基于旁瓣对消器的自适应零陷优化设计

现有的零陷展宽算法忽略了锥化矩阵的相位信息,在对抗强方向性、大偏差角干扰时,零陷深度变浅,干扰抑制性能严重下降。该文以虚拟空域密集干扰为切入点,推导并提出一种可用于旁瓣对消器的自适应零陷优化设计算法。该算法通过对辅助阵列数据的自协方差矩阵和主辅阵列数据的互协方差矩阵同时进行重构实现零陷区域的自适应控制,锥削矩阵只与阵元位置和展宽宽度有关,无需干扰信息,可以离线生成,不占用系统运算资源。仿真结果表明,该方法可以实现零陷区域的自适应展宽,提高非平稳干扰抑制的稳健性。     

基于功率估计的高动态GNSS抗干扰零陷展宽算法

全球卫星导航系统(GNSS)接收机在高速运动状态下时,干扰来向的快速变化会导致阵列抗干扰算法性能下降,为此,提出一种基于功率估计的抗干扰零陷展宽算法。根据特征值将采样协方差矩阵划分为信号子空间与噪声子空间,通过子空间投影确立信号导向矢量与功率的线性关系;利用线性关系估计干扰功率,并根据零陷展宽需求重新设定干扰区域内的信号功率;最后,以干扰区域内功率的估计值为基础重构干扰加噪声协方差矩阵,求解阵列权矢量。仿真表明,相比其他零陷展宽算法,所提算法在相同展宽下具有更深的零陷,阵列输出信干噪比也有所提升。     

一种零陷展宽稳健旁瓣相消算法

受到实际条件的限制,自适应旁瓣相消器通常不可能频繁地更新自适应权值,使得其在对抗空域非平稳干扰时,会出现权值失配现象,严重影响干扰抑制性能。该文从空域密集干扰产生宽零陷的角度出发,提出一种适用于自适应旁瓣相消器的零陷展宽算法。该算法通过对主通道的合成权值和辅助天线间的协方差矩阵同时进行锥削实现零陷展宽,锥削向量和锥削矩阵只与阵元位置和展宽宽度有关,可以离线计算,在线直接调用,实现简单,适合工程实际使用。仿真实验证明,该文方法可以有效展宽自适应零陷,增强自适应旁瓣相消器对抗空域非平稳干扰时的稳健性。     

一种宽零陷的自适应波束形成算法

自适应波束形成技术能有效地接收目标信号并抑制干扰,是阵列信号处理中的一项关键技术。为了应对快速运动干扰或平台转动等引起的自适应权值和数据失配,增强算法的鲁棒性,可以采用零陷展宽技术。通过Capon谱重构干扰加噪声协方差矩阵,可以根据需要设置零陷宽度和零陷深度,从而大大地提高算法的鲁棒性。通过与现有算法的比较,该方法能得到更高的输出信干噪比,并且能加深零陷深度,需要的快拍数也较少。     

一种运动干扰稳健滤波方法

传统的阵列干扰抑制算法假设天线阵列与干扰之间相对静止,完成干扰抑制,当阵列与干扰之间存在相对运动时,存在协方差矩阵估计快拍数不足的问题,从而导致阵列滤波性能下降。针对上述运动干扰稳健滤波问题,提出了一种算法对现有零陷展宽技术抗运动干扰方法进行改进。一方面,将零陷展宽技术与导数约束方法相结合,用得到的新协方差矩阵求自适应权值;另一方面,为了提高自适应波束形成对噪声和误差的稳健性,引入了对角加载技术,加载量通过寻找协方差矩阵的特征值曲线拐点得到,有效避免了加载量过大导致的干扰信号被淹没以及加载量过小导致噪声分量引起性能损失的问题。该算法对零陷展宽系数选取依赖性较低,且对角加载量不需要设置固定的经验值,有利于稳健运动干扰滤波,适用于实际工程中先验信息不足条件下的自适应阵列抗运动干扰情况。     

一种相干信号自适应波束形成零陷展宽算法

针对传统自适应波束形成器在相干干扰位置出现快速变化时,输出性能下降,甚至干扰抑制失效的问题,提出了一种相干信号自适应波束形成零陷展宽算法。首先,对接收数据协方差矩阵进行解相干处理得到Toeplitz矩阵;其次,对协方差矩阵进行重构和优化;最后,进行零陷展宽和对角加载处理。仿真结果表明：该算法不仅能对相干干扰自适应形成宽零陷,而且可以灵活地控制零陷的深度和宽度;与Mailloux算法相比,在输入信噪比较高的情况下,该算法能得到更低的波束旁瓣电平和更高的输出信干噪比     

一种适用于任意平面阵的零陷展宽并加深算法

高动态环境下常规协方差矩阵锥化(CMT)零陷展宽算法在零陷展宽后深度会变浅,且应用于二维平面阵上时需要信号来向信息。为此提出了干扰来向扰动服从Laplace分布的零陷展宽并加深算法。该算法首先对信号模型重新建模,并基于模型推导了二维Laplace算法;之后利用投影变换提取出数据中的干扰分量,并通过系数加权增强干扰分量;重新构造协方差矩阵,利用零陷展宽算法扩展干扰来向;最后结合功率倒置(PI)算法完成干扰抑制。仿真实验表明,所提算法不但能够在零陷展宽算法的基础上实现零陷加深,提高了抗干扰算法稳健性,并且能够适用于任意平面阵。     

一种新的波束形成零陷展宽算法

针对自适应波束形成器在干扰位置出现扰动时的输出性能下降问题,该文提出一种新的零陷展宽算法。该算法基于投影变换与对角加载技术的结合,首先利用投影变换技术对阵列接收数据进行预处理,结合对角加载技术,以此构造出一个新的协方差矩阵替代原来的协方差矩阵,再利用自适应波束形成技术得到零陷展宽后的波束图。仿真结果表明,该方法能有效展宽波束零陷宽度,加深零陷深度,达到抑制位置出现扰动的强干扰信号目的。该算法易于求解,对参数的选取具有较强稳健性,在低快拍条件下,依然能有效地工作,增强了自适应波束形成器稳定性。     

零陷展宽对角载入算法

提出了零陷展宽对角载入算法,该算法既解决了干扰在快速运动时,干扰零陷过窄的问题,又解决了协方差矩阵误差和导向矢量误差存在时,算法稳定性变差的问题。同时,通过对角载入因子和采样协方差矩阵间的关系确定了对角载入算法载入因子的值。计算机仿真结果表明该算法有很好的稳健性,以及较宽的零陷。     

抑制快速运动强干扰的稳健自适应波束形成方法

针对存在快速运动强干扰时自适应波束形成性能的严重降低,提出了一种稳健的自适应波束形成方法。该方法使用零陷展宽技术修改采样协方差矩阵,使其自动地在干扰方位形成展宽的零陷以抑制运动强干扰,同时采用对角加载技术,以增强此方法对系统误差的稳健性,加载量通过约束扫描向量的误差来确定。仿真结果表明该方法能有效地提高当存在快速运动的强干扰时自适应波束形成的性能。     

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.