Three Dimensional Electromagnetic Vortex Radar Imaging Based on the Modified RD Algorithm

The vortex electromagnetic (EM) wave carrying orbital angular momentum (OAM) is promising to benefit the higher degree of freedom for synthetic aperture radar (SAR) imaging. Combining the traditional two-dimensional (2D) SAR and the vortex EM wave, vortex SAR can obtain the three-dimensional (3D) information to realize 3D imaging. This letter proposes a novel 3D vortex SAR imaging method based on the vortex EM wave to obtain 3D target information. First, a vortex SAR imaging model is established by the proposed 3D imaging algorithm. Then, the modified range-doppler (RD) algorithm is therefore proposed to reconstruct the target's profiles. The objective of the 3D RD algorithm is to decompose the time-domain correlation operations of the SAR 3D space into three independent one-dimensional correlations and then perform separate focusing processing on each dimension. Finally, the 3D information of the targets can be obtained according to the modified RD algorithm. The point target simulation is performed in this paper. The simulation results establish the effectiveness of the proposed technique. This paper lays the groundwork for the development of vortex EM waves in the field of 3D radar imaging.