Analysis on rank of channel matrix for monostatic MIMO radar system

Multiple-input multiple-output (MIMO) radar has shown its great potential on combating with target fades by averaging the target RCSs on many decorrelated channels, and hence significantly improves the system performance. The amount of decorrelated channels is mathematically represented by the rank of channel matrix. In this paper, an analysis on the rank of channel matrix for monostatic MIMO radar is given. It is found that the rank can be approximated by the bandwidth-aperture product. The sufficient condition to obtain a full-rank channel matrix is presented. As well, the effect of array structure on the rank is investigated. Sequentially, some suggestions are proposed to keep a large rank while using relatively small inter-sensor spacing. Finally, some simulations are given to verify the analysis.