基于基片集成波导技术的超宽带八木天线

为便于系统集成和简化馈电电路,利用基片集成波导技术设计新型八木天线.通过引向器异面分置来提高增益,提出了X波段基片集成波导八木天线,并分析了引向器个数对天线增益和工作带宽的影响.利用增加激励器个数和改变馈电结构来扩展带宽,设计了单模和半模基片集成波导双激励超宽带八木天线,仿真和测试结果表明,基片集成波导双激励八木天线的工作带宽超过40％,带内增益均高于7.0 dBi,中心频率处为9.0dBi,可以广泛应用于雷达和通信系统中.     

准八木型宽带高增益微带天线

基于八木天线的结构设计并制作了一个准八木型宽带高增益微带天线,利用三维电磁仿真软件(Ansoft HFSS)进行仿真设计,在已有的单一引向器结构的基础上,通过增加引向器数量实现了高增益和较宽的带宽。实际测试表明:天线工作频段在4.8~6.4 GHz,在中心频率5.6 GHz处,峰值增益约为10.2 dB,前后比约为21dB,与仿真结果基本吻合。另外,还给出了准八木型高增益微带天线的设计过程,并对具体结构和参数的选择对天线性能的影响进行了比较和讨论。     

倾斜波束微带磁八木天线设计北大核心CSCD

在基片集成波导(Substrate Integrated Waveguide,SIW)技术的基础上,文中提出了一种具有垂直极化倾斜波束辐射特性的微带磁八木天线设计方法。该方法将SIW作为磁八木天线的激励单元,采用微带线-锥形转换器为其馈电,利用接地的微带贴片构成磁偶极子引向器,引导场能量从SIW向引向器单元传播,从而实现了垂直极化辐射特性。该天线结构省去了反射器单元,简化了八木天线设计过程。仿真结果表明:该天线相对带宽为16.84%,方向图呈现出垂直极化倾斜波束的辐射特性,并且适当增加引向器的数量可以使天线波束倾斜角度增加。加工制作了天线实物并进行了测试,实测与仿真结果吻合较好,验证了该方法的有效性。     

一种S波段宽带单极八木天线北大核心CSCD

在传统单极八木天线的基础上进行改进,在单极子左右两端放置寄生单元增加了驻波带宽,把天线引向器长度设计成非均匀扩展了方向图带宽,在反射器后面放置一个反射板进一步提高了低频增益。使用Ansoft HFSS软件对天线进行了建模仿真并加工了实物进行测试,实测反射系数S11在2.2 GHz^5.2 GHz频带内小于-10 d B,相对带宽达到81%。增益方向图在2 GHz^4 GHz频带内不发生畸变,相对带宽66.7%。实测结果在3.9 GHz处达到最大增益11 d B,端射特性明显,仿真与实测结果吻合很好。     

一种微带准八木天线的改进设计*

在RamadanA.Alhalabi设计的准八木天线基础上进行了改进设计,采取增加展宽天线带宽的两个寄生贴片和振子耦合枝节和提高天线增益的天线背面引向振子组,减小天线体积的馈线结构等改进措施,从而达到展宽天线相对带宽的目的.使用Ansoft HFSS软件对改进天线进行仿真实验和对实物天线进行测试,结果表明:这种改进型天线结构设计合理,其相对带宽都大于20％ (VSWR≤2),在2.4GHz处的增益都大于10dB,天线具有良好的性能,从而拓宽了该准八木天线的应用范围,而且紧凑的结构和较小的尺寸便于天线组阵.     

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。     

一种具有宽带宽角特性的改进型准八木天线

准八木天线是由巴伦、辐射单元和引向器构成的一种微带天线,文中提出了一种具有宽带、宽角特性的改进型准八木天线。通过CST仿真分析软件,对振子双臂后折和利用矩形微带贴片对辐射单元进行改进的微带贴片式准八木天线进行仿真分析,仿真和实测结果显示,微带贴片式准八木天线在带宽达到40%频带内（8 GHz～12 GHz）,驻波比（VSWR）≤2,3 dB的波束宽度均能达到120°以上。     

新型定向超宽带天线

基于圆片单极天线是一种结构简单的超宽带天线,研究了一种新型的超宽带天线,它将4个圆片单极天线垂直交叉放置作为馈源并采用平板反射面,实现定向以及双极化或圆极化特性。分析了2种变形形式:将平板反射器换为抛物面反射器,实现高增益特性;将圆片振子变形,实现更宽的低频端阻抗带宽。通过电磁仿真软件,计算了天线的S参量和辐射方向图随频率的变化规律。分析表明文中的天线对于传统的圆片单极天线有了有效的改进,实现了超宽带、定向辐射、双极化、圆极化、高增益等不同的特性,它们在卫星通信和移动通信中具有良好的应用前景。     

基于SSPPs的低剖面宽带八木天线阵列设计

提出了一种基于新型人工表面等离子体激元(Spoof Surface Plasmon Polaritons, SSPPs)馈电带有引向器的低剖面宽带八木天线阵列。天线阵列包括两部分:基于人工表面等离子体激元波导的四路宽带功分器和八木天线阵列。人工表面等离子体激元具有高的场局限性,将信号束缚在人工表面等离子体激元的凹槽结构中保证了信号的高效传输,减少了传输损耗。八木天线通过进一步加载引向器结构能够实现端射辐射特性。测试结果表明:天线阵列的回波损耗在4.5 ~6.05 GHz 频率范围内小于-10 dB。天线阵列实际增益在4.5 ~ 6.05 GHz 范围内最高可达11.1 dBi。     

一种P波段宽带端射天线设计

设计了一种P波段的宽带端射天线。该天线以传统八木天线为基础,将振子尺寸缩小为原来的一半,并将振子放置在金属平板上,进而对天线的反射器和引向器进行改进,并通过对天线参数的仿真优化,最终将天线的带宽扩展到了38.4%,并保证了频带内相对较高的增益。仿真结果表明,天线能够在0.5~0.8 GHz的频带之内实现良好端射,并保证带内回波损耗均在-10 d B以下,整个频段内天线的方向性系数均在8.6 d Bi以上。     

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.     

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.     

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.     

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）.