  Digital beamforming and waveform generation techniques in MIMO radar offer
enormous advantages in terms of flexibility and performance compared to
conventional radar systems based on analog implementations. To allow for such
fully digital design with an efficient hardware complexity, we consider the use
of low resolution digital-to-analog converters (DACs) while maintaining a
separate radio-frequency chain per antenna. A sum of squared residuals (SSR)
formulation for the beampattern and spectral shaping problem is solved based on
the Generalized Approximate Message Passing (GAMP) algorithm. Numerical results
demonstrate good performance in terms of spectral shaping as well as
cross-correlation properties of the different probing waveforms even with just
2-bit resolution per antenna.
