Enhanced Electromagnetic Vortex Imaging Method Based on Multiaperture Array

Vortex electromagnetic waves possess intrinsic orbital angular momentum (OAM), providing an orthogonal degree of freedom that enhances information capacity. However, generating high-mode OAM beams requires stringent conditions, and their information-carrying efficiency is often limited, leading to constrained resolution. To overcome these limitations and achieve enhanced target azimuth information, improved degrees of freedom, and higher azimuth resolution, this paper proposes an OAM-position multiplexing Fourier ptychography (OPMFP) method. OPMFP synergistically integrates Fourier Ptychography (FP) with conventional electromagnetic vortex imaging. Firstly, an electromagnetic vortex propagation and imaging model incorporating OAM-position multiplexing is established. Secondly, the impact of phase error terms within the high-frequency echo model on imaging reconstruction fidelity is analyzed. Finally, leveraging the sampling framework of OPMFP in electromagnetic vortex radar, a high-frequency information recovery algorithm is proposed. Simulation results demonstrate that, compared to conventional electromagnetic vortex imaging, the proposed OPMFP method successfully reconstructs high-purity, high-mode information and delivers superior azimuth resolution performance even when employing vortex beams within a lower mode range.