Hence, this paper describes the initial designs of a wideband transmit beamformer for a multi-channel high resolution radar, applicable to airborne and spaceborne radars. As a case study for this paper, we use the EcoSAR instrument developed by NASA Goddard Space Flight Center for the measurement of science parameters. The wideband EcoSAR employs two multi-channel antennas and full transmit and receive digital beamforming to generate high resolution images of the ground features. Maintaining a consistent beampattern when the bandwidth is approximately 50% of the center frequency is a challenge. Breaking this nexus relies on optimum beam weight design and accompanying waveform design; not merely the former as is typically done. The approaches of this paper have shown how the beampatterns can be maintained while meeting beam requirements.@en