QCTO Luneburg Lens-Based Retroreflective Tag Landmarks for mm-Wave Self-Localization Systems

This paper presents a novel passive frequency-coded retroreflective tag landmark (radar target) based on a flattened quasi-conformal transformation optics Luneburg lens enabling an extreme field-of-view angle. A three-dimensional photonic crystal structure with embedded high-Q resonators is exploited as a coding retroreflective surface at the bottom of the lens. The retroreflector’s performance is investigated at a frequency of 80 GHz (W-band) enabling a precise mm-Wave indoor localization.