新型NRD波导漏波天线特性分析

本文利用多模网络理论结合模匹配技术对任意横截面NRD波导漏波天线的辐射特性作了系统的分析,这些天线可以作为低成本的实用天线应用在毫米波系统中.文中着重研究了结构参数的变化对天线辐射特性的影响.这些计算结果对这类新型漏波天线的设计和确定NRD波导作为传输结构时的制作容差有重要的指导意义.     

用区域分解法分析基于NRD波导结构的漏波天线

提出了利用区域分解结合频域有限差分法,分析基于NRD波导结构的漏波天线。用区域分解法将原问题分解为若干子问题,大大缩小稀疏矩阵的规模,从而使得求解大尺寸问题成为可能。文中首先介绍了区域分解法在分析三维电磁问题中的实现,并计算了典型结构金属块的散射问题,用于验证算法的正确性;最后分析了一种基于NRD波导结构的漏波天线,并与实验值进行了比较,说明了方法的有效性。同时还给出了一种能够有效改善该天线性能的改进型漏波天线结构的分析结果。     

基于FDTD的微带缝隙漏波天线分析

应用时域有限差分法(FDTD)对微带缝隙漏波天线进行分析,直观地得到了微带缝隙漏波天线内部的电场分布。提出了一条有效的经验公式,成功地计算了微带缝隙漏波天线的漏波传播系数,与实验数据吻合较好。比较了不同缝隙宽度和微带宽度对微带缝隙漏波天线性能的影响。证明了在微带漏波天线上开缝可以有效地减少天线尺寸及降低天线的工作频率。     

X波段镜象回收混频器

介绍了介质谐振器镜象回收混频器和平衡式镜象回收混频器。叙述了它们的工作原理、电路设计及实验结果。测试结果表明两种镜象回收混频器,外镜频抑制度大于18dB,且由于回收了内镜频,降低了变频损耗,使噪声系数得以改善。     

导体调制周期介质平面天线

一种新型的导体调制周期介质平面天线在毫米波段的应用业已提出,并进行了系统的研究。本文对上述天线应用二维周期导纳表面理论进行了初步的理论分析、数值计算和实验研究。所研制的8mm波段导体调制周期结构漏波天线的平面口径为9090mm2,其它各项主要性能良好。     

12GHz正交场混频器及镜象回收

1.前言日本于1978年4月发射了一颗中型实验广播卫星(BSE),以成形波束覆盖日本全境。BSE溢入我国东部地区的场强已减弱甚多。为了对这一微弱信号进行收测,需要用灵敏度较高的接收设备。1978年10月,我们在东北某地对BSE进行了收测,使用的接收天线是直径3米的卡塞格伦型天线,用正交场混频器直接混频并加镜象回收的方式,得到了较好的收测效果。应用镜象回收技术降低了噪声系数,与     

层状媒质上有限长度偶极天线的辐射场

本文采用有耗媒质的复镜象理论与几何光学法相结合的方法计算了两层导电媒质上有限长度偶极天线的辐射场,节省了计算时间,测试值与计算值基本一致。     

可重构天线的FDTD研究

基于共面波导漏波结构,提出了一种方向图可重构的天线结构,该天线采用开关重构漏波结构周期,并使用两个馈电端口.采用时域有限差分法(FDTD)对天线的可重构特性进行了仿真分析.计算结果表明该方法能快速准确地确定周期结构漏波天线设计中的关键参数-基波传播常数.     

介质镜象线的阻抗匹配器

本文分析了介质镜象线的波阻抗与几何尺寸和频率的关系;研究了阻抗匹配的必要性和可能性;提出了一种选优的匹配器。对于阻抗比为4.7的两截介质镜象线,得到驻波系数S1.10的带宽达10.5 GHz的宽带特性。选优匹配器的性能优于用经典方法设计的匹配器。     

一种镜象单元天线的极稀阵列

一、引言本报告介绍了从缝隙、偶极了或螺旋一类普通的辐射单元中挖掘提高可用定向增益潛力的一些研究结果。G.V.Trentini在一篇短文中曾指出,单个辐射单元增益能任意增加,只要把单元放置在一是半反射器而另一是全反射器的两反射平板之间。这种天线的工作是以镜象或反射原理为基础的。因此,把这类天线称为镜象单元天线。镜象天线的基本原理和研制以及用它作为阵列单元的可行性是本报告研究的课题。二、工作原理天线背后放一块大导电屏能屏蔽天线的背向辐射,也能影响(取决于其间距)前向波瓣。但法线方向的方向性系数只能改善到一定限度,因为反射屏的照射不是最佳的,而且从更远区域反射的射线产生不同相的成分。     

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