Considerations on Near-Field Correction: µm Accuracy with mmWave Radar

Recent advances in millimeter-wave (mmWave) hardware have enabled radar distance measurement with unprecedented precision. Despite this progress, achieving µm-level accuracy with mmWave radar remains a significant challenge. What is a purely geometrical problem in optics is complex when dealing with longer wavelengths. The far-field concept of measuring points in space is impaired by the presence of nearfield effects. In this work, we review available near-field models and we introduce a closed-form model, designed for both the Fraunhofer and the Fresnel region. Finally, we show to what extent the proposed model allows for the correction of mmWave radar measurements.