Localisation of concealed worn items using a millimeter wave FMCW radar

In this paper, the setup of a rotating 94 GHz millimeter wave FMCW radar for passenger inspection on airports is presented. The radar frontend comprises 5 receive channels in order to look the person under test from different aspect angles. A special focus is on the calibration of the integrated VCO of the radar module. Its non-linearity has to be compensated precisely. Else, the phase of the intermediate frequency signal gets distorted which degrades the image resolution. Test measurements performing a 360 degree scan show the ability of the scanner to detect and localize dangerous metallic as well as non-metallic objects worn concealed under the cloths.