Phase-Only Pattern Synthesis via Semidefinite Relaxation for Clutter Suppression in Cognitive Airborne Radar

Beam pattern synthesis is a commonly employed spatial filtering technique for clutter suppression in airborne radar systems. The phase-only pattern synthesis method is proposed to achieve adaptive clutter suppression in airborne radar. Firstly, by exploiting the real-time environmental sensing capability of cognitive airborne radar, the desired antenna radiation pattern of the transmitted signal is optimized to realize equal-amplitude sidelobe suppression in diverse clutter environments. Secondly, an optimization model is formulated to minimize clutter echo power, and the semidefinite relaxation (SDR) method is applied to obtain the optimal phase weights. Finally, the effectiveness of the proposed method is verified through three simulations examples. The results demonstrate that the phase-only pattern synthesis approach significantly outperforms conventional techniques in terms of clutter suppression ratio, environmental adaptability, and operational stability. This work provides a robust and computationally efficient framework for improving radar performance in complex clutter scenarios.