Enhanced Radar Imaging of Weak Targets in Sea Clutter via Spectral Filtering in k−ω Domain

Radar imaging of weak targets over the sea surface remains a significant challenge in the presence of sea clutter and low signal-to-clutter ratio (SCR) conditions. This paper proposes a spectral filtering (SF) technique designed to enhance weak target detection in radar imagery by exploiting the non-dispersive motion model of marine targets in the spectral (k–ω) domain. Assuming uniform motion, the proposed filter effectively suppresses clutter while preserving target signals. The method is specifically implemented for a 24 GHz Frequency Modulated Continuous Wave (FMCW) Multiple-Input Multiple-Output (MIMO) radar system, which enables rapid scene illumination and high temporal resolution without mechanical antenna rotation. The filtering performance of the proposed strategy is validated through both numerical simulations and experimental radar data. Results demonstrate that the proposed approach significantly improves detection capabilities under low SCR conditions, as confirmed by quantitative metrics and CFAR-based detection analysis.