高频RFID读写器射频模拟前端的实现

射频识别(RFID)系统主要由RFID读写器和RFID电子标签两部分组成.给出了高频(13.56MHz)RFID系统中读写器射频模拟前端的电路设计,符合ISO/IEC14443 type A/type B,ISO/IEC15693和ISO/IEC18000-3中任一个标准的读写器芯片设计均可采用,设计工艺采用了中芯国际0.35μm 2P3M混合CMOS技术,并给出了Cadence环境下的仿真结果.     

小面积低功耗RFID射频前端电路设计

提出了一个适用于EPC Gen2协议的小面积低功耗RFID射频前端电路的设计方案.射频前端电路包括整流器、ASK解调器、ASK和BPSK调制器和传感器模块,射频的工作频率为860～960 MHz.基于具有不挥发存储器和肖特基二极管选项的0.35μm CMOS工艺,设计了RFID射频前端电路.采用开关电容电路技术实现了小面积低功耗RFID射频前端电路.     

小面积低功耗RFID射频前端电路设计

提出了一个适用于EPC Gen2协议的小面积低功耗RFID射频前端电路的设计方案.射频前端电路包括整流器、ASK解调器、ASK和BPSK调制器和传感器模块,射频的工作频率为860～960 MHz.基于具有不挥发存储器和肖特基二极管选项的0.35μm CMOS工艺,设计了RFID射频前端电路.采用开关电容电路技术实现了小面积低功耗RFID射频前端电路.     

基于EPC Class-1 Generation-2标准的RFID阅读器设计

文章设计了基于EPC Class-1 Generation-2标准、工作于UHF频段的RFID(Radio Frequency Identification)阅读器:在介绍RFID阅读器总体架构的基础上,给出了本设计的硬件结构和软件流程;重点阐述了阅读器基带部分信号处理的软件实现和多标签共享信道的防碰撞算法实现.     

超高频RFID标签的数字电路设计

在研究读写器和射频标签通信过程的基础上,结合EPC C1G2协议以及ISO/IEC18000-6协议,采用VHDL语言设计出一种应用于超高频段的射频标签数字电路.对电路的系统结构和模块具体实现方法进行了描述.基于0.18 μm CMOS工艺标准单元库,采用EDA工具对电路进行了前端综合和后端物理实现.给出的仿真结果表明该电路符合协议要求,综合后的电路规模约为11000门,功耗约为35 μW.该电路可应用于超高频段的各种RFID标签的数字部分.     

小面积低功耗RFID射频前端电路设计

提出了一个适用于EPC Gen2协议的小面积低功耗RFID射频前端电路的设计方案. 射频前端电路包括整流器、ASK解调器、ASK和BPSK调制器和传感器模块，射频的工作频率为860～960MHz. 基于具有不挥发存储器和肖特基二极管选项的0.35μm CMOS工艺，设计了RFID射频前端电路. 采用开关电容电路技术实现了小面积低功耗RFID射频前端电路.     

应用于TD-SCDMA/LTE/LTE-Advanced收发机的多频多模CMOS射频接收前端电路设计

设计了应用于TD-SCDMA/LTE/LTE-Advanced收发机中的多频段、多模式射频接收前端电路. 该前端电路采用直接变频结构,包含两个可调谐差分低噪声放大器、一个正交混频器和两个中频放大器。其中,两个独立的可调谐低噪声放大器覆盖了4个射频频段,在较低的功耗下实现足够的增益和噪声性能. 并且利用开关电容阵列来调节低噪声放大器的谐振频率点. 低噪声放大器通过混频器的驱动级跨导晶体管实现结合。正交混频器采用折叠式双平衡吉尔伯特结构,利用PMOS晶体管作为本振信号的开关对,从而降低1/f噪声. 前端电路具有3种增益模式以获得更大的动态范围. 模式配置和频段选择功能都由片上的SPI模块控制. 该射频前端电路采用TSMC0.18um RF CMOS工艺实现,芯片面积为1.3 mm2. 全部频段上测量的转换增益高于43dB,双边带噪声系数低于3.5dB. 整个电路在1.8V供电电压下,消耗电流约31mA。     

一种对讲机射频前端模块的实现

本次设计的对讲机射频前端,采用高集成度的射频功率放大集成技术,可以取代传统复杂的电路设计,使对讲机的射频前端更加的简洁化,智能化。设计的整体方案是射频放大电路、电压控制电路,射频匹配电路、开关控制电路以及射频滤波电路完全的高度集成在一个模块上,大大节约了空间和设计成本。     

微波低噪声放大器的设计与仿真

低噪声放大器在接收系统中能降低系统的噪声和接收机灵敏度,是接收系统的关键部件。文中按照低噪声放大器电路的设计要求,完成了2GHz基站前端射频低噪声放大器的电路设计,并通过ADS仿真软件对电路进行仿真和优化。最终表明,采用本方案设计的LNA增益约为15dB,噪声系数约为1．2dB,性能稳定,完全达到了通信接收机中对LNA指标的要求。     

VHF跳频电台接收机射频前端的仿真设计与研究

通过对VHF跳频电台接收机射频前端设计指标和具体结构的介绍,运用Agilent公司的射频设计仿真软件ADS,对整个接收机射频前端电路进行仿真和电路设计,构建了一个由保护电路、跳频预选滤波器、低噪声放大器和自动增益控制电路组成的射频前端电路模型,并对其进行仿真.最后的实验结果表明,所设计的射频前端的性能指标达到了系统的设计要求,并有所提高.     

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.     

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.     

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.     

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.     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.