Grating lobe mitigation based on extended coherence factor in sparse MIMO UWB array

Many multiple-input-multiple-output (MIMO) ultra-wideband (UWB) array systems are restricted to a limited array with limited antenna elements and thus suffer from the azimuth grating lobes. To combat the azimuth grating lobes, in this paper, firstly a simple analysis about the grating lobes in the sparse MIMO UWB array is performed. Then, an extended coherence factor (ECF) method taking advantage of the frequency point flexibility of the stepped frequency continuous wave (SFCW) signals is proposed. Finally, numerical simulations are carried out and validate the proposed method.