低副瓣任意波束直接合成算法研究

在传统阵列天线波束赋形设计中，通过对阵元天线辐射方向图进行幅度相位加权，获得阵列合成方向图.通常阵元激励幅度相位权值的获取，取决于优化算法对目标方向图和阵列合成方向图的对比，通过对阵元激励幅度相位进行大量随机选参后，获得优化结果.由于算法通常是基于相关的阵元方向图，且算法中缺乏副瓣抑制机制，使得方向图合成效率不高且副瓣效果通常不理想.该文设计了一种任意波束直接合成算法.该方法首先在阵元方向图的基础上获得一组互相独立的高增益窄波束（自由基波束），然后基于此波束进行方向图的直接合成，使波束赋形问题统一到基于自由基波束权值运算的范畴内，对波束赋形问题进行了统一，避免了未知参量的随机优选过程，极大提升了阵列天线波束赋形设计的效率.同时在自由基设计的过程中结合了副瓣抑制机制，且这种副瓣抑制机制与波束赋形过程互相独立，使合成波束的副瓣天然地具备了低副瓣的特征.     

某相控阵天线幅相分配网络的设计与实现

在某相控阵天线设计中,需要对铅垂放置的天线单元的方向图赋形.本文采用最小二乘法得到天线单无各振子电流的幅度和相位,并用MATLAB进行方向图计算仿真;根据计算结果,设计了幅相分配网络,并用HSFF仿真软件进行模型仿真;应用矢量网络分析仪对实物进行测量.测量结果表明,天线单元铅垂方向图与计算、仿真结果一致,满足设计要求.     

米波圆环天线阵的方向图综合研究

利用通过遗传算法和粒子群优化方法对米波圆环阵列的幅度和相位加权进行设计,实现方向图增益、副瓣电平和方向图凹口的优化综合.以位爬山法和相位局部搜索技术为辅助,得到了较为理想的方向图结果,同时将GA和PSO方法的计算效率进行了比较,后者操作更简单,占用的计算资源更少,方法和结果可作为共形阵方向图设计参考.     

基于遗传算法的阵列天线方向图综合

本文介绍了用遗传算法对阵列天线方向图进行综合的方法。首先利用泰勒及切比雪夫幅度分布的方向图作为优化目标进行幅度优化,验证了遗传算法用于阵列天线方向图综合的可行性。然后给出了某S波段成像雷达天线阵遗传优化结果的幅相分布曲线。最后将优化方向图与标准遗传算法综合的结果比较。结果证明文中所述方法能更好的逼近目标方向图。     

一种基于DFP-BFGS算法的阵列天线波束赋形方法

为优化得到给定形状的目标方向图,引入了一种基于DFP-BFGS无约束最优化算法的数值方法.优化过程是先对阵列各单元的激励幅度和相位同时优化,然后对得到的阵列激励幅度数据进行部分调整,使其更加均匀以便于馈电网络的设计.最后固定激励幅度分布,仅对相位数据进行优化.在实现对方向图主瓣波束赋形的同时,得到了较为均匀的激励幅度分布.该优化方法具有应用灵活和结果可调控的优点,是一种实现阵列天线波束赋形的实用方法.     

基于DEA的圆阵旁瓣电平优化方法

由于圆形阵列所具有的特性,使其正得到日益广泛的应用,但是圆阵方向图却具有相对主瓣较高的旁瓣电平。为此,文中针对均匀圆形阵列的天线单元,应用差分进化算法,分别进行唯相位、唯幅度、相位一幅度的方向图综合方法,进行旁瓣电平的优化。仿真结果表明：这些方法可有效地降低圆阵的旁瓣电平,为解决此类问题提供了有益的参考。     

基于粒子群算法的天线阵方向图优化

雷达阵列天线常涉及方向图综合,而天线阵综合常常是利用优化算法优化单元幅相及间距等参数的过程。粒子群算法具有理论简单、参数少和易于实现等特点,文中基于这一简单易行的优化算法,给出一种阵列天线赋形波束综合方法。通过优化阵列天线中各单元的馈电幅度和相位同时实现主瓣的赋形和副瓣电平的抑制,或通过仅相位加权实现主瓣波束赋形,得到优良的余割平方赋形。通过实例设计验证了粒子群算法优化天线阵方向图的有效性。     

相位和差单脉冲相控阵天线方向图仿真与性能分析

以相位和差相控阵为例对和差方向图仿真进行研究,给出了相位和差单脉冲相控阵天线方向图仿真模型。以幅度加权为例,给出了和差方向图的数值仿真结果,并分析了方向图波瓣分布特点。对相位和差相控阵单脉冲测角原理、测角性能曲线和测角误差原因进行了分析。天线方向图计算机数值仿真方法可以为天线系统设计和天线参数测试提供参考。实践证明该仿真方法是非常有效的,并在实际天线测试和性能分析中得到应用。     

基于多任务贝叶斯压缩感知的稀疏可重构天线阵的优化设计

建立方向图可重构天线的联合稀疏模型,基于多任务贝叶斯压缩感知理论提出一种稀疏可重构天线阵的优化设计方法.该方法在实现方向图精确重构的同时可以大幅减少天线数量,节省平台空间,降低设计成本.首先基于多任务贝叶斯压缩感知理论建立多目标方向图的稀疏优化模型,根据权值向量的先验概率分布,利用快速相关向量机估计超参数的最大后验概率来得到多组阵元位置及其激励,实时改变激励以获得不同方向图的稀疏逼近.仿真验证了该方法能够以较少的阵元个数和较高的方向图拟合精度快速实现方向图重构.     

变尺度算法应用于阵列天线综合

本文将传统算法——变尺度算法应用于阵列天线综合领域中。首先优化了线阵各单元的激励幅度,使之形成泰勒方向图,从而验证了该方法的有效性及高效性;然后针对某成像雷达的平方余割方向图,对线阵各单元的激励幅度和相位进行优化,在较短的时间内,即可得到令人满意的结果,能够良好的逼近目标方向图。     

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.     

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.     

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.     

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.     

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