Efficient Wavenumber Domain Processing for Near-Field Imaging With Polyline Arrays

We propose an efficient wavenumber domain approach for polyline array-based millimeter-wave imaging. The polyline multiple-input–multiple-output (MIMO) array provides more uniform illumination of the target than the planar MIMO array while enjoying the planar array’s easy manufacturing. However, no existing efficient imaging algorithms deal with such an array topology. This article presents an approach that first implements a polyline-to-arc transformation on the polyline array, accompanied by a phase calibration method to maintain the transformation precision. The wavenumber domain technique is then employed to perform image reconstruction. This processing enables the transformation of the polyline array scheme into a monostatic cylindrical aperture, for which efficient imaging algorithms exist. The imaging performance and computational efficiency of the proposed approach are demonstrated with both simulations and experiments.