Phased-MIMO Radar With Frequency Diversity for Range-Dependent Beamforming

Phased-multiple-input and multiple-output (MIMO) radar is a flexible technique which enjoys the advantages of MIMO radar without sacrificing the main advantage of phased-array radar. However, the phased-MIMO radar is limited to range-independent directivity; this limits the radar performance to mitigate non-desirable range-dependent interferences. In this paper, we propose a new phased-MIMO radar with frequency diversity for range-dependent beamforming. The essence of the proposed technique is to divide the frequency diverse array transmit array into multiple subarrays, each subarray coherently transmits a distinct waveform with a small frequency increment across the array elements. Each subarray forms a directional beam and all beams are independently steerable by tuning the frequency increment. The subarrays jointly offer flexible operating modes and range-dependent beamforming. The beamforming performance as compared to phased-MIMO radar is examined by analyzing the transmit-receive beampatterns and the output signal-to-interference-plus-noise ratio. The effectiveness of the proposed technique is verified by numerical simulation results.