Distance-compensated near-field MIMO millimeter-wave imaging for security and industrial applications

A distance-compensated near-field MIMO mm-wave imaging algorithm is proposed to mitigate amplitude mismatches that arise from varying target-to-aperture distances. By retaining the distance-based attenuation factor in the scattered field model and incorporating a dimensionality-reduction strategy in the wavenumber domain, the method accurately corrects phase and amplitude distortions while substantially reducing the computational cost. Simulations involving point targets and a Siemens star demonstrate that the proposed approach achieves higher image quality than conventional algorithms, along with a considerable decrease in reconstruction time. Experimental validations using a mechanically scanned MIMO radar confirm that the method preserves key geometric features under near-field conditions, such as concealed weapon scenarios, while significantly lowering the processing load. The algorithm's straightforward implementation allows seamless integration into existing MIMO mm-wave systems, making it suitable for near-real-time security inspection and industrial applications requiring high-fidelity 3D reconstruction. The proposed imaging system synergistically combines a radar-on-chip device with a sliding rail platform, establishing a planar synthetic aperture radar (SAR) architecture. This approach coordinates the virtual channel characteristics of a linear MIMO array with mechanical scanning operations, achieving high-resolution imaging while significantly reducing hardware complexity.