1 Introduction

Human vital signs are usually measured through monitoring systems that historically have relied on wired connections to a patient’s body to report heart and breathing rates through a combination of electrocardiogram and oxygen saturation sensors. These sensors can be difficult to keep in constant contact with newborns, severely burned patients, those who suffer from epilepsy or patients in psychiatric wards. For those patients who are mobile, monitoring vital signs can be challenging as the patient moves around their home.

A millimeter-wave (mmWave) radar sensor can detect very fine movements, even from a patient’s chest. Since chest movements are affected by both breathing (fundamental frequency) and heart-rate movement (additional harmonics), the fine measurement of chest movements enables contactless measurement of vital signs.

The primary enabler of this functionality is the ability of the sensor to detect the position and speed of a patient’s chest through a combination of frequency modulated continuous wave (FMCW) sensing and multiple input, multiple output (MIMO) antenna radar systems.

The sensor can also detect movements in bed and inform caregivers of potential bed sores, or even monitor multiple patients at once, such as an elderly couple. Additionally, a mmWave sensor can detect a person falling and notify caregivers in real time.