Non-contact and Real-time Pulse-based Radar for Vital-sign Monitoring

• Main Authors: HUANG, JIAN-YU, 黃健育
• Other Authors: CHANG, CHIA-HUNG
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/9fx37y

碩士 === 逢甲大學 === 電機工程學系 === 107 === In recent years, with the advent of aging society, the demand for health care has increased rapidly. In order to deal with this trend, it is necessary to develop a long-term medical device that is small in size, easy to carry, and low cost in manufacturing. Traditional medical instruments need to be in contact with a patient for diagnosis, but this step may cause physical or psychological discomfort to the patient. Therefore, the development of non-contact medical procedures, such as X-ray, computed tomography and magnetic resonance imaging systems. These instruments observe the internal tissues of the human body in a non-invasive manner, which can reduce the discomfort caused by the contact of the instrument during the medical process, but the disadvantage is that the operation is complicated and the equipment is expensive, the patient cannot use it by himself. In order to solve the above disadvantages, this thesis presents a noncontact and real-time pulse-based radar for vital-sign monitoring as the main research direction of the paper. The content of this radar system is discussed in the paper and used to measure human life signs such as breathing and heartbeat. It can be used for long-term medical care or to identify signs of life. First, a series of pulse signals generated by the transmitting front-end of the radar system are transmitted to the test subject through a microstrip array antenna. Due to the Doppler effect, the reflected signals will have human physiological signal due to the undulation or movement of the human chest. The receiver of the radar system demodulated a series of received pulse signals with LO signals, and processes the human breathing and heart rate to obtain instant human breathing and heartbeat waveforms. So as to make the radar system measurement more accurate, making the antenna into a set of microstrip array antennas, it is possible to have higher directivity. It is good for measuring weak signals such as heartbeat. Moreover, the radar using the technique of pulse width modulation in the transmitter helps adjust sensing energy, which in turn improves the overall signal-to-noise ratio (SNR), thereby increasing sensitivity. The prototype of this radar system architecture has a plane size of 100 mm × 50 mm and is printed on a fiberglass substrate (FR4) with a thickness of 1.6 mm. It includes a RF front-end circuit, a digital control circuit, and an analog processing circuit.