Suppression of sidelobes in MIMO radar with distinctive piecewise non-linear frequency modulation sub-carrier

ABSTRACT

High sidelobes exist in normal multiple-input multiple-output (MIMO) radar waveforms, which utilize linear frequency modulation (LFM) or non-linear frequency modulation (NLFM) waveforms with the same subcarrier durations. Since the waveforms have the same expression, and each segment of the subcarriers can be only controlled by a few parameters to make them distinctive. This will cause comparatively high auto-correlation sidelobes in each zone of subcarriers. In order to suppress the sidelobes, new piecewise NLFM waveforms have been proposed in this paper. These novel MIMO radar waveforms are composed of three different kinds of subcarriers with totally different mathematical expressions. This is verified by the fact that the cross-correlation sidelobes between different subcarriers are much lower than the auto-correlation of each subcarrier. In addition, the number of MIMO radar waveforms has been improved significantly. As different subcarriers have their own controllable parameters, a genetic algorithm will be applied to generate the novel MIMO radar waveforms. Numerical results demonstrate the effectiveness that the auto-correlation sidelobes and the cross-correlation sidelobes of our proposed waveforms are reduced.