基于声表面波的TATP传感器设计

三过氧化三丙酮(TATP)是一种新型的液体炸药。由于TATP分子中不含硝基,传统的一些基于硝基特征检测的技术无法对其进行有效识别检测;而现有针对TATP的检测技术存在预处理繁琐,检测时间长,灵敏度低及需要特殊设备等缺陷,无法满足现场实时、快速检测的需要。该文提出了一种基于声表面波(SAW)技术、针对TATP检测的新型传感器,将高分子材料技术与SAW技术相结合,分别利用新型树枝状高分子敏感材料的高灵敏度和选择性,与SAW传感器高质量敏感性的优点,对TATP进行快速、可靠检测,从而为实现快速防护做好准备。结果表明,该传感器检测阈值最低可达0.5×10^-6,响应速度可达到秒级。     

基于WSN的智能条形码识别系统

为了实现现代大型仓储、物流、超市对条码扫描设备的无线、长通信距离的要求,设计了一种基于无线传感器网络的智能条形码识别系统。该系统采用CC2430芯片为主要通信芯片,应用基于无线传感器网络操作系统TinyOS的CTP协议,从而有效地增加了通信距离。智能化的工作界面由C#编程语言编写,实现了商品的出库、入库、查询、智能提醒等功能。     

一种用于超高频无源标签芯片的整流器设计

基于TSMC 0.18 μm CMOS工艺,提出了一种适用于无源UHF RFID标签芯片的CMOS整流器。与传统二极管连接方式的MOS管相比,使用了一种不同的二极管连接方式的MOS管,减小了阈值电压和漏电流。利用新结构实现了一个5级电荷泵整流电路。测试结果表明,当输入0 dBm信号时,整流器的转换效率为29.24%。整体芯片的面积是(0.7 × 0.6) mm²。     

关于实时物流监控系统设计技术探讨

分析了现有的基于RFID技术的物流监测系统存在的不足,综合无线传感器网络技术与RFID技术的优点,提出了一种全新的基于无线传感器网络与RFID的新型实时物流检测系统。阐述了系统的组成结构和工作原理,并详细介绍了系统的软硬件设计与实现。该系统适用性较高,对于运输重要物资或危险品的车辆,能够实现对物资信息和车辆上重要数据的实时监测、校准、记录和传输等功能。     

基于延迟线理论的无源声表面波气体传感器

针对单输入、单输出及双输入、双输出换能器构成的声表面波(SAW)气体传感器存在的缺陷,研究一种无线无源、温度可测的气体传感器。基于声表面波的延迟线理论,利用叉指换能器的转换能量原理,对叉指换能器及反射器进行合理布局,并使3个反射器之间互为参考反射器,获得一种新型的声表面波气体传感器。该设计减少了传感器中信号间及环境温度等因素对测量的干扰,提高了传感器的灵敏度和测量准确度。该传感器具有结构简单、无线无源等特点,适合在不宜接触的复杂工程环境下工作。     

基于标准CMOS工艺的片上太阳敏感器研究

微纳卫星对于载荷的苛刻要求使得太阳敏感器的微型化研究具有重要意义。为了解决光学器件和处理电路的集成兼容问题,文章基于标准CMOS工艺提出一种新型片上太阳敏感器,以金属走线层构建微型墙结构,两侧均匀分布pn结构成光电传感器,通过检测两侧光电流比例解算出入射光角度。文章从工艺实现、模型建立、数值仿真和实验测试等方面验证了器件的合理性和可行性。最终,片上太阳敏感器阵列芯片质量为1.5g,尺寸为304.2mm³,检测精度为±1.6°,视场范围为80°,可满足微型化需求。     

基于无线HART协议的可燃气体报警仪设计

为解决工业现场可靠监控可燃性气体的问题,提出一种基于WirelessHART协议设计的可燃气体报警仪,对可燃性气体实现监测并实时响应。该报警仪采用MSP430芯片作为主控芯片,通过多种功耗模式实现报警仪的低功耗运行,利用被动检测法使传感器快速检测出可燃气体,并采用WirelessHART协议将数据发送至无线HART网关,实现控制终端与现场设备的双向无线通信。通过实验测试,表明该设计可快速检测出可燃性气体并实现数据的可靠无线传输。     

射频识别芯片设计中时钟树功耗的优化与实现

UHF RFID是一款超高频射频识别标签芯片,该芯片采用无源供电方式,对于无源标签而言,工作距离是一个非常重要的指标,这个工作距离与芯片灵敏度有关,而灵敏度又要求功耗要低,因此低功耗设计成为RFID芯片研发过程中的主要突破点。在RFID芯片中的功耗主要有模拟射频前端电路,存储器,数字逻辑三部分,而在数字逻辑电路中时钟树上的功耗会占逻辑功耗不小的部分。本文着重从降低数字逻辑时钟树功耗方面阐述了一款基于ISO18000-6Type C协议的UHF RFID标签基带处理器的的优化和实现。     

混凝土中钢筋腐蚀监测无线传感器节点的设计

本文提出一种混凝土结构中钢筋腐蚀监测无线传感器节点的设计方案,该节点主要由埋入式传感器和外部电路组成。埋入式传感器基于LC振荡电路,通过不同粗细钢丝的通断情况,使谐振频率发生变化,从而判断钢筋的腐蚀情况,该模块具有电路结构简单,成本低廉,无线,无源,便于工程安装实现等特点。外部电路以MSP430F149为主处理芯片,由DDS、无线数据收发芯片NtLF905等电路实现,该电路能够实时采集埋入式传感器的谐振频率变化信息,并具有通讯距离远、数据传输稳定等特点。     

无源无线声表面波压力传感器研究

无源无线传感器可对快速移动或旋转等环境下的物体进行参数测量,具有无源无线等优势。为此,采用声表面波(SAW)技术和无线射频技术研究实现了一种结构简单的无源无线声表面压力传感器。基于CC1101无线射频模块实现对SAW压力传感器感知信息的无线接收。推导出CC1101射频收发模块的阻抗匹配网络的传递函数,通过MATLAB和Multism软件进行分析和仿真,确定了匹配网络的元件参数,使射频模块工作频率可调;设计并实现了传感器样机。试验结果表明,该无源无线SAW压力传感器具有精度高,稳定性好的特点,为其工程化提供了依据。     

适用于RFID标签及无线传感器的射频唤醒电路

有效的功耗管理是提升有源RFID标签以及无线传感器节点电池使用寿命的重要方法,一种无源射频唤醒电路可以用来控制标签以及传感器节点的工作状态,使之在外界无线电波控制下进行唤醒状态与休眠状态的切换,与传统周期性唤醒方法相比,该方法减少了大量能量损耗.围绕着提高射频唤醒电路灵敏度的指标,对阻抗匹配网络以及整流电路进行了优化.仿真和测试结果表明该电路在-27.7dBm输入功率下可以产生220mV直流输出.该唤醒电路本身无需耗电,实践表明将其应用在RFID标签及无线传感器节点设计中可显著提升电池使用寿命.     

Passive wake-up radios: From devices to applications

Energy efficiency is one of the most important criteria in the design of a wireless sensor network. Sensor nodes are usually battery-powered and thus have very limited lifetime. In this paper, we introduce a novel passive wake-up radio device named WISP-Mote that uses a passive RFID tag as a wake-up receiver for a traditional sensor node. We characterize the WISP-Mote with field tests in different operating environments and present the wake-up probabilities based on the distance between the wake-up transmitter and receiver. We then perform simulations to compare the performance of a network with WISP-Motes and with duty-cycling of the sensor nodes, using the wake-up probabilities measured in our field tests. Additionally, potential applications that can benefit from WISP-Motes are discussed, and the advantages of using WISP-Motes are identified by simulation results based on these application scenarios. Results show that the wake-up radio sensor networks have great potential over duty-cycling approaches for energy efficiency, while providing similar latency and packet delivery performances.     

Metamaterial-inspired passive chipless radio-frequency identification and wireless sensing

The presented paper demonstrates how metamaterials with their unique properties and structures derived from metamaterials can offer solutions to overcome technical limitations of passive and chipless wireless sensor and RFID concepts. Basically, the metamaterial approach allows for miniaturization, higher sensitivity, and an extreme geometric flexibility. Miniaturization is certainly important for both, sensing and identification, while higher sensitivity is primarily applicable to sensors. The geometric flexibility is at first important for sensing since it allows for novel sensor concepts. But at least concerning buildup technology, also RFID concepts can benefit from this advantage. The presented examples of metamaterial-inspired passive chipless RFID and wireless sensing can be assigned to the following three categories: metamaterial resonator approaches, composite right/left-handed lines, and frequency-selective surfaces. In this paper, these different concepts are evaluated and discussed with regard to the metamaterial properties. Furthermore, criteria and figures of merit are given, which allow for a fair comparison of passive, chipless concepts and beyond. Finally, these criteria are applied to the presented sensor and identification concepts.     

A practical quadratic residues based scheme for authentication and privacy in mobile RFID systems

In this paper we propose a novel approach to authentication and privacy in mobile RFID systems based on quadratic residues and in conformance to EPC Class-1 Gen-2 specifications. Recently, Chen et al. (2008) [10] and Yeh et al. (2011) [11] have both proposed authentication schemes for RFID systems based on quadratic residues. However, these schemes are not suitable for implementation on low-cost passive RFID tags as they require the implementation of hash functions on the tags. Consequently, both of these current methods do not conform to the EPC Class-1 Gen-2 standard for passive RFID tags which from a security perspective requires tags to only implement cyclic redundancy checks (CRC) and pseudo-random number generators (PRNG) leaving about 2.5k–5k gates available for any other security operations. Further, due to secure channel assumptions both schemes are not suited for mobile/wireless reader applications. We present the collaborative authentication scheme suitable for mobile/wireless reader RFID systems where the security of the server–reader channel cannot be guaranteed. Our schemes achieves authentication of the tag, reader and back-end server in the RFID system and protects the privacy of the communication without the need for tags to implement expensive hash functions. Our scheme is the first quadratic residues based scheme to achieve compliance to EPC Class-1 Gen-2 specifications. Through detailed security analysis we show that the collaborative authentication scheme achieves the required security properties of tag anonymity, reader anonymity, reader privacy, tag untraceability and forward secrecy. In addition, it is resistant to replay, impersonation and desynchronisation attacks. We also show through strand space analysis that the proposed approach achieves the required properties of agreement, originality and secrecy between the tag and the server.     

Nano Watt CMOS temperature sensor

In this paper, an ultra-low power embedded full CMOS temperature sensor based on sub-threshold MOS operation is designed in a 0.18 μm CMOS technology. It focuses on temperature measurement using the difference between the gate-source voltages of transistors operated in sub-threshold region that is proportional to absolute temperature. By using the proposed scheme the wide range supply voltage of 0.6–2.5 V with inaccuracy of +0.55 °C/V and total power consumption of merely 7 nW at 120 °C is achieved. The performance of the sensor is highly linear and the predicted temperature error is ±2 °C in the range of 10–120 °C. The sensor occupies a small area of 67 × 31 μm². Ultra-low power consumption of the sensor illustrates proper operation for low power applications such as battery powered portable devices, passive RFID tags and wireless sensor network applications.     

阻抗型无线无源声表面波传感器的研究

介绍了一种新型的阻抗负载型无线无源传感器,该传感器由声表面波器件与作为负载的外接传感器构成,采用声表面波器件进行信号传输。在工作时,外接传感器阻抗值的变化使声表面波器件反射回波特性也得到改变,通过检测该回波特性的变化,实现无线无源传感。基于耦合模模型的分析方法,得出了其级联P矩阵形式。针对电阻型和电容型两种不同类型的负载,分别对传感器进行了仿真分析和实际测试。试验结果表明,当电容型传感器作为负载时,可以以相位作为探测基准。     

On the detection of chipless RFID through signal space representation

paper presents a novel approach to model and represent chipless radio-frequency identification (RFID) frequency signatures. The approach involves the geometrical representation of chipless RFID frequency signatures in a signal space. A small set of orthonormal basis functions is derived using singular value decomposition in order to represent the 2 ^b possible tag signatures of a b-bit chipless tag. Each tag signature is represented as a point in an L-dimensional signal space, and minimum distance detection is used to extract the information bit sequence of the tag. Detection error probability is also examined through analytical derivations and Monte Carlo simulation. A set of 3-bit tags were fabricated to validate the approach. Experimental results show that the new approach is capable of accurately detecting information contained in chipless RFID tags. This approach offers a solid mathematical framework for developing novel detection methods for chipless tags.     

一种基于新型同步算法的脉冲UWB能量检测接收器设计

在RFID和无线传感器网络等应用系统中,脉冲UWB(IR-UWB)技术的低功耗和低成本特点具有很大的优势。为了有效地降低功耗和成本,采用了一种基于能量检测,使用开关键控(OOK)调制的IR-UWB接收器,提出了一种使用能量补偿与自适应门限的新型同步与检测算法,此算法降低了接收器的能耗与硬件复杂度。通过对该接收器的仿真及用FPGA硬件实现,表明此算法降低了同步时的功耗及前导序列长度,提高了传输效率,同时保持了系统性能。测试结果表明此接收器架构能够满足在数据率10Mb/s时,功耗仅为1nJ/bit左右,具有低功耗、低复杂度的特点。     

Dual Band RFID-Based Blood Glucose Monitoring System in Wireless Sensor Network Platform

Accurate record on the patient’s glucose information is crucial to assist doctors in decision making and prescribing correct medication. In this paper, a dual band Radio-Frequency Identification (RFID) system embedded with glucose meter was developed by integrating a 920 MHz passive interrogator into the 2.45 GHz active tag to enable automatic patient detection, wireless data recording and monitoring in dense hospital environment with frequent usage. The real-time experimental results indicate that the developed embedded RFID system in the multihop wireless sensor network is able to maintain the integrity of the glucose data according to the identification of the patient until the data are successfully recorded to the remote host system. Design of Experiment method is performed to determine the factors that influenced the throughput performance of the system. Comparisons made between existing non-embedded RFID system and the proposed embedded RFID system. The three factors investigated were the packet length, number of hops and type of RFID. The statistical analysis showed that the packet length as the main factor influencing the throughput performance. The results showed that the larger packets increase the throughput, while the number of hops contributes more to the decreasing effect of the throughput compared to the implementation of embedded RFID system.     

基于传感器网络的超级RFID系统

本文综合RF ID和无线传感器网络技术,提出了一种基于传感器网络的超级RF ID系统,介绍了该系统的组成与体系结构,该系统对Savant的新要求。指出RF ID技术与传感器网络融技术的融合可能是一个新的发展趋势。