基于磁-电-声表面波非线性耦合的可穿戴全双工柔性无源无线磁传感器研究

Wearable device is the latest application of the Internet of Things (IoT), and it has very broad application prospects. Flexible sensor is the core of wearable device. As the most widely used sensor technology, the research of flexible magnetic sensor is very little. Flexible passive wireless sensor can fully satisfy the design requirements of wearable wireless sensor networks, owing to its integrated functions of sensing, flexibility, passive and wireless. Furthermore, flexible passive wireless sensor is also an important trend of wearable sensor technology development. However, the current flexible passive wireless sensor techniques mainly focus on the above mentioned functions independently. The researches on the relation especially the interaction of these functions are seldom discussed. In this project, we propose a novel flexible passive wireless magnetic sensor based on the magnetoelectric transducer and Surface Acoustic Wave (SAW) technology. The flexible passive wireless magnetic sensor has an integrative structure, which integrated with the functions of sensing, flexible, passive and wireless in one structure. Moreover, the proposed flexible passive wireless magnetic sensor can also achieve the full-duplex communication, which could solve the wireless communication distance bottleneck of SAW sensors. The research object of this project is the wearable magnetic sensor. The breakthrough point of this project is the study of flexible magnetoelectric transducer based on nonlinear coupling effect. The research means of this project is the study of flexible SAW technology with the new wave mode. The magneto-electro-surface acoustic wave nonlinear coupling mechanisms and the flexible SAW magnetic field sensing principles will be systematically studied. The physical mechanisms and technical methods of the full-duplex communication of passive wireless SAW magnetic sensor will be explored in this project. A theoretical design method of the proposed integrative full-duplex flexible passive wireless magnetic sensor will be also provided in this project. Finally, this project will provide theoretical and technical supports for the enhancement of intelligent wearable level of magnetic sensor.

可穿戴设备是物联网的最新应用，前景广阔。柔性传感器是可穿戴设备的核心。作为传感技术应用最广泛的磁传感器，柔性化研究极少。“柔性无源无线传感器”同时具备传感、柔性、无源和无线功能，完全满足可穿戴无线传感器网络的要求，是可穿戴传感技术发展的重要趋势。但现有柔性无源无线传感技术都是对这些功能独立研究，而对之间的联系，尤其是相互作用鲜有报道。本项目创新提出融合磁电换能和声表面波技术的柔性无源无线磁传感器，同时实现“一体化”设计和“全双工”通信，根本解决声表面波传感器的无线通信距离瓶颈。以可穿戴磁传感器为研究对象，以柔性磁电换能器的非线性研究为切入点，以基于新型波模式的柔性声表面波技术为手段，系统研究磁-电-声表面波非线性耦合机理和柔性声表面波磁传感原理，探索声表面波磁传感器全双工技术思路，提出一套实现全双工柔性无源无线磁传感器的一体化设计方法，为提高我国磁传感器的智能可穿戴水平提供理论和技术支撑。

可穿戴设备是物联网的最新应用，前景广阔。柔性传感器是可穿戴设备的核心。作为传感技术应用最广泛的磁传感器，柔性化研究极少。柔性无源无线传感器同时具备传感、柔性、无源和无线功能，完全满足可穿戴无线传感器网络的要求，是可穿戴传感技术发展的重要趋势。本项目创新提出融合磁电换能和声表面波技术的柔性无源无线磁传感器，同时实现一体化设计和全双工通信，根本解决声表面波传感器的无线通信距离瓶颈，为提高我国磁传感器的智能可穿戴水平提供理论和技术支撑。本项目研究柔性磁电换能器的非线性理论及特性，研究柔性声表面波器件理论及特性，研究柔性声表面波磁传感技术，研究柔性声表面波磁传感器的“全双工”无线通信技术，研究全双工柔性无源无线磁传感器一体化设计及应用。重要研究结果包括：(1)建立了磁致伸缩相的非线性理论模型，建立了柔性磁电换能器的非线性理论模型，完成了磁电换能器的柔性化设计和制备，成功搭建测试平台，通过制备、表征，获得最佳材料和工艺参数；提出了基于FeSiB/PVDF的柔性磁电层合结构，其共振磁电电压系数可达240.42 V/cmOe。(2)建立了柔性声表面波器件新型波模式理论模型，设计并优化了柔性声表面波谐振器结构，研究了器件结构和材料参数对声表面波谐振器性能的影响，利用MEMS工艺制备了声表面波谐振器并进行了相应测试，器件性能优良。(3)完成了柔性声表面波磁传感机理研究，建立了静动态响应模型；完成了传感器敏感单元的结构设计和优化；通过对传感器主要噪声来源和特性的分析，建立了相应模型并提出优化方案；通过实物加工测试，传感器性能优良，灵敏度达到80.21kHz/Oe，最小分辨率可达1.25×10-8T。(4)完成了声表面波传感器全双工通信技术的研究并建立模型；研究了人体对可穿戴天线辐射的影响规律，并对柔性天线的结构进行优化设计；完成了一体化结构的柔性无源无线磁传感器设计制作和应用研究。解决了磁传感器的柔性化和无源无线化问题，使得柔性无源无线磁传感器的应用更加便利可靠，将会带来巨大的应用市场。