Side-looking Stripmap SAR Based on Vortex Electromagnetic Waves

The side-looking vortex stripmap synthetic aperture radar (SAR), based on the vortex electromagnetic (EM) waves, is developed to achieve two-dimensional (2D) target profiles. Firstly, the pulse compression in the fast time domain is conducted to obtain the range information, and then a newly matched filter in the azimuthal direction is designed according to the vortex EM wave's characteristics. Finally, the target profiles are obtained after the azimuthal pulse compression. Theoretical and simulation results indicate that the side-looking vortex stripmap SAR can differentially characterize target within the beam more distinctly than conventional SAR technique. With the increase of orbital angular momentum (OAM) mode number, it has the ability to enlarge the observation area while improving the azimuthal resolution at the corresponding different pitch angle positions relatively. This work can benefit the applications of OAM-carrying waves in radar realms as well as the development of the 2D imaging technology.