Vortex Electromagnetic Waves Based Synthetic Aperture Radar Interferometry Technique

Abstract

Synthetic aperture radar interferometry (InSAR), which is a combination of synthetic aperture radar (SAR) technique and interferometry technique, has been developed rapidly over several decades in Earth surface topography mapping and deformation detection. For conventional across-track InSAR, the baseline is a contradictory, because a large baseline will cause a high system sensitivity, but with a serious baseline decorrelation. Vortex electromagnetic (EM) waves with Orbital Angular Momentum (OAM) have been widely studied in the past decade for radar applications. Vortex EM wave presents to be a brand-new degree of freedom in SAR. In this paper, the OAM-based InSAR technique is proposed to obtain three-dimensional target information accurately without the existence of physical baseline. The OAM-based InSAR employs the interferometric phase of two OAM beams to derive the 3D information of the target. Because only one single OAM antenna is used to transmit and receive the two OAM beams, the baseline no longer exists, which could reduce the requirement of InSAR platform and eliminate the effect of baseline decorrelation. Moreover, without the steps of image registration and interferogram flattening, the process of the OAM-based InSAR is simpler. Simulation results demonstrate the effectiveness of the proposed technique and indicate that vortex EM waves can be exploited to obtain three-dimensional target information with high accuracy.