Vortex SAR Imaging Method Based on OAM Beams Design

Vortex synthetic aperture radar (SAR), combination of the orbital angular momentum (OAM) beams and the stripmap SAR technology, is proposed to achieve higher azimuth resolution. Firstly, the imaging scenario and the echo model are established and derived. Secondly, the pre-processing approaches, including the amplitude compensation and the phase compensation, are developed by the design of the transmitted OAM beams. Then, an improved range-Doppler (RD) algorithm is proposed to acquire target's two dimensional (2D) profiles. Simulation results demonstrate the effectiveness of the proposed algorithm, and the influence factors of the azimuth resolution are analyzed as well. Compared with the conventional SAR, the proposed vortex SAR imaging method can achieve higher azimuth resolution with the same synthetic aperture length (SAL). This work can benefit the applications of OAM-carrying waves in radar realms as well as the development of high-resolution SAR imaging technique.