Contour reconstruction and accurate identification of dielectric objects placed on a conducting surface are the aims of the millimeter-wave Synthetic Aperture Radar (SAR) imaging processing system presented in this paper. The method uses multiple frequencies, multiple receivers and one transmitter in a portal-based configuration in order to generate the SAR image. Then, the information in the image is used to estimate the contour of the body under test together with the permittivity of the dielectric region. The results presented in this paper are based on synthetic scattered electromagnetic field data generated using an accurate Finite-Difference Frequency-Domain (FDFD)-based model and inversion based on a fast SAR inversion algorithm. Representative examples showing the good behavior of the method in terms of detection accuracy are provided.
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