双频带柔性人工磁导体结构研究

人工磁导体能够减小人体生物组织对人体通信天线性能的影响。根据等效电路模型以及软件优化仿真明确3*3人工磁导体结构单元形状和尺寸参数。结合人体手臂生物组织模型进行仿真,以0.05 mm 厚度聚酰亚胺为基底材料、铜为导电材料,加工制作正方形人工磁导体结构辐射单元和天线并在人体手臂进行实测。仿真与测试结果表明辐射单元结构尺寸设计为S1 =24 mm,S2 =23 mm,S3 = 12 mm,S4 = 7 mm,能够确保天线工作在2.45GHz 和5.80 GHz 双频段,将人体SAR值在2.45 GHz 时降低了86%,在5.8 GHz 降低了64%,AMC 结构和天线相距5 mm 时,实测天线回波损耗S11参数曲线与理论结果相符,可以满足双频带安全人体通信的应用需求。     

基站天线辐射单元组阵方式的研究

文章主要针对目前基站天线多采用相同的辐射单元组阵的现状,提出了采用不同的辐射单元组阵以改善基站天线辐射参数指标.通过专业电磁仿真软件Ansoft HFSS建模仿真,结果显示,在1.7GHz～2.7GHz的频带范围内,不同辐射单元组阵可有效改善基站天线的方向图指标.     

一种圆极化可重构微带天线的设计

对圆弧寄生单元微带天线进行了理论分析,设计了一种圆极化可重构的圆形微带天线。该天线通过电控开关控制圆弧寄生单元的状态,从而实现左、右旋圆极化的转换。并利用仿真软件HFSS13.0对天线的特性进行了仿真验证。结果表明,在天线回波损耗S11<–10 dB时,该天线在频段为2.38~2.51 GHz,3 dB轴比带宽为30 MHz,且最大辐射方向处正交极化差达20 dB以上。天线的整体辐射性能良好,且结构简单易于实现,很容易在低频段匹配到50,能够满足WLAN在2.4 GHz频段的要求。     

一种圆极化可重构微带天线的设计

对圆弧寄生单元微带天线进行了理论分析,设计了一种圆极化可重构的圆形微带天线。该天线通过电控开关控制圆弧寄生单元的状态,从而实现左、右旋圆极化的转换。并利用仿真软件HFSS13.0对天线的特性进行了仿真验证。结果表明,在天线回波损耗S11<–10 dB时,该天线在频段为2.38~2.51 GHz,3 dB轴比带宽为30 MHz,且最大辐射方向处正交极化差达20 dB以上。天线的整体辐射性能良好,且结构简单易于实现,很容易在低频段匹配到50,能够满足WLAN在2.4 GHz频段的要求。     

宽频带盘锥天线的研究与设计

设计了一款工作于700MHz～3GHz的宽频带盘锥天线。在参考现有文献得出盘锥初始模型的基础上,通过高频电磁场仿真软件HFSS对各参数进行参数优化仿真,最终得出最佳值。该天线在700MHz～3GHz的频段内VSWR<2,H面辐射方向图具有全向性,并最终通过仿真和实测验证了其性能。     

人体中心网络微带缝隙天线设计和研究

设计了一款小型微带缝隙天线.通过电磁仿真软件CST的参数优化功能,对微带缝隙天线缝隙的长度、宽度、馈电点等参数进行优化,得到了工作频率为2.45GHz,带宽100 MHz、阻抗匹配良好、辐射效率较高的用于人体中心网络的微带缝隙小型天线,根据仿真设计,制作了天线,测试结果和仿真结果吻合较好.     

一种新颖的双频微带天线设计

为了满足WLAN和Wi MAX双频无线通信,设计了一种结构简单的1/5双频微带贴片天线,该天线采用50Ω微带线馈电,集总端口激励方式。通过HFSS13.0仿真分析,天线可同时工作于Wi MAX(5.25 GHz)和WLAN(2.45 GHz)频段。仿真结果显示,优化后的天线在2.45 GHz和5.25 GHz频段的相对带宽分别为10%和22%,最大增益分别为2.33 d B和3.10 d B。带宽满足微带天线带宽的要求,且天线的辐射特性良好,结构简单,易于生产,有很大的应用前景。     

同频方向图可重构印刷振子天线设计

为了在同一副天线、同一频段实现方向图可重构,提出了一种方向图可重构印刷振子天线。通过改变开关的状态,天线实现单极子和带反射器的偶极子两种工作方式。单极子辐射全向方向图,带反射器的偶极子辐射方向图为定向。利用Ansoft HFSS10.0 仿真软件对天线尺寸进行了分析和优化。仿真结果表明：开关断开、闭合时,天线实现 了在2.34～2.64GHz 工作频带上的定向和全向方向图;在2.45GHz 处,最高点增益分别为6.7dB 和3.1dB。     

加载超表面的双频紧凑高隔离阵列天线设计

为了减小极小距离多输入多输出(multiple-input multiple-output, MIMO)天线之间的相互耦合,设计了一种极紧凑的高隔离度的双频MIMO贴片天线,谐振频率分别为2.45 GHz和3.5 GHz。该MIMO天线由两个对称的双层U型槽贴片天线组成,其中边与边的距离为0.5 mm(0.004λ0,λ0为中心频率2.45 GHz时的自由空间波长)。利用不同宽度的双层金属线切割对作为超表面单元,该超表面体积紧凑,可以显著降低天线单元之间的相互耦合。仿真和测量结果表明：在天线工作频段2.4～2.5 GHz和3.4～3.6 GHz范围内,单元间的隔离度可以提高到30 dB以上,并且两个天线端口阻抗匹配良好,同时在低频段的总效率提高了9%左右;两天线间的包络相关系数(envelop correlation coefficient,ECC)在2.45 GHz时由0.33降到0.01,在3.5 GHz时由0.09降到0.006,所设计天线具有良好的辐射性能。     

双频段体表/体外双模式可穿戴天线设计

基于特征模理论分析方法,设计了一款2.45、5.8 GHz频段的体表/体外双模式可穿戴天线。在三角形的辐射贴片和接地面之间加载一段微带线,在2.45 GHz引入一个具有全向辐射特性的新模式,加上三角形贴片本身在5.8 GHz具有的定向辐射特性,组成了一个双频段双模式可穿戴天线。天线的仿真结果表明,在低频处实现全向辐射特性,阻抗带宽为1.6%(2.45～2.49 GHz),可用于体表通信模式;在高频处具有定向辐射特性,阻抗带宽为4.3%(5.67～5.92 GHz),可用于体外通信模式。     

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.     

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.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks