A novel imaging formation method for electromagnetic vortex SAR based on orbital-angular-momentum

摘要

Recently, electromagnetic (EM) vortex wave carrying orbital angular momentum (OAM) attracts more attentions in radar imaging, due to its ability of infinite degree of information modulation and realization of azimuth resolution without relative motion. Most of current research focuses on the staring imaging mode, where the radar is static relative to the targets and abundant OAM modes control is indispensable. Acquiring a high azimuth resolution image depends on massive OAM conversion, which brings stricter requirements for radar antenna. In this paper, a novel imaging algorithm of electromagnetic vortex synthetic aperture radar based on the Chirp-Scaling algorithm is proposed, where the radar is moving and OAM mode is constant. The introduction of moving radar leads to the update of geometry model and challenge of imaging formation. The SAR geometry model is adopted for EM vortex with OAM and the echo signal model is deduced simultaneously. Then the imaging algorithm of EM vortex-SAR is proposed. Software simulation and comprehensive numerical simulations validate the effectiveness of the proposed algorithm, which is beneficial for the further information-rich radar and radar target imaging.