Beamspace slow-time MIMO radar for multipath clutter mitigation

This paper concerns beamspace multiple-input multiple-output (MIMO) space-time adaptive processing (STAP) to mitigate radar clutter subject to multipath propagation between transmit and receive arrays. Transmit beams are phase-coded to be orthogonal after Doppler processing at the receiver (in "slow-time"). This permits separation and coherent recombination of transmit beams to form virtual transmit nulls in directions that would otherwise result in multipath clutter returns in the receive mainlobe. Compared to element-space methods, beamspace MIMO is particularly advantageous because physical transmit beams can be designed to efficiently illuminate a sector of interest as well as maintain a low transmit voltage standing wave ratio (VSWR).