Radon Transform Approaches in FMCW-Based-Sub-THz Tomography

This paper demonstrates the use of two FMCW radars operating at a center frequency of 243.6 GHz to generate tomographic images of an object under test. The FMCW radar principle is used to measure the Radon projection. Unlike the standard Radon transform, this method allows the use of either attenuation or phase as the reconstruction quantity, with phase being particularly beneficial for low-permittivity materials. The tomographic image is reconstructed using the filtered back-projection method to solve the inverse Radon transform problem. To enhance the signal-to-noise ratio and improve wave focusing, two converging lenses are employed in the measurement setup.