UHF无源、高效汽车轮胎嵌入式射频感知关键技术研究

Car tire monitoring is an important safety feature in modern vehicles and strongly improves the reliability of tires and tire control systems. As a consequence, a lot of effort is put into the development of advanced tire monitoring sysytem. This expands the possibilities of conventional tire pressure monitoring systems by acquiring additional sensor data such as tire temperature,contact area, slip angle using RF sensing embedded in tire. At present, researches on RF sensing embedded in a car tire are in the initial stage. RF sensing embedded in a car tire is one of the importang fields supported by national industrial policy, and faces a lot of challenges and difficulties. This program will study the key techniques of UHF passive,efficient RF sensing embedded in a car tire,focuses on solving some key scientific problems about improving the sensing distance and realiability of RF sensing embedded in a car tire. Meanwhile,this program will study the characteristics of wave propagation for UHF embedded in a car tire,determine the dielectric properties ofa car tire, and design the antennas for RF sensing embedded in a car tire first. This program will study the efficient RF energy harvesting methods,optimize the clock signal and control strageties of power consumption for RF　sensing module,and improve the sensing distance and realiability of RF　sensing embedded in a car tire. Moreover, this program will verify the effects and rationality of the research achievements, combining the requirement of enterprises, Guizhou Tire Limited Company, for example. Meanwhile, This will push ahead the adjustments and transformation of the enterprises structure, and promote the core competitiveness and the market share of the enterprises.

针对国内外轮胎嵌入式射频感知研究处于起步阶段，既是国家产业政策支持的重要领域之一，又面临许多挑战和困难的现实，本项目将开展UHF无源、高效汽车轮胎嵌入式射频感知关键技术研究，着重解决提高轮胎嵌入式射频感知距离和可靠性的一些关键科学问题。同时，本项目将重点研究UHF轮胎嵌入式射频感知电磁波的传输特性，采用实验测量和仿真验证的方法研究轮胎复介电常数，优化设计合适的轮胎嵌入式射频感知天线；研究高效轮胎嵌入式射频能量获取方法，优化设计射频感知芯片时钟和感知轮胎多要素能耗控制策略，以降低射频感知模块能耗, 提高轮胎嵌入式射频感知距离和可靠性，以提升研究成果的理论和应用价值。同时，结合企业实际应用，验证项目理论成果的合理性、有效性，促进企业结构调整和转型，提升企业的核心竞争力和市场占有率。

针对国内外轮胎嵌入式射频感知，特别是智能轮胎的发展，本项目开展了UHF无源、高效汽车轮胎嵌入式射频感知关键技术研究，主要内容如下：. （1）UHF轮胎嵌入式电磁波传输特性研究。建立了UHF轮胎嵌入式无源射频感知电磁波功率传递模型。数值分析表明，为提高UHF轮胎嵌入式射频感知读取距离和可靠性，读写器天线应采用水平极化方式；合理设计器件嵌入轮胎的深度，避免电磁波功率传递函数处于波谷位置。. （2）设计了一种UHF轮胎嵌入式小型化射频感知弯折天线。利用弯折天线的周期性和紧凑性，设计了一种简单、具有良好阻抗特性和绑定特性的UHF轮胎嵌入式小型化射频感知弯折天线。测试表明：读取距离小于90cm时，识别率大都大于80%；读取距离小于50cm时，识别率大于90%，标签与轮胎具有良好的绑定效果。 . （3）提出了一种小型化低功耗多传感可配置后向散射通信系统。 系统架构通过无线射频能量获取和传感节点的射频唤醒，有效地降低了系统功耗。提出了一种副载波可配置的频分多址接入方法，给出了避免多传感器接入碰撞的传感数据脉冲周期约束条件。实验验证了提出架构的有效性和可行性。. （4）提出一种UHF带限单谐振电小天线射频功率获取和平衡方法。 给出了带限单谐振天线吸收、散射截面积与频率之间的关系，得到了吸收效率上、下界的解析解，研究了吸收功率与其最大值之比、散射功率与其最大值之比、吸收功率与散射功率之比、吸收功率与获取功率之比与谐振频率之间的关系。 . （5）提出无源QAM调制多传感后向散射通信系统功率控制方法。建立了射频能量收集模型，给出了节点工作的能量约束条件。为提高频谱利用率，建立了一种共地无源QAM反向散射通信信号模型，求解了无源QAM反向散射通信功率控制非线性优化问题。解的结果包括在节点工作的能量约束条件下，最大和最小读取间隔，最大和最小占空比。数值计算表明：随着传感器功耗和数量的增加，吞吐量下降。 . 取得的成果可应用于智能轮胎、嵌入式射频感知、以及隐身和反隐身领域。