卫星赋形天线矩形同轴线馈电网络的FDTD分析

采用时域有限差分（FDTD）方法分析了构成卫星赋形天线馈电网络（BFN）的矩形同轴线各种不连续性结构的散射特性。该方法通过模拟波的传播过程直接求解结构的散射参数,与模匹配方法相比,分析过程大为简化,将计算结果与实验值进行了比较,二者吻合很好,充分证明了本文方法的有效性和精确性。     

时域有限差分法分析有源天线

本文采用时域有限差分方法（ＦＤＴＤ）分析了有源天线，讨论了采用时域有限差分法对有源器件的建模问题。在本方法中由于有源器件的大信号模型被直引入到时域场分析中，从而能得到十分有效的全波瞬态分析，计算结果和谐波平衡法计算结果及实验比较，验证了该方法的可行性。     

线天线输入阻抗的变分原理结合FDTD求解

将变分原理与时域有限差分（FDTD）法相结合，求解了对称振子的输入阻抗，克服了直接用FDTD的V/I定义式求天线输入阻抗的不准确性。文中方法避免求解表面散射场时的数值微分，减少了计算误差，获得了较好的结果。     

地下三维目标电磁散射特性研究

本文推出集总电阻加载圆柱形天线在时域有限差分（FD-TD）法中的计算公式。对Mur二阶吸收边界条件在三维FD-TD法计算中的稳定性进行了研究，提出保证Mur二阶吸收边界条件稳定所必须注意的问题。在集总电阻加载圆柱形天线激励下，对色激媒质中三维目标的瞬态电磁散射特性进行了计算和分析，并将部分计算结果与实验测试的结果进行了比较，二者具有比较好的一致性。研究了色散媒质和目标特性对目标回波信号的影响，并对有耗媒质中细导线型目标的瞬态散射机理进行了分析。     

双极化口径耦合微带天线FDTD分析

本文应用时域有限差分法（FDTD）分析了双极化口径耦合多层微带贴片天线。文中结果表明,FDTD在分析多层复杂结构的微带天线时是非常有效的。采用Gauss脉冲激励,通过FFT,一次计算就可得到天线谐振频率、耦合、频带宽度、增益等参数的宽频带特性。计算结果对天线的优化设计具有一定的指导作用。     

复杂环境中短波天线的MoM/FDTD混合法分析

利用电磁场数值计算方法中的矩量法/时域有限差分（MoM/FDTD）混合方法,分析了复杂环境中短波天线的电磁辐射性能,建立了短波双极天线的自由空间模型。采用矩量法和时域有限差分法相结合,对其模型进行仿真计算,并将计算结果和已有的文献进行比较,验证了混合方法计算结果的可行性、准确性。总结了该模型对短波天线远区场影响的有益经验,为改善短波天线性能提供了设计参考。     

时域MEI方法在矩形导体柱散射问题中的应用

本文用时域有限差分法（FDTD）模拟二维矩形导体柱的电磁散射场，采用时域不变性测试方程（MEI）作为吸收边界条件对该散射场进行求解。将所得计算结果与截断边界网格点采用Mur二阶吸收边界条件所得的数值结果相比较，两者吻合很好。结果表明使用时域MEI方法作为吸收边界条件能有效缩短截断边界与物体边界的距离，且能得到足够精确的解。     

地下三维目标电磁散射特性的研究

本文推出集总电阻加载圆柱天线在时域有限差分（ＦＤ－ＴＤ）法中的计算公式，对Ｍｕｒ二阶吸收边界条件在三维ＦＤ－ＴＤ法计算中的稳定性进行了研究，提出保证Ｍｕｒ二阶吸收边界条件稳定所必须注意的问题。在集总电阻加开圆柱形天线激励下，对色散媒质中三维目标的瞬态电磁散射特性进行了计算和分析，并将部分计算结果与实验测量的结果进行了比较，二者具有比较好的一致性。研究了色散媒质和目标特性艰目标回波信号的影响，并对有     

渐变开槽相控阵天线的FDTD分析

对UHF波段无限大开槽阵列天线进行了时域分析,应用Floquet原理对阵列的结构进行区域划分,同时采用时域有限差分法（FDTD）进行数值仿真,研究了作为相控阵天线应用时的频率和空间扫描特性,给出了数值计算结果,得到一些有参考价值的结论。     

用空间传播和RCS模型研究RFID装置最大识别距离

通过自由空间传播模型和雷达散射横截面（RCS）模型，研究了反向散射射频识别（RFID）装置的最大识别距离。用高频电磁场仿真软件FEKO对折叠偶极子标签天线进行了建模仿真，得到天线的远场辐射方向图、输入阻抗以及在不同负载情况下天线的单站RCS值。经过理论分析和仿真计算，由两个电波传播模型分别得出RFID装置可能的最大识别距离。最后比较了两种模型的计算结果，较小的距离即为该反向散射RFID装置的最大识别距离。     

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.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

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.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

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.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.