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关键词： Chipless RFID   convolutional neural networks   1D CNN   complex natural resonances   short-time matrix pencil method  

摘要： This paper proposes a chipless radio frequency identification (RFID) multi-tag detection system. The one-dimensional convolutional neural network (1D CNN) was employed as an intelligent classifier of the proposed system, which was fed by complex natural resonances (CNRs). Experiments with contexts of a single chipless RFID tag were conducted to collect input datasets for training and validating the 1D CNN. The CNRs and natural frequencies only extracted from the individual tag's responses by using the short-time matrix pencil method (STMPM) and then obtained after performing data augmentation were separately fed to the 1D CNN for training and validation in order to compare their performance. The accuracy obtained from the training and validation of the 1D CNN fed by the CNRs was significantly higher than that of the 1D CNN fed by the frequencies only. The performance matrices in terms of precision, recall, and F1-score also confirmed the superiority of the use of CNRs over that of frequencies only. In order to verify the performance of real-time multi-tag detection utilizing the proposed system, experiments with contexts of multiple tags were carried out, and the experimental results have shown that the system using the 1D CNN fed by the frequency only failed to detect multiple tags. In contrast, the proposed system was able to deliver 100% accurate multi-tag detection. However, as demonstrated by the experimental results, the proposed chipless RFID multi-tag detection system was restricted to a resolution of 3 cm.

关键词： 智能注水   数据传送   RFID   井下阅读器   标签捕获器  

摘要： 石油是一种重要的现代能源,也是保障国家安全的基石。油田注水是保持地层压力、提高油气藏采收率的重要措施。随着油田开采进入后期,必须采用分层注水技术,要实现准确的分层注水,就需要地面能够精准地控制和调节不同地层的配水器的开度,因此,必须及时向其传送指令。在目前可行的地面—井下的通讯技术手段中,光纤、电缆等有线传输方式,都存在成本高、施工难度大的问题,对此,本文提出一种基于RFID技术的、低成本的通讯手段,具有非常积极的现实意义。本文的研究内容与阶段性研究成果如下:1.针对投放电子标签可能影响正常注水作业问题,设计了一套自动/半自动的RFID标签地面投放系统,借助地面注入井底的水流,通过操纵阀门的开启和关闭,将存储有配水器开度调节指令信息的电子标签携送至井下目的层段。2.针对在井下密闭井筒的水介质中,难以准确读取电子标签的信息问题,研究了电磁波信号在注水井筒中的传播特性,通过合理的设定系统工作频率,优化井下阅读器和电子标签的天线设计等技术措施,以增强信号的发射强度,减小信号传输过程的衰减幅度,从而提高电子标签信息读取准确率。3.针对电子标签在井筒中无序流动,造成其与井下阅读器距离远、停留时间短的问题,设计了电子标签捕获器,从而可以成功“捕获”地面投放的电子标签,降低电子标签的游动速度,缩短其与井下阅读器的接触距离。4.按照井下环境要求,设计了井下电子标签阅读器的电路模块和配套软件,自制了一种小尺寸耐水耐压封装的电子标签;编写了地面的电子标签数据写入软件,制成了一套原理样机。测试表明,在100℃的沸水高温环境下,井下阅读器可以正确读取电子标签所携带的指令信息。这些研究成果为实现智能注水系统的地面—井下指令传送提供了一种作业简便的低成本解决方案,具有较高的工程应用价值。

关键词： 无芯片标签   变极化   射频识别   土壤湿度传感  

摘要： 近年,随着传感网络在智能农业、智能制造、智慧城市等物联网场景的广泛应用,无芯片RFID（Radio Frequency Identification）传感器标签作为传感网络的关键组成部分,已成为科研工作者的关注焦点。在智能农业领域,无芯片RFID传感器能够对土壤湿度进行实时监测,减少因湿度异常带来的病害,提高作物产能。无芯片RFID传感器具有成本低廉、无线通信、非视距传输、ID识别的优势,能够很好地解决传统土壤湿度传感器存在的多个传感器信息无法区分、电线裸露会带来危险以及大面积应用成本高昂等问题。然而土壤环境中的环境噪声较空气中更多,无芯片RFID标签的信号易被噪声干扰。为了更准确地识别数据,可以通过变极化特性提高标签的抗干扰能力。因此,研究应用于土壤湿度检测的变极化无芯片RFID传感器标签有着重要意义。 本文主要研究了三款应用于土壤湿度检测的变极化无芯片RFID传感器标签,工作内容如下: （1）小型变极化无芯片RFID土壤湿度传感器标签。利用偶极子的谐振频率受到环境介电常数影响的原理,对于土壤湿度进行传感。为了更好地实现传感与编码功能的区分,该传感器由三组加载矩形贴片的L形谐振器组成,整体尺寸为75×75×1.6 mm3,使用FR-4板材作为介质基板,并在标签外侧覆盖RS-2000材料作为保护层,通过L形谐振器实现变极化特性。该传感器标签实现εr=5–20的土壤湿度检测范围,对应土壤湿度约5%–35%,编码容量为2 bits。最终,对标签进行实物加工并在实际环境中进行了测量。实际测量中该传感器标签的湿度检测范围为4.52%–35.22%,编码容量为2 bits,验证了该传感器标签的湿度传感功能以及编码功能的可行性。 针对上一款土壤传感器在实测中表现出土壤湿度检测范围较窄,仅适用在低湿度的问题,提出一款用于中高湿度的,检测范围更宽的无芯片RFID土壤湿度传感器标签。 （2）基于Z形谐振器的变极化无芯片RFID土壤湿度传感器标签。该传感器由两组Z形谐振器组成,整体尺寸为100×95×1.6 mm3,使用FR-4板材作为介质基板,并在标签外侧覆盖RS-2000材料作为保护层,利用Z形谐振器实现变极化特性。该传感器的湿度检测范围为εr=20–45,对应土壤湿度约35%–70%,编码容量为2 bits。最终,对标签进行实物加工并在实际环境中进行了测量。实际测量中该传感器标签的湿度检测范围为35.22%–70.38%,编码容量为2 bits,验证了该传感器标签湿度传感功能以及编码功能的可行性。 由于前两款土壤传感器在仿真和实测中都只能得到2 bits的编码容量,为了实现更高的编码容量,提出一款加载马刺缝隙的变极化无芯片RFID土壤湿度传感器标签。 （3）加载马刺缝隙的变极化无芯片RFID土壤湿度传感器标签。通过在I形谐振器中加载马刺缝隙,得到变极化特性,同时马刺缝隙可等效为一个LC并联谐振回路,通过调节马刺缝隙的长度对谐振频率进行改变,从而实现频移编码,在限制频段内提高编码容量。该传感器由四个加载马刺缝隙的I形谐振器组成,整体尺寸为85×85×1.6 mm3,使用FR-4板材作为介质基板,并在标签外侧覆盖RS-2000材料作为保护层。该传感器的湿度检测范围为εr=20–45,对应土壤湿度约35%–70%,编码容量为5 bits。最终,对标签进行实物加工并在实际环境中进行了测量。实际测量中该传感器标签的湿度检测范围为35.22%–70.38%,编码容量为5 bits,验证了该传感器标签湿度传感功能以及编码功能的可行性。 本文将变极化技术与马刺缝隙应用于无芯片RFID土壤湿度传感器标签设计中,并给出了相应的设计指导,为应用于土壤湿度检测的无芯片RFID传感器的实现提供了参考。

关键词： UHF RFID   阅读器数字基带   SoC   FPGA原型机   自适应电压控制  

摘要： 随着网络技术的发展,网络连接由有线连接逐渐转向无线连接,网络接入设备也由电脑、服务器等复杂网络设备不断向下延伸,由互联网转向了物联网。在物联网技术中射频识别技术RFID以其独特的优势在各个领域被广泛应用。 本文设计了一款基于ISO/IEC 18000-6C协议标准的具有专用功能的UHF RFID阅读器SoC系统,设计主要包含UHF RFID阅读器数字基带电路设计和RISC-V SoC系统设计两部分。数字基带电路设计实现了协议在物理层中所要求的PIE编码、CRC校验,FM0/Miller解码模块等;RISC-V SoC系统设计选用蜂鸟E203处理器作为SoC内核,并根据内核外设总线需求和内核结构,完成了外设挂载、中断映射、GPIO复用等修改,最终完成SoC总体设计。基于SMIC 0.18μm CMOS工艺标准单元库,使用DC、ICC等ASIC工具完成了前端综合与后端版图等相关工作,SoC总体消耗器件61048个,版图面积约45.74mm2。在前端设计阶段,为了验证设计可行性,基于Vivado平台和Xilinx ZC706 FPGA开发板实现了FPGA原型机并编写了配套的嵌入式程序,验证了SoC设计的正确性。 为了降低阅读器SoC功耗,本文提出了一种自适应电压调节系统,其基于双影子触发器结构的动态电压监测系统,使用双影子触发器和动态可配置延时链对时序关键路径的工作状态进行监测,通过时序信息动态调节供电电压,降低芯片功耗。参考1.68V供电功耗,RFID基带电路在采用双影法动态电压调整后,可减小33%～78%功耗,增加面积约占SoC面积0.2%。

关键词： RFID原理及应用课程   物联网工程   RFID系统  

摘要： 随着各式各样新兴专业设立，RFID原理及应用课程在许多专业中逐渐开设，物联网工程专业将其列为专业核心课程，其理论性与实践性较强，且学习难度较大。基于课程学习与实践可促使学生充分了解RFID理论，熟练掌握RFID应用技术与方法，可生成相对简单的RFID应用系统。从教学观念、教学实训设备、教学方法、教育资源等方面入手，对RFID原理及应用课程实践改革进行探究，以提升课程教学效果。

关键词： 超高频射频识别技术   无人机技术   RFID感知技术   多环境变量  

摘要： 射频识别(RFID)标签具有无源、体积小、远距离读取等特点,使用RFID标签感知目标物品的状态,在一定程度上可以取代常规的有源传感器。现阶段基于RFID的感知技术均采用单个物理特性变化来感知目标物品的状态,在实际应用中这种感知方式容易受到环境因素等影响。本文研究了基于无人机的RFID移动感知平台多环境变量的感知方法,旨在解决基于RFID的感知技术在现实应用当中受感知距离、角度、测量环境、部署成本与空间要求等多种限制因素的影响。 首先,针对基于RFID的感知技术中单物理特性感知过程易受感知环境影响的问题,本文提出了一种基于RFID标签进行多环境变量感知的方法,通过对标签的多个物理特性信息进行分析和处理,可以实现对目标物品的介电常数和温度等多个环境变量进行监测和感知。其次,针对基于RFID的感知技术在实际应用中受感知环境等限制因素影响的问题,本文结合无人机移动搭载技术与基于RFID的感知技术,设计并搭建了基于无人机的RFID移动感知平台。该平台通过无人机搭载UHF-RFID读写器的方式来对RFID标签进行远距离读取,利用RFID标签的物理特性受标签近场环境影响的特点,来达到感知目标物品状态的目的。测试结果表明,该平台可实现远距离大范围对目标状态进行动态感知。接着,在该平台的基础上,通过设计UHF-RFID驱动板取代UHF-RFID系统中的上位机,克服了将基于RFID的感知技术应用在该平台上的空间和重量要求,同时加入了一些辅助模块来完善移动感知平台的功能和稳定性。测试结果表明,UHFRFID驱动板在满足功能需求的同时,符合无人机的载重和空间要求。最后,在本文提出的多环境变量感知的方法的基础上,以酸奶变质过程和谷仓存储环境为例展开了相关感知研究,并运用在本文设计的基于无人机的RFID移动感知平台上进行感知验证。验证结果表明,在感知误差的允许范围内,该方法能够较为准确的感知目标状态变化。 本文针对传统基于RFID感知技术的局限性问题,设计并搭建了基于无人机的RFID移动感知平台。研究了该平台的硬件部分设计和感知部分方法,实现了该平台的动态远距离感知目标的多个环境变量。结合当下物联网和RFID技术产业的不断发展,基于无人机的RFID移动感知平台具有一定的应用和研究价值。

关键词： Household device   home appliance   Internet of Textile Things (IoTT)   radiofrequency identification   RFID   RFID tag   textile RFID transponder   RFIDtex   textronics   washing machine   clothes iron  

摘要： The use of textronic RFID transponders (RFIDtex tags) offers completely new possibilities in designing household appliances. Their implementations in technologies of washing or ironing textiles are very promising. Specific information on maintaining clothes can be stored in the memory of RFIDtex tags that are permanently bound to the products. This information can be read by washing or ironing devices and then can be used to automatically select the best program or mode of machine operation. Since RFID technology is becoming more and more common, the solution seems simple and ordinary. Nevertheless, there are some barriers that prevent the popularization of such applications. Reliability and efficiency of identification are major concerns, especially near surrounding objects, such as other tags, material composition of textiles, and above all, metal drums of washing machines. The main purpose of the presented work is to propose the communication model in the anti-collision dynamic RFID system, dedicated to use in future intelligent industrial and home washing machines. To develop the elaborated idea, the washing machine demonstrator equipped with read/write RFID devices was designed. Moreover, the RFIDtex transponders according to the authors' conception (restricted under Polish patent, No. PAT.231291) are used in experimental stages. As part of the work, appropriate reading and scanning algorithms were developed to manage multiple data readings from tags inside the drum. Also, measurements were carried out to confirm the identification efficiency in such an Internet of Textile Things (IoTT) system basing on the RFIDtex tags that are placed inside the demonstration washing machine.

关键词： mobile RFID   DFSA   tag loss   tags priority  

摘要： In the mobile Radio Frequency Identification system (RFID), the speed of tag recognition and the quantity of lost tags are the problems to be considered in all applications. In this paper, we proposed a novel tag loss control mechanism called Algorithm Based Priority (ABP) to reduce the label loss rate in the mobile environment. There are two kinds of priorities. To reduce the contention of new and old labels on the channel, the ABP assigns a higher-priority to old tags and assigns the other lower-priority to the new tags. The lower-priority tags cannot be identified until all the tags with higher-priority have been identified. The simulation results show that when the speed of uniform tag arrival is greater than 900 tags per second, the system using ABP starts to lose labels, it is obviously better than the Schoute method. When the speed of tag arrival rate varies from low to high, then to low, the ABP also shows its advantage of low tag loss rate. From the simulation results, ABP has good performance in controlling tag loss.

关键词： Sensors   Monitoring   Radiofrequency identification   Inductance   Surgery   Mathematical models   Real-time systems   Blood pressure monitoring   double-helix antenna   radio frequency identification (RFID)   stretchable strain sensor   wireless power transfer (WPT)  

摘要： This work demonstrates a batteryless, implantable blood-flow sensor with radio frequency identification (RFID) readout. This flexible sensor system was developed specifically for surgical implantation around a blood vessel, without contacting blood to reduce platelet deposition, clotting, and other complications with blood-contacting sensors. A flexible sensor and circuit architecture was adopted to enable a cuff-like form factor for surgical implantation around an artery, vein, or graft without piercing or cutting the vessel. This required the development of a flexible RFID data/power antenna using a split-double helix antenna (DHA), which could be opened and closed, unlike a solenoidal or flat spiral antenna. DHAs with diameter of 3-10 mm were fabricated and characterized on the bench, showing a typical coupling coefficient of 0.007 when placed 5 cm from a reader. Prototype implantable DHA systems were developed to wrap around vessels of 3-8 mm. A flexible pulsation sensor (FPS) was developed from a piezoresistive carbon black-polydimethylsiloxane (PDMS) nanocomposite, which enabled the measurement of vascular distension caused by blood flow. A commercial RFID chip enabled sensor readout to an external transceiver in real time with a sample rate of 12 Hz when immersed in saline test media. Validation experiments on a vascular phantom with simulated stenosis demonstrated a blood-flow rate monitoring from 200 to 400 mL/min with the capacity to distinguish flow changes as low as 10 mL/min.

关键词： Radiofrequency identification   Logistics   Protocols   Costs   Antennas   Three-dimensional displays   Security   RFID tags   autonomous retail  

摘要： Radio-frequency identification (RFID) in the ultra-high-frequency (UHF) band with passive tags was envisioned for logistic purposes to track a large number of tagged items. However, the present designs of hardware and air protocols still fall short of the required functionality to deploy in large autonomous facilities such as retail shops and assembly factories. This paper presents the evidences of the current RFID limitations, and illustrates the possible paths towards future adoption in large-scale logistic applications.