Millimetre-Wave FMCW Radar Thickness Measurement under Environmental Vibration Using Hardware Synchronization and Reference Reflector Compensations

Millimetre-wave FMCW radar enables non-contact, high-precision thickness measurement in industrial environments, offering improved safety and robustness compared to conventional methods. However, achieving micrometre-level accuracy is challenged by phase noise, frequency drift, and vibration. This study experimentally quantifies the impact of oscillator phase noise and environmental vibration on FMCW radar-based thickness measurement. We demonstrate that reference reflector compensation and hardware synchronization significantly improve measurement accuracy, achieving 12.5 µm precision under simulated industrial vibration (0.1 G, 20 Hz). These results clarify the effectiveness of synchronization and compensation techniques for reliable thickness measurement in dynamic conditions.