Beamforming with extended co-prime sensor arrays

Co-prime sensor arrays (CSAs) interleave two uniform linear subarrays that are undersampled by co-prime factors. The resulting nonuniform array requires far fewer sensors to match the spatial resolution of a fully populated ULA of the same aperture. Choosing the co-prime undersampling factors as close to equal as possible minimizes the number of sensors in the CSA. However, the peak side lobe of the CSA is higher than the peak side lobe of the equivalent full uniform linear array (ULA). Increasing the number of sensors in the CSA subarrays by half while maintaining the interelement spacing gurarantees that the CSA peak side lobe is less than that of the full aperture ULA when both arrays use rectangular windows.