基于微波光子相干接收的宽带射频前端技术（特邀）

提出了一种适用于电子战应用的宽带大动态微波光子射频前端方案,通过采用双边带抑制载波及微波光子相干接收技术,能够有效改善前端的噪声系数、无杂散动态范围等。在6~18 GHz工作频带内,该射频前端无杂散动态范围达到110 dB·Hz^(2/3)、噪声系数优于8 dB、多通道幅度一致性优于±1 dB、多通道相位一致性优于±10°,实现了宽带射频信号的高性能传输,同时满足阵列光学波束需求。     

一种提高无杂散动态范围的多通道信号接收方法

当大功率信号进入接收机后,将迫使模数转换器工作在非线性区,并导致接收信号中含有大量非线性杂散.为了抑制杂散并提高接收机对小信号的侦测能力,提出了一种具有无杂散高动态范围(Spurious-free Dynamic Range,SFDR)的信号接收方法.首先通过两路不同的通道同时接收信号,然后利用信号之间的频率差异识别杂散,最后在频域上通过频点替换方案抑制杂散.仿真与实验结果表明,当输入为双30 kHz窄带大信号时,该方案能使SFDR提升15 dB.     

宽带大动态射频光传输技术

宽带大动态的射频光传输链路是微波光子技术应用的基础。针对射频光传输对链路高动态范围的应用需求,分别介绍了多频点副载波复用数字预失真和多源非线性数字后补偿两种失真线性化技术的原理及其研究进展,这两种方法能较好地抑制信道间的交调失真和信道内的三阶交调失真。同时,将全光下变频技术引入到接收链路中,通过充分利用相位调制线性特性的优势,分析了基于相位调制及相干解调DSP处理的大动态光载射频传输系统,实验得到的宽带射频信号光传输系统的无杂散动态范围达到了128.8 dB.Hz2/3。     

高分辨率任意可重构微波光子滤波器EI北大核心CSCD

提出了一种能够实现任意滤波形状的高分辨率可重构微波光子滤波器方案。利用可编程光滤波器完成抽头系数的独立灵活配置,配合使用相干探测技术实现滤波器的正负抽头,从而可以完成滤波形状的任意可重构。研究表明一个大梳齿数量的平坦光频梳被作为光源可提高抽头数量,从而实现高分辨率的滤波器的重构。除此之外,通过预先引入色散,响应中的杂散也被有效地抑制。经仿真验证,该滤波器具有93 MHz的高分辨率,杂散抑制40 dB以上,创新性地构造了具有不同中心频率的低通、带通、高通、带阻滤波器,以及矩形、高斯形、sinc形等任意滤波形状,对于后续微波光子滤波器的研究起到了引导性作用。     

微波变频组件杂散信号分析与抑制设计

微波变频组件是通过一次或多次变频将微波信号变频至所需频率的器件,在变频过程中生成所需信号的同时也会混频产生多余的频率分量,这些频率分量对所需信号构成杂散信号必须予以抑制。基于降低杂散信号对输出信号的影响阐述了变频原理,具体分析了射频信号和本振信号混频后的频率分量,最后给出了一种变频组件的实现方法,实现了抑制杂散信号分量的目的。     

基于CORDIC算法的NCO

为了提高基于CORDIC算法NCO的无杂散动态范围,提出采用相位映射和相位抖动技术来提高无杂散动态范围.SIMULINK仿真结果表明改进后的NCO无杂散动态范围提高近10dB,充分说明了该方法的可行性.     

基于并联DPMZM的大动态范围微波光子混频系统

为了解决微波光子混频系统的非线性失真和动态范围受限问题,提出了一种基于并联双平行马赫-曾德尔调制器(DPMZM)的大动态范围微波光子混频系统。利用DPMZM实现射频和本振信号的并行调制,通过配置并行两路的电光调制指数及调制器的工作点,抵消输出中频信号中的三阶交调失真(IMD3),最终提高系统的动态范围。仿真结果表明,所提方案可将IMD3抑制17.7 dB,系统无杂散动态范围提高到127.8 dB·Hz 4/5。     

基于DDS的低杂散捷变频合成器设计

为了对抗有源干扰,雷达系统要求频率合成器具有频率捷变功能;同时要求其杂散抑制越高越好,特别是在输出信号带宽较宽的情况下更是如此。受体积和成本的限制,目前的捷变频频率合成器广泛采用基于直接数字合成（DDS）技术的变频方法。本文基于低杂散,对采用DDS的捷变频频率合成器技术进行了研究,并介绍一种采用时钟频率高达3．2GHz的新型DDS集成电路的低杂散捷变频频率合成器的设计与实现方法,设计得到的捷变频频率合成器带宽为250MHz,其杂散抑制指标可满足全频段优于-65dBc。     

高功率光放大器在载波抑制模拟光纤通信中的应用

系统地分析了高功率光放大器在载波抑制模拟光纤通信系统中对提高链路性能的显著作用.因为额外的光载波功率而引起较高的噪声指数,采用标准Mach-Zehnder电光调制器的模拟,光纤系统只能将无杂散动态范围限制在110 dB·Hz2/3范围内.通过引入高功率光放大器和利用光滤波器来抑制光载波,链路中的噪声指数可以显著地降低15 dB以上.当只有三阶畸变作为主要考虑因素的时候,理论分析证明无杂散动态范围能够达到121 dB·Hz2/3.     

一种扩大数据采集的无杂散动态范围的扰动方法

介绍了一种能够有效抑制杂散、扩大ADC的无杂散动态范围的扰动方法。仿真结果证明了该方法的有效性。     

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）.