  This paper proposes a polyline shaped array based system scheme, associated
with mechanical scanning along the perpendicular direction of the array, for
near-field millimeter-wave (MMW) imaging. Each section of the polyline is a
chord of a circle with equal length. The polyline array, which can be realized
as a monostatic array or a multistatic one, is capable of providing more
observation angles than the linear or planar arrays. Further, we present the
related three-dimensional (3-D) imaging algorithms based on a hybrid processing
in the time domain and the spatial frequency domain. The nonuniform fast
Fourier transform (NUFFT) is utilized to improve the computational efficiency.
Simulations and experimental results are provided to demonstrate the efficacy
of the proposed method in comparison with the back-projection (BP) algorithm.
