Millimeter-Wave Imaging via Circular-Arc MIMO Arrays

Millimeter-wave (MMW) imaging has a promising prospect in application of concealed weapons detection. To that end, we propose a circular-arc multiple-input–multiple-output (MIMO) array scheme with uniformly spaced transmit and receive antennas along the horizontal-arc direction while scanning along the vertical direction. The antenna beams of the circular-arc MIMO array can provide more uniform coverage of the imaging scene than those of linear or planar MIMO arrays, which is especially important for the detection of concealed weapons carried by personnel. Furthermore, a near-field 3-D imaging technique, based on spatial frequency-domain processing, is presented together with a detailed analysis of sampling criteria and resolutions. Numerical and experimental results are provided to demonstrate the performance of the proposed method in comparison with those of the currently most used array schemes and imaging algorithms.