Terahertz Circular SAR Imaging Algorithm Based on the Extraction of Scattering Characteristics of Target Structures

This letter addresses the problem of changes in target shape and structure during imaging caused by different height structures being focused at the same height in the terahertz (THz) band. A new circular synthetic aperture radar (SAR) imaging algorithm based on the extraction of target structure scattering characteristics is proposed to solve this phenomenon. First, a circular SAR (CSAR) imaging model is established for different heights. The target was imaged at different heights, resulting in a series of image sequences in different heights and azimuth directions. Then, incoherent tracking of the backscattered energy is used to search for effective scattering centers at different heights. The scattering characteristic curves of different structures are obtained based on the effective scattering centers. Finally, the effectiveness of the proposed algorithm is verified by simulation and measured data. The proposed algorithm has accurately focused the target, while also enhancing the details. In addition, the contrast-to-noise ratio (CNR) of the imaging results has been improved by 4.87% compared to traditional algorithms.