Non-contact mmWave Physiological Sensor in Eyewear Based on Spoof Localized Surface Plasmons

We develop a compact physiological sensor based on spoof localized surface plasmons (LSPs) to simultaneously detect blinks and heartbeats from the temporal region of the human head by attaching the sensor to eyewear. A double-layer spoof plasmonic resonator is integrated with a 24-GHz transceiver and a microcontroller unit (MCU) on a flexible printed circuit board (fPCB). Motions of the skin caused by blinking and heartbeat modulate the dielectric environment around the sensor, which are sensitively transduced into phase variations of the continuous wave signals from the spoof plasmonic resonator, which can be transmitted to a display device via Bluetooth. Experimental results demonstrate that the sensor is capable of providing accurate physiological monitoring with an average error of 11 ms for blink interval and 21 ms for averaged individual heartbeat interval.