结构单元对双负材料电磁特性的影响

采用S参数提取法、结合HFSS仿真对双负材料电磁特性进行了分析研究,导出了S参数提取技术的相应计算公式。通过调节金属丝和金属谐振环单元的内外环间距、开口间距及覆铜厚度,分析结构单元的变化对双负材料谐振频率、介电常数及磁导率的影响。结果表明:双负材料的谐振频率随内外环间距的增大而迅速降低,随开口间距以及覆铜厚度的增大而缓慢增加。通过改变双负材料的结构单元可以实现对负介电常数和负磁导率频段的调控。     

谐振频率可调的开口谐振单环结构

开口谐振单环(Split Single Ring Resonatots,简记SSRRs)和开口谐振环(SRRs)一样可以激励磁谐振,从而实现负的磁导率.提出在SSRRs结构中引入平行于其开口边的金属线的方法设计了新的磁谐振单元,研究了金属线的引入对谐振频率以及负磁导率特性的影响.数值模拟结果表明:随着金属线长度l的增加,SSRRs的谐振频率随之减小;随着金属线与开口边的间距d的增加,SSRRs的谐振频率随之增加.金属线的加入不会对SSRRs的负磁导率特性产生重要影响,改变金属线的结构参数可以实现μ＜0频段的调控.所提出的新的磁谐振单元对于新型负磁导率材料和新型左手材料的设计具有重要的实际意义,也为新型无线通信材料的实现提供了可能.     

六边形开口谐振器的太赫兹特性

电磁超材料通常是由一些在介质基底表面上周期分布的亚波长谐振器组成的。它的特性在很大程度上取决于基底的性质和谐振器的结构细节。由于开口环谐振器(SRRs)可实现多种功能,因此在超材料中应用广泛。通过设计一种二维六边形SRRs阵列,利用时域有限差分方法(FDTD)研究了单元开口形式、单元周期和介质基底性质对其传输特性的影响。研究结果表明,开口形式可使超材料在1~2.5 THz处产生谐振响应,且介质基底的性质对该谐振特性的影响权重较大。     

应用于THz波的非对称双开口环传输特性研究

设计并制备了一种适用于太赫兹波段的非对称双开口环结构,数值仿真和实验测量了其传输性质.结果表明,垂直极化时样品在低频的0.540 THz和0.925 THz处存在谐振点,来源于左右两开口环的LC谐振,电流和电场分布主要集中在两开口环的开口处;而在高频处(1.885THz)谐振点的表面电流具有相反的两个环流方向,电流和电场分布于整个样品表面,此处的谐振来源于两开口环耦合后的偶极子谐振.当太赫兹波平行极化该样品时,原来两个低频的LC谐振消失.实验测量结果与数值仿真具有很好的一致性.此结构超材料的传输特性研究对太赫兹波调制器、滤波器、吸收器及偏振器等器件设计和制备具有一定的指导意义.     

异向介质体内太赫兹波增强效应及谐振特性研究

基于开口谐振环(SRR)的电磁响应特性以及严格电磁场理论,研究了由开口谐振环结构构成的异向介质体内的太赫兹波增强效应及谐振行为。仿真模拟了谐振环结构体内电场、电场能量密度和能流量的空间分布,讨论了电场能量密度随入射太赫兹波频率的变化规律。此外,还分析了谐振环结构参数对异向介质的谐振特性及其太赫兹波增强效应的影响。研究结果表明,在开口谐振环结构的开口缝隙处存在显著的太赫兹波增强效应,不仅电场显著增强,而且还会出现电场能量密度极值,并且,谐振时的电场增强效应比非谐振时明显增大。此外,谐振频率和电场能量密度均会随着谐振环结构参数的变化而呈现明显变化。     

基于新型互补开口谐振环的小型多频微带天线

基于提出的一种新型的具有超材料性质的互补开口谐振环,设计了一款小型多频带微带天线。首先设计了一个工作于6 GHz频段的微带天线,然后在此天线的金属接地板上刻蚀新型的互补开口谐振环。利用三维电磁仿真软件HFSS分别对新型的互补开口谐振环和加载互补开口谐振环的天线进行仿真分析,并最终设计了一款小型化的天线。仿真分析结果表明,在相同的谐振频率下,加载了新型互补开口谐振环的小型化天线的尺寸与普通天线相比,尺寸减小了25.85%,并且在6 GHz,7.07 GHz,7.73 GHz三个频率处产生了谐振,实现了天线的小型化和多频化。     

基于SRR结构的多频带频率选择表面

为实现频率选择表面(FSS)的多频带特性,将开口谐振环(SRR)结构引入多频带FSS的设计中.基于等效电路和仿真模型分析了单个SRR的电磁谐振特性,及其作为FSS结构单元而产生的电磁耦合.最后,利用有限元仿真软件HFSS计算了理想状态下无穷大周期性结构的多频带FSS,并通过对FSS的传输和反射频谱研究,揭示这种FSS谐振频率与SRR结构基本几何参数的内部关系.     

微波波段金属开口谐振环对的共振模劈裂现象研究

通过理论分析、电磁仿真和实验测量,研究了U形金属开口谐振环对(Split Ring Resonator Pair,SR-RP)在微波波段的电磁响应。利用等效电路方法研究SRR及SRRP的电磁响应特性,解释了SRRP构成的周期阵列中由于电磁耦合作用引起的共振模劈裂现象。并通过电磁全波仿真与实验测量,进一步研究了构成SRRP的两谐振环的夹角变化引起的传输特性的变化,传输曲线上的共振模劈裂程度随着两谐振环夹角在0°~180°范围内的变化呈现先减小后增大的变化趋势。     

开口金属环的磁谐振理论修正模型

研究了开口金属环周期性阵列的磁谐振特性,推导了开口谐振环周期性阵列电磁特性分析的理论模型,提出了一个金属内外环的有效间对面积因子,并基于该因子修正了Pendry模型中磁谐振频率的表达式;数值算例表明改良的理论模型具有更高的预测准确度。本文提出的有效间对面积因子X=3,对于开口谐振环阵列这一典型的电磁结构的性能分析来说,其修正模型的指导性是可靠的。     

带有开口谐振环引向器的新型端射天线设计

设计一种带有开口谐振环(SRRs)引向器的新型端射天线。天线由反射板、地板、辐射单极子和开口谐振环组成。天线的反射板结构使天线在低频处阻抗匹配,有效地提高了天线带宽;用六对开口谐振环结构作为天线的引向器,很好地实现了天线的高增益。仿真和实测结果表明,天线阻抗带宽达到73.7%(2~4.21 GHz),增益为4.3~10.3 dB;在天线的带宽内,天线的辐射方向图稳定,设计的天线满足S波段无线通信领域的需求。     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

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.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

A Versatile Mixed-Signal Pin Approach for Cost-Effective Test of Automotive ICs

Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

Optical vibration and deviation measurement of rotating machine parts

It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer （LDV）.