Microwave Doppler Radar for Monitoring of Vital Sign and Rotational Movement

The microwave Doppler radar involves transmitting the microwave/RF signal towards the target, which gets reflected by the target object. The parameters representing the rotational or translational motion of the moving target are retrieved by down-converting the reflected modified RF signal in order to extract the corresponding frequency components. In this paper, a special type of microwave Doppler radar system consisting of a two-channel IQ receiver (one transmitter and two receivers) working in an S-band is designed to monitor the vital sign of human subjects and detect the rotational speed of objects. The system-level design and testing of the proposed bistatic IQ Doppler radar is carried out by fabricating and testing the individual RF components, including the power dividers and antennas. The especially designed bistatic Doppler radar system is used to detect the relevant parameters corresponding to the movement of two objects simultaneously by estimating precisely the frequency components of both the targets. The proposed microwave Doppler radars are tested at the system level by evaluating the heartbeat, including the chest movement of human subjects, and by extracting the rotational speed of circulating fans.