Near-field Communication Passive Wireless Measurement System And Wearable Point-of-care Testing Applications

With the rapid development of wireless sensor network,sensor and circuit integration into the hybrid system appeared in recent years,so as to complete the monitoring of various complex physiological signals of human body.Because most of these circuit systems need external power supply,they can not fully realize the flexibility and miniaturization of the system.Near Field Communication(NFC)technology,as a short-range radio technology,can realize fast Communication between devices.The NFC antenna and the mobile phone not only exchange data,but also generate power through inductive coupling to work in a passive and wireless manner.Point-of-care Testing(POCT)technology is a new detection method that can realize on-site detection at the occurrence of disease or event,without complex processing and operation process.The portable medical equipment is used to detect the physiological parameters of human body and can quickly obtain detection results.In the aspect of system design,passive wireless measurement technology and POCT detection technology are applied in this paper to realize the passive wireless measurement system based on NFC with smart phones.The NFC circular antenna is designed and simulated.Compared with the NFC rectangular coil,the circular coil is more suitable for the wearable design of the human body.At the same time,the circuit system is flexible and stretchable,so as to cope with the application scenarios close to the skin and meet the special needs of the crowd.It is specifically applied to two aspects of flexible wearable research:(1)First of all,according to the pulse signal of the human body,the use of photoelectric volumetric pulse Graphy(PPG)to detect the heart rate signal detection under different states of the human body(rest state,movement state,working state),Pulse Rate Variability(PRV)analysis of heart Rate signals is carried out,and the final results are presented in the smart device.(2)Secondly,Polyvinylidene Fluoride(PVDF)piezoelectric membrane sensor was used to monitor the fetal movement signals of pregnant women in both lying and sitting positions.By building the corresponding measurement system,the results will be sent to the smart phone.The measurement system can quickly and accurately monitor human signals,which is easy to carry and more convenient in operation.It is particularly prominent in the wearable design with low cost and easy operation.Finally,the experiment shows that the NFC passive wireless measurement system designed in this paper is applied to the wearable design of human body through real-time detection technology and flexible electronic technology.The corresponding heart rate signals can be obtained successfully under different states,and the fatigue and pressure under different states are analyzed.The error between the detected fetal movement signal and the subjective fetal movement count was less than 10%.It is also proved that the passive wireless measurement system can play a role in the wearable monitoring of human physiological signals,which provides great convenience for people to monitor physiological signals at home.