A G-Band SAR System for Non-Destructive Inspection of Packaged Products

This work presents a high-resolution synthetic aperture radar (SAR) system operating at 182 GHz–202 GHz with a 20 GHz bandwidth for non-destructive quality control applications. The frequency modulated continuous wave (FMCW) radar frontend, based on monolithic microwave integrated circuits (MMICs), is mounted on a motorized linear rail to synthesize an aperture in cross-range direction. Backprojection processing is applied to frequency domain data to reconstruct two-dimensional images. Measurements demonstrate that the system achieves a cross-range resolution of 1.8 mm and a range resolution of 7.3 mm and enables imaging through common packaging materials such as paper and plastic. Fine surface features of a chocolate bar and the internal structure of packaged goods are resolved, and missing items inside sealed boxes are successfully detected. These results highlight the potential of G-band SAR imaging as a non-ionizing and contactless method for industrial inspection and quality assurance.