Suppressing Beam Squint Effect For Near-Field Wideband Communication Through Movable Antennas
In near-field broadband MISO systems, movable-antenna (MA) arrays suffer from beam squint, causing inconsistent analog beamforming gain across the entire bandwidth. To address this, this work pioneers the use of physical antenna displacement as an additional controllable degree of freedom. We propose a joint optimization framework grounded in near-field channel modeling, aiming to maximize the minimum analog beamforming gain over the full bandwidth. The problem is solved via a synergistic combination of the smoothed gradient descent-ascent (SGDA) algorithm and a relaxation-variable technique. Unlike conventional fixed-array designs, our approach dynamically reconfigures antenna positions to mitigate squint-induced gain variation. Under typical near-field conditions, it achieves up to a 3.2-dB improvement in the minimum broadband beam gain, significantly enhancing gain consistency and robustness. This establishes a novel paradigm for broadband near-field beamforming.