Radar-Based Tomographic Imaging of Inhomogeneous Structures with Filtered Backprojection Algorithm

In this contribution a tomographic imaging system using a broadband frequency modulated continuous wave (FMCW) radar system operating from 126–182 GHz is presented. The system consists of two parabolic mirrors to focus the beam and investigate objects in the area of the focal point. Moreover, the setup is based on the parallel-beam geometry, containing multiple electrical translation stages and a turntable to measure from various positions and angles. The tomographic reconstruction follows a monostatic approach, analyzing reflections from a metallic plate in terms of attenuation and time shift caused by the object itself. A 3D-printed cylinder made of polylactic acid (PLA) with an eccentrically arranged hole was used to investigate the utilization of the reconstruction algorithm on inhomogeneous objects. The image processing is based on the filtered backprojection algorithm, which is mainly used for computed tomography (CT). The results show promising potential and provide the basis for further investigations.