The microwave or millimeter-wave imaging systems and techniques described in this invention disclosure form the basis for highly effective, real-time, near-field, imaging systems that may be used for security screening of concealed objects and many other applications. The imaging array architecture uses a sparse array configuration that builds upon established multistatic boundary array methods to allow formation of high-resolution imaging arrays that require only a modest number of antenna elements and simplified signal distribution networks. Our approach differs from established methods by expanding the versatility of the approach to non-planar configurations, providing greater modularity, supporting very wide bandwidth operation, operating effectively in the near field of the arrays, while simultaneously providing more efficient image formation. This modular multistatic sparse array architecture coupled with the efficient image reconstruction algorithm has been demonstrated in a fully operational 2D array imaging configuration designed for personnel security screening. This real-time system produces high-resolution imagery at 23 frames per second.