Millimeter-Wave Contactless Vital Sign Monitoring Using Dynamic Metasurface Antenna

In this letter, we experimentally present a customized hardware framework to implement contactless millimeter-wave (mmWave) vital sign sensing in the 60 GHz license-free industrial, scientific, and medical band using a dynamic metasurface antenna (DMA). The proof-of-concept experiment highlights how mmWave RF sensing challenges can be addressed through the pattern diversity of a DMA-assisted setup, eliminating the need for commercial Wi-Fi routers or reflecting surfaces. The measured results demonstrate that mmWave signals can be precisely steered toward the human body, and analysis of the reflected signals enables accurate estimation of breathing and heart rates. The reflected signal strength exceeds ambient noise by over 30 dB, supporting reliable vital sign sensing over the mmWave channel. We experimentally evaluate breathing and heart rates using the magnitude signature of measured channel state information in a realistic indoor environment. Experimental results demonstrate low mean absolute errors for both respiration and heart rate compared to ground truth sensor data. The proposed DMA-assisted mmWave testbed unlocks the potential for the practical deployment of various mmWave sensing applications, such as fall detection, gait recognition, human localization and spatial tracking, and real-time vital sign monitoring in dynamic environments, as well as integrated sensing and communication.