Wireless non-contact measurement of human's heartbeat and bloodflow with microwave interferometry

Abstract

We present a technique for measuring human's heart beat and blood flow. The technique is based on interferometry at radio frequency (RF) and can produce very fine resolution and fast response. RF interferometry is a process detecting the change of phase and capable of resolving any physical quantity being measured within a fraction of the operating wavelength. It has relatively faster system response time than other techniques due to the fact that it is typically operated with a single-frequency source rather than across a frequency range. In measurement of heart beat and blood flow in the human body, a RF signal is used as the irradiating source and the change of the phase of the return signal over time is detected in the signal processing. This phase change is processed to extract the Doppler frequency shift used for calculating the heart beat or blood flow. Accurate wireless non-contact measurement of human's heart beat and blood flow with RF interferometry will advance the practice of medicine and promise substantial benefits to patients and medical professionals.