毫米波连续波雷达载波泄漏对消——理论分析与系统仿真

对限制连续波体制雷达系统作用距离的载波泄漏问题仔细地作了探讨，对各种连续波体制载波泄漏有源对消方法进行了理论分析，并针对毫米波宽带调频雷达实际泄漏信号的特点进行了对消环路的系统仿真。结果表明设计良好的对消系统能有效地抵消载波泄漏功率达３０￣６０ｄＢ，对进一步作实验研究提供了理论基础。     

一种新的警戒雷达抗同频干扰技术

研究了同型号警戒雷达间同频干扰抑制问题,利用机械扫描警戒雷达扫描周期固定不变的特点,提出了一种新的旋转周期动目标检测( MTI)对消的同频干扰抑制方法。建立了警戒雷达方位扫描周期内的同频干扰模型,分析了常规MTI技术无法消除同频干扰的原因。借鉴传统MTI原理,针对警戒雷达同频干扰在方位扫描周期内慢速且规律性时变的特点,将MTI对消周期扩展为天线旋转周期,从而达到了良好的同频干扰对消效果。理论分析和仿真结果验证了这种旋转周期MTI对消技术在抗同频干扰方面的有效性。     

基于自适应对消的单通道相位编码同频异步干扰抑制

针对相位编码脉冲压缩雷达,利用多部雷达发射信号调相码间较好的正交性,结合自适应干扰对消原理,提出了一种基于自适应对消的单通道相位编码同频异步干扰抑制算法,在单通道情况下较好地抑制了同频异步干扰。并提出了同频异步干扰对消的结构,从统计特性与维纳霍夫方程两方面对算法进行性能分析。仿真表明,该算法在干信比38dB时脉压处理后主副比可达到20dB。     

各种体制与用途的雷达及系统

Y98-61502-64 9906369线性调幅连续波雷达的自适应对消技术研究=Studyof the adaptive cancelling technique in linear FMCWradar[会,英]/Zhang,X.C.& Zhen,S.C.//19976th International Symposium on Recent Advances in Mi-crowave Technology Proceedings.—64～67(UV)发射机与接收机间的有效隔离是限制 CW 雷达可用性和开发的关键问题。开发出一种线性 FMCW 雷达用的新型自适应对消系统,它把微波动态对消与中频动态对消结合起来,并利用了能解决干扰问题最有效的方法之一的 LMS 算法。分析了本系统的理论。做了仿真实验,给出了实验结果。参5     

毫米波连续波雷达载波泄漏对消

简述了连续波雷达载波泄漏的成因,我们把调频连续波雷达载波泄漏的矢量对消方案同传统的载波泄漏矢量对消方案相比后提出了利用数字信号处理方法实现毫米波调频连续波雷达载波泄漏的宽带多点对消方案及其实现框图,引入了获得载波泄漏信号参数的模板匹配方法,并且通过实际数据的仿真计算,获得了良好的对消效果.     

非协同目标连续波雷达测量技术

提出了解决非协同目的连续波雷达发射信号泄漏的各种方法。分析了微波、中频和视频泄漏对消技术，分析采用了正弦高超频、伪码调相信号形式抑制近区目标副瓣对远区目标检测的影响，提出了用脉冲雷达信号处理方法来处理连续波的信号。最后提出了一种准连续波雷达新体制。     

单旁瓣中频对消器的电路分析及实践

本文从电路实用观点出发,分析了单旁瓣对消器的连续波对消的性能、带通干扰的对消性能、对消器的过渡过程和对消环路的稳定性。介绍了一些实用电路要求及调试步序。初步进行了57.8兆赫及6兆赫二种中频对消器的实验,取得了比较满意的性能。     

一种密集假目标对相控阵自适应旁瓣对消的干扰方法研究

目前相控阵雷达硬件水平和信号处理能力不断提高,干扰方法的需求也日益凸显,因此对其干扰技术研究已成为一项研究热点。本文针对相控阵雷达自适应旁瓣对消,分析了间歇采样密集假目标干扰原理,以移频后的间歇采样干扰方法对自适应旁瓣对消进行干扰,并进行了仿真。结果表明,间歇采样密集假目标干扰方法频移后能完全掩盖真实目标。     

8mm连续波雷达微波对消技术

本文讨论了连续波雷达收发隔离问题的重要性,介绍了当前存在的解决收发隔离问题的方法。在8mm波段进行了实验,泄漏功率可被对消20～30dB以上,且能闭环跟踪泄漏信号的幅度和相位变化。由于测试仪器的限制,实际对消量还要大一些。     

脉冲多普勒雷达同频干扰研究

在雷达网络化探测和舰艇编队中,雷达之间的同频干扰是影响装备作战效能发挥的重要因素。针对脉冲多普勒体制雷达之间的同频干扰问题,提出了脉冲多普勒体制雷达同频干扰模型,并针对同频同步干扰和同频异步干扰两种情况进行仿真分析,仿真结果表明所提出的同频干扰模型能够有效地对脉冲多普勒雷达之间的同频干扰进行定量分析评估,同时表明脉冲多普勒雷达可通过严格时序控制,降低雷达之间的同频干扰。研究结果对脉冲多普勒雷达同频干扰分析和多雷达优化组网探测体系设计具有指导作用。     

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.     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

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。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.