Ris-Aided Radar Imaging Utilizing the Virtual Source Principle

Synthetic Aperture Radar (SAR) is widely employed to generate radar images of large scenes by mechanically moving the antenna platform across or around the scene. However, at higher frequencies, such as terahertz (THz) domain, this approach becomes increasingly challenging, as motion errors as small as a few millimeters are directly translated into imaging errors. In this paper, we propose leveraging Reconfigurable Intelligent Surfaces (RIS) as a smart medium to synthesize a virtual source image that can be steered around the scene. This eliminates the need for platform motion, enabling radar imaging with even a static single-antenna system. Within this framework, the radar imaging process is redefined as a virtual source imaging problem and modeled in the wavenumber domain. Furthermore, image formation algorithms are developed for both near field and far field scenarios.