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关键词： Microstrip antennas  

摘要： Frequency Identification (RFID) technology is one of the simplest forms of wireless communication systems. It is a unique concept that aims at connecting and identifying tagged assets or objects to RFID readers to collect information. This paper presents the design and implementation of a compact dual-band monopole antenna for RFID applications. The proposed design is a microstrip antenna structure composed of two coupled armed meander-lines having 90 between them to achieve circular polarization. The proposed design is mounted on a 1.6 mm thick FR4-epoxy substrate backed by a partial ground plane with the total area of (58 x 80 mm(2)) to ensure compact size of the design. The designed antenna is fed through a 50-ohm transmission line of length 28.5 mm. The antenna is considered dual bands that resonate at 850 MHz and 1.5 GHz and radiates circularly polarized waves with an axial ratio of 1.4. The simulation results using HFSS software showed promising performance with a bandwidth of 141 MHz at centre frequency 850 MHz and 287 MHz at centre frequency 1.5 GHz, respectively. The S11 parameter shows return loss of -21 dB at 850 MHz band while at the higher frequency band the return loss is much better which was -39 dB. The design provides a perfectly omnidirectional radiation pattern and high radiation efficiency of 93%. Fabrication of the proposed design is done with practical results having a similar trend to the simulated ones to convey good performance of the designed antenna.

关键词： Location awareness   Trajectory   Three-dimensional displays   Robots   Radiofrequency identification   Antennas   Robot kinematics   RFID   phase-based   localization  

摘要： In this paper, a phase and RSSI-based method for indoor localization of UHF RFID tags is proposed and demonstrated. The proposed method exploits the received phase and RSSI profile combined with the location of the moving antenna to locate target tags. The phase and RSSI measurements are collected by a mobile robot carrying a RFID reader and antennas. By analyzing the received RSSI, of which the strength can indicate whether the signal is stable or not, a valid phase profile can be obtained. After obtaining valid phase profile according to the received RSSI, the location of the target along the antenna trajectory is calculated from the stationary point of the phase curve. The location orthogonal to the antenna trajectory distance is estimated by finding the integer number of wavelengths at the point of closest approach which fits the phase profile. 2D localization requires only one straight-line trajectory while 3D localization requires an L-shape trajectory. After estimating the x and y coordinate using the stationary point on each trajectory, the height of the target can be calculated by considering the integer number of wavelengths at the point of the closest approach. A 12 cm 2D localization error and 14 cm 3D localization error are demonstrated.

关键词： Demodulation circuit   RFID   rectifier   Relaxor   temperature sensor  

摘要： Radio frequency identification (RFID) tags are widely used in various electronic devices due to their low cost, simple structure, and convenient data reading. This topic aims to study the key technologies of ultra-high frequency (UHF) RFID tags and high-precision temperature sensors, and how to reduce the power consumption of the temperature sensor and the overall circuits while maintaining minimal loss of performance. Combined with the biomedicine, an innovative high-precision human UHF RFID chip for body temperature monitoring is designed. In this study, a ring oscillator whose output frequency is linearly related to temperature is designed and proposed as a temperature-sensing circuit by innovatively combining auxiliary calibration technology. Then, a binary counter is used to count the pulses, and the temperature is ultimately calculated. This topic designed a relaxation oscillator independent of voltage and current. The various types of resistors were used to offset the temperature deviation. A current mirror array calibration circuit is used to calibrate the process corner deviation of the clock circuit with a self-calibration algorithm. This study mainly contributes to reducing power consumption and improving accuracy. The total power consumption of the RF/analog front-end and temperature sensor is 7.65 mu W. The measurement error of the temperature sensor in the range of 0 to 60 degrees C is less than +/- 0.1%, and the accuracy of the output frequency of the clock circuit is +/- 2.5%.

关键词： 座椅装配   射频识别   准序化   仿真  

摘要： 射频识别(RFID)做为物联网的一项核心技术,具有无接触、远距离实时通信等诸多技术优势,当前已经应用于汽车产业链各个环节,并帮助企业取得了良好的效果。做为传统汽车零部件典型代表之一的汽车座椅行业,如何借助RFID技术提升企业自身的竞争能力,是一个十分有研究意义的课题。本文通过文献研究、调查研究、案例分析等方法对RFID技术在汽车座椅装配环节中的应用进行了研究,并设计了一套可用于座椅装配的RFID应用系统。论文结合当前国内外对于RFID技术的理论研究与在汽车行业应用的实践成果,从汽车座椅装配的现状出发,深入了分析汽车座椅制造行业在JIS交货模式下的生产特点,总结了座椅制造在装配、成品存储、拣货发运等环节所在的问题。针对在传统的以人工扫描条码的方式进行生产管理的模式下,所存在的生产效率低、库存及质量管理水平差、人员成本高、信息系统集成难等问题,结合RFID在座椅装配中的应用分析,提出了基于RFID三个关键技术的系统解决方案。即利用基于RFID标签的工装托盘自动匹配识别技术,构建一套以RFID中间件系统为核心,集成制造执行信息系统与自动化设备控制系统的汽车座椅装配车间RFID装配发运应用系统。结合座椅装配的工艺流程和业务操作,对系统架构与功能进行了详细设计,并通过仿真软件对该系统实施的有效性进行了模拟验证。最后,将该系统在A公司的汽车座椅装配工厂进行了实践应用与实施效果对比分析。结果表明,系统的实施加强了对车间制造过程的生产控制,极大地提升了生产与物流管理的效率,提高了在生产物流与产品交付过程中的质量管理水平,改善了工厂整体的信息化与自动化水平,降低了人工成本,最终增强了企业的整体竞争力。

关键词： 室内定位   惯性导航   射频定位   卡尔曼滤波   BIM航向修正   融合定位算法  

摘要： 随着社会经济的飞速发展,各类大型室内建筑越来越多,人们在室内停留的的时间也越来越长。出于智能化和信息化的要求,人们对于建筑物室内实现导航功能的需求愈发强烈。除此之外,室内位置服务更有广阔的应用前景,例如在火场救援、抗震救灾等复杂环境中,常需要救援人员进入建筑物中完成救援任务。目前基于室内位置服务的技术方案主要有WIFI、低功耗蓝牙(Blue Tooth of Low Energy)、射频标签(RFID)、Zi Bee、超宽带(Ulta Wide Band)、地磁场、惯性导航、计算机视觉和超声波等。众多学者提出了将两种甚至三种定位技术进行组合的定位算法,提高了定位精度和系统冗余度。本文在考虑火场救援等特殊条件的基础上,将基于MEMS的惯性导航技术和无线射频技术进行融合,辅以卡尔曼滤波算法、零速检测算法和基于BIM的航向修正算法,实现火场环境人员定位,主要内容和结论如下:(1)MEMS的捷联式导航系统(SINS)可实现在无任何外部辅助设备环境下的自主定位,不容易受到环境干扰;RFID定位技术可实现非接触状态下的信息交互,定位人员只需携带定位标签即可被系统识别,因此选择上述两种定位技术做进一步研究。(2)基于惯性导航技术的基本原理,对基于MEMS的惯性导航元件进行了研究,分析了惯性导航系统数学结算的基本步骤和导航坐标系之间的转换关系,分析了惯性导航技术的系统误差。针对惯性导航设备精度有限的问题,比较了多种修正算法,在传统卡尔曼滤波修正算法基础上,提出了基于多条件判定算法(加速度峰值条件和加速度阈值条件)的零速检测修正算法,该算法可准确判定行人的步态周期。本文将BIM技术应用于修正捷联式导航系统(SINS)的航向漂移误差,提出了基于BIM技术的航向修正算法。利用Revit软件建立建筑的三维BIM模型,将导出的建筑物楼向信息作为参考航向角,可以提高系统解算运动航向角的准确性。(3)基于射频定位技术的基本原理,对射频定位标签和定位基站的基本原理进行了研究。针对采集数据波动较大的问题,本文提出均值滤波算法进行修正,设计了相关实验验证算法的修正结果。分析了定位基站的布设方式对定位精度的影响,随着定位基站数目的增加,定位精度逐渐提高,但是,当达到五个以上定位基站时,定位精度改变不大。最后通过均值滤波修正算法使得采集的数据曲线更加平滑,显著降低了数据波动,提高了定位算法的定位精度。(4)本文提出基于BIM的SINS-RFID融合定位算法,并设计了验证实验。借助MATLAB仿真平台开发了基于BIM的SINS-RFID组合定位算法,利用卡尔曼滤波算法将惯性导航系统和RFID定位技术得到的位置数据进行融合。为验证融合算法的有效性,设计了验证实验,通过比较选择了合适的实验设备并建立实验场地BIM建筑模型,实验采集的数据通过MATLAB仿真平台进行解算。实验结果显示每100m的定位误差为3.35%,证明了组合定位算法具有较好的稳定性和准确性,可以为室内复杂环境中的行人导航定位系统提供良好的技术支持。

关键词： Axial ratio (AR)   circular polarization (CP)   RFID   reader antenna   return loss  

摘要： In this paper, a bi-directional coplanar-waveguide (CPW)-fed antenna with circular polarization (CP) is investigated as a radio frequency identification (RFID) reader antenna. The antenna geometry is square and printed on one side of the FR4 substrate only, which consumes an overall dimension of 60x60 mm(2) with a thickness of 1.5 mm. The simulated and measured parameters of the antenna are in agreement with an impedance bandwidth (S-11<-10 dB) of 40.2% (2.18-3.28 GHz) and ARBW (<3 dB) of 28.3% (2.03-2.7 GHz), respectively. The peak gain of the proposed antenna is 3.17 dBi in both +/- z directions. An Arduino UNO-based open-source microcontroller setup is used for studying this antenna as an RFID reader antenna, along with a wireless module NRF24L01 module at 2.45 GHz with an external antenna (tag). The path loss between the tag and reader antennas is found to increase in the desired band due to interference exists.

摘要： 近年来，随着我国油气业的发展，油气管道建设规模越来越大。不论是对于新建的长输油气管道，还是在役运营的管道，管道运输的安全问题都是重中之重，因此，管道的维抢修也更加重要。工欲善其事，必先利其器。维抢修设备物资库房管理和工器具管理不容忽视。目前，各油气管道公司的维抢修设备物资库房管理和工器具管理存在很多问题，无论质量还是效率都难以满足新形势下的需要。当前，

关键词： Crowdsourcing   global positioning system   Internet of Things   RFID   wearable sensors   wireless sensor network  

摘要： Hajj and Umrah are Muslims' religious pilgrimages to Makkah, Saudi Arabia. Hajj is considered the largest annual gathering in the world. In Islam, every adult is obligated to conduct Hajj and Umrah at least once if he/she is in good health and can afford to do so. Hajj takes place between the 8th and the 13 day of Dhul Hijjah, which is the last month of the Islamic year while Umrah, the minor pilgrimage, could be done any time of the year. In Hajj, pilgrims, also known as Hajjis, travel around 15 km and pilgrims have the choice to do it by foot, bus or by train. The Hajj journey starts from Mina, which is considered the largest tent city in the world because it hosts more than 10,000 fire resistant tents, and includes various religious rituals. Around 3 million Muslims from more than 183 countries make Hajj every year and the Kingdom of Saudi Arabia is working on increasing this number. Since 1989, researchers in various ICT domains have tried leveraging their expertise in solving challenges and issues related to Hajj and Umrah. Although several papers have surveyed efforts using technology in Hajj and Umrah research, none of them was comprehensive. In this paper, I classified research efforts that used information and communication technologies for solving Hajj and Umrah challenges over the past 33 years based on their applications in 10 categories. I also identified more than 30 technologies used by researchers all over the world to address Hajj and Umrah issues and group research efforts based on these technologies for ease of access. Furthermore, open challenges were discussed and new technologies that could be used to address these challenges were proposed.

关键词： 射频识别   防碰撞   探测   自适应   匹配  

摘要： 无线射频识别(Radio Frequency Identification,RFID)是一项利用射频信号的空间耦合来实现自动识别的技术,是公认的二十一世纪最有发展前景的信息技术之一。RFID具有非接触式读写、环境适应强、可重复使用、自动化程度高等优点,被广泛应用于物流盘点、仓库管理、金融支付、跟踪定位等领域。而RFID技术中最关键的问题是多标签识别问题,但由于单个阅读器仅有一个共享的无线通道,当多个标签同时向阅读器发送数据时,就会发生碰撞(Collision),导致阅读器不能够有效地对标签数据进行读取,解决这一问题的方法就是防碰撞算法(Anti-collision Algorithm)。对于防碰撞算法,EPC Global RFID标准化的协议主要是基于两种通用策略,一种是基于ALOHA的随机性防碰撞算法,另一种则是基于二进制树的确定性防碰撞算法,而本文主要针对确定性防碰撞算法进行研究和改进。相关的研究成果如下:(1)对比分析QT算法、A4PQT算法以及GBAQT算法,针对它们存在识别周期较长、吞吐率低等问题。提出了一种基于映射序列码的自适应查询树(Adaptive Query Tree Based on Mapping Sequence Code,MAQT)防碰撞算法。MAQT算法引入前缀探测机制和自适应多叉树机制,只关注最高碰撞位为首的连续三个比特位,根据碰撞位特征自适应地选择分叉方式,并利用前缀探测机制精准确定查询前缀,避免空闲时隙,减少碰撞时隙。仿真结果表明:MAQT算法能够有效减少总时隙数,提高系统识别效率。(2)针对传统的双前缀匹配(DPPS)防碰撞算法中查询指令只能固定携带两个查询前缀的问题。提出一种基于动态前缀匹配的查询树(Query Tree Based on Dynamic Prefix Matching,DMQT)防碰撞算法,DMQT算法增加汉明重前缀确定阶段,采用四叉树方式来确定标签所有可能携带的前缀,从而避免空闲时隙。且使用动态前缀匹配的思路,根据阅读器探测到的信息来动态确定下一查询时隙需要发出的查询前缀数量,进一步减少查询次数,提高算法性能。仿真结果表明:DMQT算法能够有效减少总时隙数,提高系统识别效率。

摘要： 上海复旦微电子集团股份有限公司宣布推出超高频FM13UF系列标签芯片和FM13RD1616系列读写器芯片,具备超可靠、快速数据写入和读取功能,可有效提升标签盘点成功率,显著拓展标签识读距离,高度适用于无源物联网2.0和3.0的应用场景。复旦微电本次推出了UF0051E、UF011E和UF011X三款符合EPC协议的标签芯片,