| Vital signs can feed back the health of the living body and determine whether the living body exists.The respiration and heartbeat are the most important indicators of vital signs.The technology of vital signs detection based on Doppler radar has strong anti-interference ability and is not easily affected by the external environment.It can be widely used in search and rescue,medical monitoring and health monitoring.Therefore,the research on the technology of vital signs detection based on Doppler radar has very important significance and wide practical value.At present,there are still some problems to be solved in the technology of the vital signs detection based on Doppler radar,such as solving the problem of null detection point to improve the detection accuracy,solving the false alarm caused by random movement,and extracting cardiopulmonary information from strong harmonic interference.In this paper,the research on the technology of vital signs detection based on continuous-wave(CW)Doppler radar is carried out to solve the problem of null detection point and its practicality.The specific work is as follows:1.The basic theory and technical difficulties of continuous-wave(CW)Doppler radar vital signs detection is studied.Through the investigation of the technology of vital signs detection,and the technical difficulty in null detection point has been fully studied.The working principle,advantages and disadvantages of the two kinds of vital signs detection structures(super-heterodyne structure and direct conversion structure)are analyzed,and the two structures are simulated to detect vital signs using Simulation software.2.The novel transceiver with concurrent dual-band hybrid down-conversion architecture is proposed.The dual-band continuous-wave(CW)Doppler radar detection system with frequency of 2.05 GHz and 1.64 GHz is designed.The entire radar transceiver system is built to simulate the real environment and verify the system scheme in Simulation software.3.The dual-band continuous-wave(CW)radar vital signs detection system is realized.The work mainly includes RF transceiver circuit,microstrip patch antenna,data acquisition and processing,and so on.Experiments show that the vital signs detection radar designed can solve the problem of null detection point,and can truly restore the respiration and heartbeat,which can meet the needs of vital signs detection,and the error rate is 3.11% in this paper.4.The performance of dual-band detection radar is studied for different application scenarios.In order to detect the actual application of the system,the living body is subjected to the detection of vital signs under two situations of exercising and obstacle.The detection results show that the radar detection system designed can obtain real cardiopulmonary information in the above two environments,and the error rates are 4.43%and 6.64%,respectively in this paper. |
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