Real time remote sensing systems of respiration and heart rates using doppler effect

Abstract

One of the medical world``s recent tendencies is to pursuit remote medical examination. With this tendency, the part of remote sensing technology has been studied by many laboratory members. Among the remote sensing technologies of patient, study about the wireless detection of respiration has studied from 1975[1]. And the detection of heart rate was started in 1979[2]. The remote sensing of patient using RP system is profitable in cost aspects compared with expensive medical instruments. Because the sensing system is easy to handle, even ordinary person who is not instructed about usage of the instruments can use it. Three systems are used on this study. Each system is consisted of antenna, transmitter, receiver and display part. The transmitter and receiver part for sensing both heart rates and respiration can be one or two parts. If it is consisted of two parts, the antennas used on the experiment must be two. But, if the transmitter and receiver part are integrated into one part, only one antenna is required on the experiment. It is consisted of coupler(or power divider), attenuator, LNA, circulator and mixer. The display part is consisted of analog-digital converter, amplifiers and filters. The real time and wireless life signal detecting systems are made by using Doppler Effect. These systems can measure respiration and heart rates with periodic movement of skin and muscle near the heart. The system is consisted of antenna, RF transmitter, receiver, and display part. I did the experiment at 1.9GHz, and 10GHz. The link budget about detecting systems is analyzed and the detected signal from the systems is compared with electrocardiogram(ECG) of monitor which is using for patient monitoring in hospital. And the detection of vital sign is also performed according to the different distances, and behind the wall.