Analysis and Design of a Quadrature Down-Conversion Mixer for UHF RFID Readers

A quadrature mixer with a shared transconductor stage is analyzed,including voltage conversion gain, linearity, noise figure, and image rejection. The analysis indicates it has better performance than a conventional Gilbert mixer pair in commutating mode. A quadrature down-conversion mixer based on this topology is designed and optimized for an ultra high frequency RFID reader. Operating in the 915MHz ISM band, the presented quadrature mixer measures a conversion gain of 12.5dB,an IIP3 of 10dBm, an IIP2 of 58dBm, and an SSB noise figure of 17.6riB. The chip was fabricated in a 0. 18μm 1P6M RF CMOS process and consumes only 3mA of current from a 1.8V power supply.

Design of low-sidelobe circularly-polarized microstrip array for RFID readers

A low-sidelobe circularly-polarized(CP) microstrip patch array for 2.4 GHz radio frequency identification(RFID) readers is presented.The antenna array with a Chebyshev current distribution is composed of 6 microstrip elements.The CP operation is obtained by the quasi-square patch with difference in lengths of the two sides.The antenna has been investigated numerically and experimentally.Measured results show that the array has a Chebyshev pattern with the sidelobe level of-23 dB, the half-power beamwidth of 16° and an impedance bandwidth(S11≤-10 dB) of 130 MHz, which is suitable for RFID reader applications.

A Single-Chip UHF RFID Reader Transceiver IC

A single-chip UHF RFID reader transceiver IC has been implemented in 0.18 μm SiGe BiCMOS technology. The chip includes all transceiver blocks as RX/TX RF front-end, RX/TX analog baseband, frequency synthesizer and I2C with fully-compliant China 800/900 MHz RFID draft, ISO/IEC 18000-6C protocol and ETSI 302 208-1 local regulation. The normal mode receiver in the presence of -3 dBm self-jammer achieves -75 dBm 1% PER sensitivity. The linear class-A PA integrated in transmitter has 25 dBm OP1 dB output power for CW. The fully-integrated fractional-N fre-quency synthesizer is designed based on MASH 1-1-1 sigma-delta modulator and 1.8 GHz fundamental frequency LC-VCO for lower in-band and out-of-band phase noise. The measured phase noise is up to -106 dBc/Hz@200 kHz and -131 dBc/Hz@1 MHz offset from center frequency and the integrated RMS jitter from 10 kHz to 10 MHz is less than 1.6 pS. The chip dissipates 330 mA from 3.3 V power supply when transmitting 22.4 dBm CW signal and the PAE of linear PA is up to 26%. The chip die area is 16.8 mm2.

基于改进型白鲸算法的RFID网络规划

随着射频识别(Radio Frequency Identification,RFID)技术的发展,人们对其应用的要求越来越高,在阅读器部署方面的研究也逐渐深入。为了解决规定区域内RFID阅读器位置规划问题,在划定的区域内,以标签覆盖率、阅读器间的碰撞干扰、负载均衡为目标来建立数学优化模型,在白鲸算法的基础上提出了一种改进型白鲸算法。首先,针对标准白鲸算法存在易陷入局部最优、丢失次优解的缺陷,提出了一种更新精英群体机制;其次,为了增强算法的探索能力,加入了反向学习策略;最后,运用该算法来解决RFID网络规划问题。通过在一定环境中放置不同数量集群和随机分布的标签,将改进型白鲸算法与粒子群算法、灰狼算法和标准白鲸算法进行对比。仿真结果表明,在相同环境下,改进型白鲸算法的性能相比粒子群算法平均提高了21.1%,比灰狼算法提高了28.5%,比白鲸算法提高了3.3%,说明该算法相比其他3种算法在搜索精度上具有更好的性能,并通过阅读器优化部署测试,验证了该应用的有效性和可行性。

基于FPGA的RFID阅读器研究

RFID(Radio Frequency Identification,射频识别)通过自动识别帮助机器或计算机识别对象,记录元数据或通过无线电波控制单个目标等。当RFID阅读器与Internet终端相连接时,阅读器可以根据需要全局、自动、实时地识别,跟踪和监视带有标签的对象。研究从基于FPGA(Field Programmable Gate Array,现场可编程逻辑门阵列)的RFID阅读器三个方面入手进行阐述:整体、硬件部分和软件部分。首先论述阅读器的整体构成、天线以及数字基带结构,然后从硬件部分和软件部分细致地对阅读器进行剖析阐述,最后进行了仿真模拟。

基于RFID的笼内小鼠定位跟踪系统设计

常见的定位技术用于笼内小鼠跟踪准确度不高。为提高笼内小鼠定位准确性,提出了一种基于射频识别(RFID)技术的笼内小鼠定位跟踪和行为分析系统,通过放置在饲养笼下方的RFID读写器天线阵列板实现定位跟踪,上位机软件可实时显示小鼠的活动轨迹图以便科研人员对小鼠进行行为分析。通过模拟实验和生物实验,该系统可准确定位4×6阵列中小鼠位置,定位准确率可达95%以上,其中,组成阵列的单元格尺寸仅为45 mm×45 mm。

一种热带鱼形端射圆极化RFID阅读器天线

本文提出了一种端射圆极化RFID阅读器天线。该天线采用矩形波导结构(等效为磁偶极子)结合一对热带鱼形振子结构(等效为电偶极子),同时采用约四分之一波长的微带线结构和U型微带线调节阻抗匹配以及移相。最终,设计了一款超高频端射右旋圆极化天线,仿真结果表明该天线在谐振频点处的S11为-29.5 dB,增益Gain为4.49 dBi,阻抗带宽为90 MHz(880 MHz-970 MHz),3 dB轴比带宽(AR)为150 MHz(850 MHz-1000 MHz),可广泛应用于超高频RFID阅读器。

RFID射频读卡器密钥异常变化处理研究

通过研究医疗检测设备仪器中用于体外诊断样本数据追踪功能的RFID读卡器在读样本标签数据时出现读卡失败的情况,对在线射频读卡器硬件组成和软件系统程序逻辑设计,以及读卡器和标签中的密钥存储位置和交互验证过程进行分析,同时对实际读写卡过程中的软件操作方式及读卡器和标签的应答模式进行总结,通过对比编辑器产生的.map文件,查询并验证导致存储区域密钥常量发生修改的根本原因。结果表明,在程序跳转过程中,由于引导程序中定时器中断向量未及时关闭,导致变化的中断运行变量将系统密钥内存常量进行修改,出现密钥验证失败导致读卡数据失败的问题,通过及时关相应中断的方法,解决读卡数据失败的问题,保证诊断检测设备数据追踪的稳定运行。

RFID技术在地铁票卡读写器系统模式优化中的应用

无线射频识别技术(Radio Frequency Identification,RFID)具有无需直接接触即可读取数据的特性,已广泛应用于自动识别和数据捕获系统,特别是地铁票卡系统中。通过使用RFID技术,地铁票卡读写器系统不仅能提高票卡处理速度,还能增强数据的安全性和处理能力。本文深入探讨了基于RFID技术的地铁票卡读写器系统的设计与优化,包括系统需求分析、数据处理、读写识别技术的优化以及整体系统功能的实现,并通过系列系统测试验证了所提出优化措施的有效性。

基于G_NSGA-Ⅱ算法的RFID网络规划

针对RFID网络中阅读器冲突问题,在NSGA-Ⅱ算法的基础上提出G_NSGA-Ⅱ算法。对RFID网络规划问题进行数学建模,引入全局存档机制存储精英解,保留性能最佳个体;采用精英保留策略的锦标赛选择方法,确保选择出的个体具有较优秀的性能;同时,引入高斯变异算子,以增加种群多样性,从而避免算法陷入局部最优解。仿真结果表明,G_NSGA-Ⅱ算法所产生的解集质量较好,相较于NSGA-Ⅱ、AW_GA和MOEA/D等3种算法,其在解集的分布性和收敛性上具备明显优势,在解决RFID问题上具备有效性和可行性。

物联网中基于多reader合作机制的RFID-sensor信息收集协议

为有效收集多reader环境下传感器节点的信息,提出了一种高效率的数据收集协议-MRCIC。MRCIC通过前次信息收集的时槽位置来分配本次tag回复信息的时槽位置,缩短了检测区域范围内tag的时间。针对于reader冲突导致的无法检测到多reader相交区域内tag问题,MRCIC采用没有相交区域的多个reader同时发送询问信息,其他reader睡眠的方法来收集相交区域范围内tag信息,提高了信息收集的准确率。理论分析与实验结果表明,MRCIC比AMDCU、ALOHA、BT和PIC延迟更短,准确率更高。

Design and analysis of a highly-integrated CMOS power amplifier for RFID readers

To implement a fully-integrated on-chip CMOS power amplifier（PA） for RFID readers,the resonant frequency of each matching network is derived in detail.The highlight of the design is the adoption of a bonding wire as the output-stage inductor.Compared with the on-chip inductors in a CMOS process,the merit of the bondwire inductor is its high quality factor,leading to a higher output power and efficiency.The disadvantage of the bondwire inductor is that it is hard to control.A highly integrated class-E PA is implemented with 0.18-μm CMOS process.It can provide a maximum output power of 20 dBm and a 1 dB output power of 14.5 dBm.The maximum power-added efficiency（PAE） is 32.1%.Also,the spectral performance of the PA is analyzed for the specified RFID protocol.

基于RFID系统的Reader-Tag安全协议的设计及分析

国内外开展了很多加强RFID安全隐私保护的研究,并提出了一系列的方法,如Hash锁、随机Hash锁和Hash链,但这些方法都有一定的缺陷。针对现有方法的不足,并结合现有的方法,设计并分析了一种新的基于RFID系统的Reader-Tag的安全协议。

标签不均匀分布场景中的RFID标签防碰撞方法

为解决标签不均匀场景的标签丢失问题,提出了一种可以应用在标签不均匀分布场景的基于排队论的标签漏读预警RFID防碰撞方法。该方法估算抵达阅读器识别区域内的标签数,通过分析标签的抵达率和阅读器的平均服务率,判断系统是否稳定。当系统不稳定时,通过提示使用者停止运动,减少标签丢失现象的发生。仿真实验的结果显示,该方法在标签不均匀分布的场景中有效地减少了标签丢失,提高了系统性能。

A 900 MHz,21 dBm CMOS linear power amplifier with 35% PAE for RFID readers

A two-stage differential linear power amplifier （PA） fabricated by 0.18 μm CMOS technology is presented. An output matching and harmonic termination network is exploited to enhance the output power, efficiency and harmonic performance. Measurements show that the designed PA reaches a saturated power of 21.1 dBm and the peak power added efficiency （PAE） is 35.4%, the power gain is 23.3 dB from a power supply of 1.8 V and the harmonics are well controlled. The total area with ESD protected PAD is 1.2 × 0.55 mm2. System measurements also show that this power amplifier meets the design specifications and can be applied for RFID reader.

A fully integrated UHF RFID reader SoC for handheld applications in the 0.18 μm CMOS process

A low cost fully integrated single-chip UHF radio frequency identification（RFID） reader SoC for short distance handheld applications is presented.The SoC integrates all building blocks—including an RF transceiver,a PLL frequency synthesizer,a digital baseband and an MCU—in a 0.18μm CMOS process.A high-linearity RX frontend is designed to handle the large self-interferer.A class-E power amplifier with high power efficiency is also integrated to fulfill the function of a UHF passive RFID reader.The measured maximum output power of the transmitter is 20.28 dBm and the measured receiver sensitivity is-60 dBm.The digital baseband including MCU core consumes 3.91 mW with a clock of 10 MHz and the analog part including power amplifier consumes 368.4 mW.The chip has a die area of 5.1×3.8 mm^2 including pads.

耦合馈电小型圆极化高增益RFID阅读器天线

提出一种圆极化高增益超高频射频识别(RFID)阅读器天线.天线为微带结构,由分别印制在上下两层介质基板上的辐射贴片、L形馈电结构、接地面、4个短路加载小贴片等组成.采用在辐射贴片中心蚀刻十字形槽,L形结构耦合馈电,在天线四角加载短路小贴片等方法,实现天线的圆极化和高增益.天线总尺寸(L×W×H)为160 mm×160 mm×21.6 mm,实测S_(11)≤-10 dB的频率覆盖范围为896~993 MHz,轴比小于3 dB的频率覆盖范围为902~940 MHz,覆盖频段内最大增益8.5 dBi.所设计的天线易加工、成本低、圆极化、增益高,可应用于各种RFID系统的测试环境中.

A low cost integrated transceiver for mobile UHF passive RFID reader applications

A low cost integrated transceiver for mobile UHF passive RFID reader applications is implemented in a 0.18μm CMOS process. The transceiver contains an OOK modulator and a power amplifier in the transmitter chain, an IQ direct-down converter, variable-gain amplifiers, channel-select filters and a 10-bit ADC in the receiver chain. The measured output PldB power of the transmitter is 17.6 dBm and the measured receiver sensitivity is -70 dBm. The on-chip integer N synthesizer achieves a frequency resolution of 200 kHz with a phase noise of -104 dBc/Hz at 100 kHz frequency offset and -120.83 dBc/Hz at 1 MHz frequency offset. The transmitter, the receiver and the frequency synthesizer consume 201.34, 25.3 and 54 mW, respectively. The chip has a die area of 4 × 2.5 mm^2 including pads.

有源RFID景区观光车播报系统设计

由于很多景区地理环境复杂,受天气和环境的影响,传统的定位技术无法实现对景点精确定位和精确播报功能。文章利用有源RFID技术优势结合景区的环境特点,开发了景区观光车播报系统。播报系统由有源RFID标签、车载阅读器、手持式阅读器和播报软件组成。系统通过安装在景点的RFID标签与景点进行一一绑定,车载阅读器接收到RFID标签信息后通知播报软件播报对应景点的视频和语音,实现对景点的精确播报、到站提醒等功能,增强了游客的观光体验,提高了景区的现代化管理服务水平。

基于有源RFID的造车零件运输位置追踪方法

为了获取汽车零部件的精确运送位置,提出一种基于有源RFID技术的造车零件运输位置追踪方法。预先增加RFID有源标签信息,建立信息对应表,根据发送与反馈的信号判定报文队列。采用副载波调制方案对数据调节低频信号,抽取回路信号中低频成分的相位进行测距,从而避免在零件标识过程中产生的冲突;对标记进行处理,得到造车零件的运送位置,跟踪生产部件的运输位置。实验结果表明:在小范围与大范围的零件运输位置追踪过程中,该方法追踪偏差较低,满足设计需求。