Zero-Doppler Clutter Analysis and Imaging Algorithm Design for Near-Range Microwave Imaging With Elliptic Trajectories

The problem of achieving fast and accurate near-range millimeter wave imaging using synthetic aperture radar (SAR) systems with elliptic trajectories is discussed in this article. Compared with the conventional circular SAR systems that achieve better illumination of targets than linear SAR systems, the zero-Doppler clutter (ZDC) has significantly less impact on the image reconstruction results, which is analyzed analytically and numerically. For the image reconstruction, a computationally efficient algorithm based on array conversions is proposed. The proposed algorithm decomposes the elliptic SAR imaging problem into multiple circular SAR imaging subproblems and fast wavenumber domain techniques can be directly applied. Finally, the ZDC artifact suppression effects of the elliptic SAR systems and the performance of the proposed imaging algorithm are demonstrated with numerical simulations and experiments.