Enhanced resolution in MIMO-SAR imaging using apodization

When the conventional methods of sidelobe suppression are used in multiple input multiple output synthetic aperture radar (MIMO-SAR) systems to generate images for diagnosing the near field scattering features of targets, non-orthogonal sidelobes can hardly be suppressed efficiently. In this paper, based on the generation mechanisms of the non-orthogonal sidelobes in near filed, an approach which combines spatially variant apodization (SVA) with tri-apodization was proposed to suppress the non-orthogonal sidelobes for MIMO-SAR images. Simulation and experimental results demonstrate that the sidelobes in down range as well as the non-orthogonal sidelobes in cross range are suppressed efficiently via the proposed approach. As a consequence, for MIMO-SAR images, the resolutions in both the down range and the cross range are improved remarkably while a higher dynamic range can be achieved.