This contribution focuses on the limitations of Fourier-based imaging when applied to subsampled arrays used in multistatic millimeter-wave radar systems. The aim is to determine the relationship between the size of the object under test (OUT), its position with respect to the radar aperture, and the sampling requirements on the aperture so as to recover aliasing-free images. Based on the analysis results, a method for recovering spectral information is proposed, the idea of which is to replicate the plane wave spectrum, and then apply a band-pass filter defined by a priori knowledge of the OUT size. For simplicity, the analysis is done in two-dimensional (2-D; range and cross-range dimensions). A simulation-based application is presented for validation purpose