2.45 GHz RFID半有源标签电源管理电路设计

针对半有源标签的特点,分析了制约半有源标签读写距离与使用寿命的因素,提出一种适用于2.45 GHz射频识别的带模式控制功能的电源管理电路设计方案,以使标签的识别距离最大化,延长标签的使用寿命.该方案中,标签可根据与读写器的距离自动切换有源/无源工作模式,供电电源也随之在内部电池和射频信号之间自动切换.在无源模式下,所有高功耗模块,如低噪声放大器、调制器和功率放大器将被关断,以最大程度地节省整体芯片功耗;在有源模式下,高功耗模块启动,标签的工作距离大大提高.仿真结果表明,在输入电压为500 mV,负载电阻为60 kΩ的情况下,电荷泵的输出可达1.9V,为其他模块正常工作提供了可靠保证.     

集成高效率电荷泵的无源电子标签芯片射频前端设计

提出了一种满足ISO/IEC18000-6C标准的无源超高频RFID(射频识别)标签芯片的射频前端结构,该结构包括高效率电荷泵、解调器、调制器、阻抗匹配网络和ESD保护电路。电荷泵通过阈值补偿原理及精确控制补偿电压有效抑制反向漏电流,消除了传统电荷泵中的阈值损失。芯片经TSMC0.18μm CMOS mixed signal工艺流片,实测结果表明,标签最远读距离达7m,写距离为3m,可应用于识别与定位,同时满足HBM2 000V的抗静电指标。     

基于nRF24LE1的有源RFID电子标签的设计简

本文提出了一种基于nRF24LEl射频芯片和RFX2401C功率扩展芯片的有源RFID电子标签的设计,包括硬件电路设计和软件编程设计。该电子标签工作在2．4GHzlSM频段,通过功率扩展芯片RFX2401C提高了标签的发射功率和接收灵敏度,利用接收功率检波（RPD）实现载波监听,解决多标签的碰撞问题,采用无线唤醒技术有效降低了系统的功耗,利用电源监管功能提高工作稳定性。测试结果表明：该标签抗干扰能力强,传输稳定,工作距离远且可调。     

低功耗射频触发唤醒电路设计

为解决目前有源RFID标签的能耗问题,提出了基于射频触发唤醒技术(Radio wake-up)的低功耗解决方案。在传统有源RFID标签的基础上增加射频唤醒电路,阅读器首先发送一个唤醒信号,将附近的标签从休眠状态唤醒,然后进行数据通信。这使得有源标签大部分时间均处于低功耗的休眠状态,该方式可大幅减少射频通信模块的功耗,延长有源标签的寿命。仿真结果表明,该电路在-45.2 dBm输入功率下可唤醒标签,唤醒距离为30 m,且唤醒电路的功耗仅为4.11 μW(3 V,1.37 μA),能够满足大部分应用需求。     

利用实时频谱分析仪发现UHF频段RFID信号一例

RFID是一种射频识别技术，是通过射频技术生成以及采集特定代码信息的过程。RFID的主要工作频段有两个，HF段和UHF段，UHF频段在国际上各国一般取860～960MHz频段的子集，设备采用反向散射的方式工作，标签利用接收到的由读写器发出的射频能量，将其中的编码信息利用电波传播回去，其工作距离较大，一般最大可达3～10米。目前860MHz～960 MHz RFID系统的读写设备通常采用跳频工作模式，在一定的工作频带下划分多个跳频信道，按特定跳频顺序输出射频能量进行工作。在实际的工作过程中，读写设备输出调制波或者连续单载波，调制波所携带的信息是为了对标签进行各种操作，而连续单载波是为了向标签提供能量。     

基于BLF时钟的RFID低功耗数字基带设计

提出了一种符合ISO/IEC 18000-6C协议中关于时序规定的射频识别(RFID)无源标签芯片低功耗数字基带处理器的设计.基于采用模拟前端反向散射链路频率(BLF)时钟的方案,将BLF的二倍频设置为基带中的全局时钟,构建BLF和基带数据处理速率之间的联系;同时在设计中采用门控时钟和行波计数器代替传统计数器等低功耗策略.芯片经TSMC 0.18 μmCMOS混合信号工艺流片,实测结果表明,采用该设计的标签最远识别距离为7 m,数字基带动态功耗明显降低,且更加符合RFID协议的要求.     

用于125kHz RFID标签芯片的低功耗射频模拟接口

设计了一种用于125 kHz射频识别(RFID)标签芯片的射频模拟接口。通过在NMOSFET栅交叉型整流电路中加入过压保护电路,可在5 ms内将整流电压稳定在6.5 V,发送数据期间自动切断静态电流回路,解决了整流电路额外损耗能量的问题;数据收发采用接收幅移键控(ASK)信号、发送频移键控(FSK)信号的模式,提高了标签芯片的有效读写距离;为解决FSK频率不准导致的误码问题,在电路内部预留了调频(FM)端口,实现了芯片的FSK谐振频率精准可控。仿真结果表明,芯片完成一次读写操作供电电压下降50%,整体功耗342μW,可将数据1和0分别转换成频率为123.5 kHz和136.9 kHz的FSK信号。基于SMIC 0.35μm EEPROM工艺进行了流片验证,模拟电路版图面积为0.34 mm²,测试结果表明,芯片可解调125 kHz ASK载波信号,可将数据识别码准确无误地发送给读写器,最长读写距离为9 cm。其低功耗、远距离读写的特性非常适合用于植入式动物标签。     

基于FPGA的RFID板级标签设计与实现

在分析射频识别原理和特点的基础上,讨论超高频射频识别系统中电子标签设计技术,并采用EP1C6Q240FPGA对超高频电子标签进行了板级设计及其实现.利用Verilog语言实现了标签数字电路,并在板级标签中进行了验证.测试结果表明,该设计实现了ISO18000-6C标准的标签读写功能,读写性能优异,为下一步设计出符合该标准的电子标签芯片提供了有力保证.     

2.45GHz电子射频标签模拟前端芯片的研制

分析了RFID系统的组成和基本原理,针对超高频EPC C1G2协议,提出半无源及有源电子标签前端结构及参考电路,包括整流器、偏置单元、上电复位、解调、反向散射调制、振荡器等部分.采用多种方法,极大程度上实现了电路整体的低功耗,并且采取了限幅、ESD电路,保障了电路的稳定性.采用标准CMOS工艺,设计出了低功耗、低电压工作的2.45 GHz射频模拟前端芯片电路,芯片在0.8～1.8 V电压内均可正常工作.芯片的静态工作电流为2μA,芯片工作时,平均工作电流约为65μA.     

用于定位的低功耗有源RFID标签的设计

本文从有源标签的设计理念出发,针对一般小范围空间RFID定位的需求,根据低功耗、高效率的原则进行RFID标签的设计。系统在硬件上采用了MSP430F2012单片机和nRF24L01射频芯片的低功耗组合;软件上则结合了RFID定位的特点,介绍了有别于一般以识别为主要目的的标签的设计方法,并分析了其软件设计流程以及简单的防冲突能力。通过良好匹配的天线,本设计有效读取距离可达几十米,足以应付一般空间内定位的需求。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.