Radar imaging by using GTD near-field model and antenna array-factor

In this paper, we present radar image constructing method using the AF theoretical and measured near-field of simple model such as 2-dimensional conducting strip and corner reflector. SAR algorithm is generally adequate in far and even if near-region. Therefore, antenna aperture length is not necessary to be so long for target in near region, simple and practical AF method alternatively becomes valid. This situation indicates surface penetrating radar such as mine-finding or wall-through sensor. Fortunately near-field modelling is not so difficult by using Geometrical Theory of Diffraction (GTD) or Uniform Asymptotic Theory of Diffraction (UAT) if target shape is simple. We show 2-dimensional model, for simplicity, using GTD/UAT and construct its image using AF and DAS algorithm for short range radar. As expected, examining theoretical and experimental results are so interesting. When span distance between radar and target is in near and Fresnel region AF-DAS image is more explicit than SAR and in far region both images are almost similar. In addition, by employing GTD/UAT near-field model, obtained image becomes to be clearer compared with far-field model.