Wideband Millimeter-Wave Short-Range Imaging: A K-Space Spectral Integration Approach and Comparative Analysis

Millimeter-wave near-field imaging is increasingly vital for security and inspection applications, yet achieving high-quality images remains a challenge. This article presents a wideband k-space spectral integration (WK-SI) approach that enhances imaging quality at a single frequency. By leveraging the varying wavenumber characteristics of wideband signals, the proposed method synthesizes a comprehensive spectral coverage within the k-space. This process exploits coherent superposition to compensate for near-field phase discrepancies, thereby filling the spectral voids that typically compromise single-frequency reconstructions. Numerical results indicate that, compared with conventional algorithms such as back-projection algorithm (BPA) and range migration algorithm (RMA), the proposed method achieves clearer images and improves artifact suppression.