Empirical Performance of RSSI-Based Monte Carlo Localisation for Active RFID Patient Tracking Systems

The range of potential applications for indoor and campus based personnel localisation has led researchers to create a wide spectrum of different algorithmic approaches and systems. However, the majority of the proposed systems overlook the unique radio environment presented by the human body leading to systematic errors and inaccuracies when deployed in this context. In this paper RSSI-based Monte Carlo Localisation was implemented using commercial 868?MHz off the shelf hardware and empirical data was gathered across a relatively large number of scenarios within a single indoor office environment. This data showed that the body shadowing effect caused by the human body introduced path skew into location estimates. It was also shown that, by using two body-worn nodes in concert, the effect of body shadowing can be mitigated by averaging the estimated position of the two nodes worn on either side of the body.     

一种有源RFID标签的简单功率控制算法

有源电子标签具有传输距离远、数据处理能力较强等特点。因此,远距离RFID系统被用于集装箱扫描和冷链物流等场合。但是有源标签一般以恒定功率工作,会导致电能的不必要消耗。针对该问题,提出一种有源标签的分布式功率控制算法,通过运用matlab对算法进行仿真分析,结果表明该算法能明显降低有源电子标签的功耗从而延长标签使用寿命。所以随着物联网技术的高速发展,该算法具有一定的商业应用价值。     

一种新型的有源标签防碰撞算法

有源射频识别系统被广泛应用在现代物流、人员追踪与定位中。随着标签数增加,防碰撞问题越来越重要,目前有源标签防碰撞算法普遍比较简单,算法效率不高,而有源标签硬件资源丰富也为设计更好算法提供了可能。提出一种防碰撞算法,采用主从读写器包拯救机制和空闲时隙利用机制,并动态控制帧结束和标签接入,调整接入期收集期顺序。通过对归一化吞吐量的研究与仿真表明,这种新的防碰撞协议性能远优于目前已有研究成果。     

一种面向无源RFID的新型高精度温度传感器

针对目前超低功耗温度传感器误差大的问题,运用由精确比例电流源偏置的寄生衬底PNP晶体管,采用0.18 μm混合信号工艺设计了一种可集成于无源RFID标签的新型高精度温度传感器。传感器核心电路产生与绝对温度成正比的电压信号,通过新型开关电容积分器进行放大,并由改进的12位超低功耗逐次逼近模数转换器完成数字量化。仿真结果表明,单次温度转换时间为4.25 ms；在1.8 V工作电压下,平均电流为17.5 μA；在－37 ℃~91 ℃范围内,温度误差为 －0.1 ℃~0.43 ℃。     

On Loss Differentiation for CSMA-Based Dense Wireless Network

In this paper, we propose a novel method to differentiate packet loss based on interference energy and timing relative to desired signal in CSMA-based dense wireless networks. All measurements are conducted locally at transmitters without any additional over-the-air overhead. Our method can estimate PER (packet error rate) due to interference prior to or after the beginning of the desired signal separately, allowing for more efficient MAC(media access control) adaptation design.     

Low-Power CMOS Rectifier Design for RFID Applications

We investigate theoretical and practical aspects of the design of far-field RF power extraction systems consisting of antennas, impedance matching networks and rectifiers. Fundamental physical relationships that link the operating bandwidth and range are related to technology dependent quantities like threshold voltage and parasitic capacitances. This allows us to design efficient planar antennas, coupled resonator impedance matching networks and low-power rectifiers in standard CMOS technologies (0.5-mum and 0.18-mum) and accurately predict their performance. Experimental results from a prototype power extraction system that operates around 950 MHz and integrates these components together are presented. Our measured RF power-up threshold (in 0.18-mum, at 1 muW load) was 6 muWplusmn10%, closely matching the predicted value of 5.2 muW.     

RFID技术与集装箱追踪管理

本文分四部分介绍了RFID在集装箱物流方面的应用。第一部分描述了全球集装箱物流的现状,分析了当今集装箱运输中存在的问题,指出集装箱物流过程的信息化水平是制约集装箱运输发展的瓶颈之一;第二部分重点介绍了集装箱运输的安全问题以及国内外对此采取的相关的措施,说明了国际贸易便利与安全对RFID技术的需求;第三部分详细阐述了国内外对集装箱RFID技术的研究进展及其产品在集装箱运输中的应用情况;最后通过介绍国外RFID技术在集装箱运输中的应用情况展望了RFID技术在集装箱管理应用中的发展前景。     

有源网络的分割—重建方法及其应用

本文提出了一种有源网络的分割——重建技术:将一个有源网络分割为集总元件子网络和器件子网络,依据各子网络的不定散射矩阵,通过浮地端口的对接与封禁,建立起原网络的散射矩阵,借以完成原网络的分析与设计。利用本方法能处理具有任意复杂拓扑结构的有源电路。文中列举了几个应用实例。     

Phase-Encoded Chipless RFID Transponder for Large-Scale Low-Cost Applications

A novel 3 b chipless RFID transponder is presented. The transponder comprises three microstrip patch antennas, which are loaded with open circuited (O/C) high impedance stubs. The antennas are resonant at nearby frequencies, and when excited with their respective resonant frequency signals, they re-radiate backscattered signals with distinct phase characteristics. This phase information is encoded as hexadecimal bits for the proposed chipless RFID tag. Both the CST Microwave Studio full-wave solver and the anechoic chamber measurements show a 30$^{circ}$ phase step for the 3 b chipless RFID transponder. It it easily transferred to printed technology, and it may find applications in the mass identification market.      

射频识别技术及其应用

首先对射频识别系统的组成和工作原理进行了简单的介绍，然后对射频识别技术的应用进行了简单的分析，提出了射频识别技术所面临的问题，最后对其市场前景进行了预测。     

EPC标准以及RFID的应用

RFID泛社会化应用的浪潮席卷日本,日本的各个有关政府省厅对RFID的应用都做出了明确的规划和目标并指导企业进行了大量实验。在日本RFID领域中大有推广EPC的势头。本文介绍了欧姆龙公司如何与世界同步大力开发RFID技术产品和怎样广泛开展应用的。     

改进型动态时隙冲突跟踪树标签防碰撞算法

射频识别RFID(Radio Frequency Identification)系统内的读卡器在识别大数量标签时常因信号的碰撞而导致系统识别效率降低.动态时隙冲突跟踪树算法DSCTTA(Dynamic Slots Collision Tracking Tree Algorithm)采用动态时隙应答机制可减少前缀开销和迭代开销,但会产生大量空闲时隙.本文将DSCTTA和比特转换方式(BCM)相结合,得到改进型动态时隙冲突跟踪树标签防碰撞算法(IDSCTTA)以防止标签冲突,加快标签识别速度.理论分析及仿真结果表明,IDSCTTA不仅具有DSCTTA的全部优点,而且能够有效地减小识别时延和提高时隙效率,并且标签数目越大,算法性能越优越.     

A Novel Design of Low Power Rectenna for Wireless Sensor and RFID Applications

In this paper, an efficient microstrip rectenna operating on ISM band with high harmonic rejection is presented. By using rotated E-shaped strip in the radiating patch, a new resonance at lower frequencies (2.4 GHz) can be achieved. Also by embedding cutting a rectangular slot with protruded interdigital strip inside the slot in the feed line a frequency band-stop performance can be achieved. The proposed structure has a major advantage in high harmonic rejection. The rectenna with integrated monopole antenna can eliminate the need for an low pass filter placed between the antenna and the diode as well as produce higher output power, with maximum conversion efficiency of 74 % using a 1 K \(\Omega \) load resistor at a power density of \(0.3\,\hbox {mW/cm}^{2}\) .     

用于UHF RFID的高线性度LNA的设计

设计了一种用于UHF RFID读写器芯片的无电感低噪声放大器.该电路具有单端输入、差分输出的功能,噪声电压在差分输出端相位相同、幅度相等,噪声相互抵消;同时,使非线性项系数为0,提高了线性度.采用TSMC 0.18 μm CMOS RF工艺流片,测得在915 MHz下噪声系数小于3.2 dB,1dB压缩点为-7 dBm,IIP3为3 dBm,S11为-12.8 dB,面积为0.036 mm2,功耗小于10 mW.     

Design of a RFID System for Real-Time Tracking of Laboratory Animals

In this paper, a real-time RFID system capable of tracking laboratory animals is designed and implemented. Four passive RFID tags based on low frequency are designed and implemented. The tags can be read by any RFID reader that operates on the low frequency range 125–134 kHz. The tags are designed through the investigation of various antenna, encoding, modulation, and energy harvesting techniques. The tag receives the electromagnetic signal via the antenna, and converts it to a DC signal that the microcontroller can use to manipulate the electromagnetic signal with the data such that the reader can decode the unique tag identifier. RFID sensors are designed and implemented to collect data from various monitored areas of a semi natural environment. The data is sent to a central data coordinator for pre-processing and middleware for data error checking, display and storage. The RFID system can successfully detect and store movement data in real time. A read range of 14.5 cm is achieved.     

航空领域RFID应用介绍

基于最近航空法规修订准许飞机运载的货品使用被动RFID技术,在2006年航空业采用RFID的增幅将超过一倍.此外,国际货运及运输业将紧随零售、消费品的步伐,成为RFID应用的另一热点。随着RFID在航空业内应用标准的相继出台,以及激进的航空公司、机场积极的尝试,RFID在航空业的应用已经初具规模。     

物流信息化推进与RFID应用

本文提出了要提高物流业技术水平,必须推进物流信息化和要推进物流信息化,RFID应用是重要的发展方向的观点。此外,本文还详述了降低物流成本的必要性,先进案例以及推进物流信息化的七项具体工作。最后,本文还介绍了澳港在RFID技术方面的6项合作内容。     

Interoperability Test Methodology for ISO 18000-7 Active RFID

Standards are developed by highly reputed organizations with a genuine intention that the document acts as a reference requirement and specification record for all manufacturers, and in this process the consumer is presented with a list of conforming products that are all interoperable. Active RFID tags and readers are designed with commercial intent by different manufacturers according to the ISO 18000-7 standard. Through intensive research and tests, it has come to our attention that it is possible to design two active RFID systems that in their entirety conform to the ISO 18000-7 standard and yet be not interoperable with each other. From this statement it can be inferred that conformance is not the sufficient condition for interoperability as is popularly believed, but only the necessary or minimum condition to satisfy interoperability. Therefore apart from preliminary conformance testing, it becomes absolutely essential to include additional and supplemental interoperability tests into the verification process of the production cycle. This research primarily establishes the requirement for interoperability testing giving instances where the standard fails to insure interoperable products. The traditional method to test interoperability currently in practice are investigated and their limitations are exposed. Further this research paper introduces an innovative and ingenious methodology to test active RFID systems for interoperability at the physical layer.     

应用于射频前端的高Q值SiGe HBT有源电感

针对传统的共基-共射(CB-CE)回转器有源电感的品质因子Q值低等缺点,应用Cascode结构把CB-CE有源电感改进为共基-共射-共基(CB-CE-CB)有源电感,推导出等效电路及等效阻抗表达式。最后基于Jazz 0.35μm SiGe BiCMOS工艺,利用ADS软件完成电路设计与仿真,应用Cadence Virtuoso平台完成版图设计。改进之后的有源电感,通过改变外加偏置条件,实现了电感值和品质因子Q值的可调,电感值可调范围为0.35～2.72 nH,Q值最大值可达1 172,版图面积仅为51μm×35μm。该有源电感应用于射频电路中,可取代无源电感。与无源电感相比,品质因子Q值明显提高,版图面积大大减小,更利于集成。     

A Weak-Inversion Low-Power Active Mixer for 2.4 GHz ISM Band Applications

This work describes a fully integrated active mixer designed in 0.18 $mu{rm m}$ CMOS technology for 2.4 GHz Industrial, Scientific and Medical (ISM) band applications. The mixer uses a source driven local oscillator (LO) to integrate the RF-LO buffering with the active mixer, and weakly inverted input MOSFETs to improve the gain and noise performance. The double-balanced quadrature mixer has a measured conversion gain of 32 dB with a double sideband (DSB) noise figure (NF) of 8.5 dB at 30 MHz intermediate frequency (IF) while consuming only 0.56 mA of current from a 1.8 V supply.