  Multiple-input multiple-output (MIMO) array based millimeter-wave (MMW)
imaging has a tangible prospect in applications of concealed weapons detection.
A near-field imaging algorithm based on wavenumber domain processing is
proposed for a cylindrical MIMO array scheme with uniformly spaced transmit and
receive antennas over both the vertical and horizontal-arc directions. The
spectrum aliasing associated with the proposed MIMO array is analyzed through a
zero-filling discrete-time Fourier transform. The analysis shows that an
undersampled array can be used in recovering the MMW image by a wavenumber
domain algorithm. The requirements for the antenna inter-element spacing of the
MIMO array are delineated. Numerical simulations as well as comparisons with
the backprojection (BP) algorithm are provided to demonstrate the effectiveness
of the proposed method.
