Using FMCW Radar for Spatially Resolved Intra-Chirp Vibrometry in the Audio Range

Many applications require low-cost vibration monitoring. Here we present a robust method for spatially resolved non-contact vibrometry with frequency modulated continuous wave (FMCW) radar sensors. Our newly found technique uses an instantaneous phase evaluation, thus allows for measuring faster than the radar sensors chirp rate. We verified our theory with experiments using an 80 GHz highly synchronous ultra-wideband mmWave radar system. In this way, we reached sub-micrometer measurement precision with vibration frequencies up to 16 kHz. Furthermore, we showed that our method enables a clear separation of various vibrating radar targets.