Limits of Transmit Beamforming for Massive MIMO Radar

Massive MIMO has garnered a significant deal of interest recently. In this paper, we discuss the fundamental limitations of the resolution of beampatterns produced by MIMO radar when the number of antennas grows large-leading to a massive MIMO scenario in the context of radar. In particular, we examine whether any arbitrary beampattern can be formed as the number of antennas N increases, i.e., as N → ∞. We further study the improvement of the resolution of beampattern shaping as N grows large. This is to see if the potential of massive MIMO can be unleashed in active sensing and beamforming applications.