Chipless Tag Identification in Cluttered Environments through mm-Wave SAR Imaging

In the realm of self-localization and tracking systems reliant on frequency-coded chipless RFID infrastructure, the effective suppression of clutter is imperative for ensuring reliable tag detection, particularly in challenging and cluttered environments. This paper introduces a novel approach to address this issue by employing Synthetic Aperture Radar (SAR) technique. High-resolution SAR imaging has the potential to distinguish tags from the surrounding clutter. The proposed method relies on extracting the tag position in reference to SAR geometry. Based on the position, a cluttered environment is compressed within the time-domain data, allowing the unique ID of the tag to be extracted from its corresponding frequency-domain response. The proposed methodology is experimentally validated in the W-band (75 GHz - 110 GHz) using a frequency-coded trihedral corner reflector, where the code was designated using a triangle Dielectric Resonator (DR) array. To exemplify a clutter scenario, a large metal reflector was placed directly behind the tag. Contrary to other methods in the literature, the results of this study conclusively demonstrate the efficacy of SAR processing for clutter mitigation in various tracking systems.