两级GaAs单片功率放大器

本文报道了两级GaAs单片功率放大器的设计和制作,着重介绍了利用MESFET的小信号模型和直流负载特性设计MESFET在大信号状态下的最佳功率匹配的方法,该方法大大简化了放大器匹配电路的设计.制作在1.9×0.9mm GaAs外延片上的两级放大器,1dB带宽800MHz(670～1470MHz)频带内,最大小信号增益24dB,最大输出功率300mW.功率附加效率17.8%.     

一种60GHz LNA电路及其匹配网络的设计

从晶体管器件模型出发,对两种常用的LNA电路结构进行了分析,提出了一种60 GHz LNA电路结构.该电路使用级间电感匹配的方式,可以有效地提高电路的增益并降低噪声;同时,结合先进的生产工艺,对电路的匹配网络进行了设计和优化,充分利用直流偏置网络,简化输入输出匹配网络;使用最简单的电路结构,获得了较高的增益指标和较低的功耗.     

核磁共振功率放大器的设计与实现

简要介绍了核磁共振原理,分析了功率放大器的电路原理,设计并实现了一种应用于小型核磁共振系统的功率放大器.该功率放大器主要由两级放大电路组成,每级电路的核心器件分别为MRF475和MRF476,并围绕它们设计了相关的外围匹配网络.设计了一种门控电路以控制功率放大器的工作,该方法解决了目前现有的射频功率放大器稳定性能较差,噪声大的弊端.实验结果表明该功率放大器及其门控电路的设计是十分成功的.     

基于LTCC技术的Ku波段低噪声放大电路的设计

本文介绍了一款Ku波段低噪声放大电路的设计和优化技术，该电路集成于T／R组件（基于LTCC技术）前端，采用两个集成MMIC构成级连放大的结构形式。设计中，使用ADS软件对级间匹配进行优化设计，对芯片键合区设计补偿结构并使用HFSS软件对结构参数进行优化设计，以减少由键合丝的分布参数对传输特性的影响。     

L波段GaN大功率高效率准单片功率放大器

研制了一款基于NEDI 0.25μm GaN功率MMIC工艺的L波段大功率高效率准单片功率放大器。采用两级拓扑结构,以准单片形式实现。输入采用有耗匹配网络提高芯片的稳定性,级间和末级匹配均采用无耗纯电抗网络,其中末级匹配电路通过低损耗陶瓷电路实现。合理规划前级与末级间推动比,降低前级漏电流,减小末级匹配损耗,优化谐波匹配,实现大功率高效率设计。芯片在28V脉冲电压下工作,在1.2~1.4GHz范围内,实测输出功率大于49dBm,功率增益大于25dB,功率附加效率达到73%。管芯部分及输入匹配电路采用GaN功率MMIC工艺制作,输出匹配电路采用低损耗陶瓷片介质加工,两块电路键合一起总面积8.0mm×5.6mm。     

一种GaAs HBT微波功率放大器的设计

介绍了C波段宽带固态功率放大器的设计方法和实际测试结果。该放大器用于某雷达发射组件推动级,采用GaAs HBT器件,宽带匹配电路、直流偏置、负反馈设计。根据负载牵引分析,运用微波仿真软件对功率管的输入、输出阻抗匹配电路及其偏置电路进行优化仿真设计,增加电源控制电路保证可靠性,研制出了符合整机指标要求的放大器。     

2.4 GHz CMOS低噪声放大器的设计

设计了一个共源-共源共栅的两级低噪声放大器,并且在两级之间采用了串联谐振回路来提高电路的性能.该电路采用TSMC 0.18μm CMOS工艺,电源电压为1.8 V.仿真结果显示,在2.45 GHz的中心频率上,该电路能够提供26.92 dB的正向增益及很好的输入输出匹配,噪声系数为0.88 dB,功耗为14.49 mW,1dB压缩点为-9dBm.     

一种700 MHz频段的高线性驱动放大器MMIC

采用GaAsPHEMT工艺,设计了一种700 MHz频段的高线性驱动放大器MMIC.该放大器内部集成了带通复合匹配网络结构的宽带输入匹配电路,通过两种幅频特性相反的匹配网络进行组合,有效地拓展了应用带宽,提高了线性度和增益平坦度.放大电路采用两级放大结构,保证增益指标,引入稳定性设计以保证放大器工作的稳定性.偏置电路采用带负反馈系统的有源镜像结构,提高了驱动能力,使电路更加稳定.该放大器集成输出检波器,采用二极管检波器结构实现功率检波,具有结构简单、占用芯片面积小的优点.该放大器典型频点700 MHz处的输出三阶交调点为42.6 dBm,1 dB压缩点输出功率为27.6 dBm.通过调整片外输出匹配电路可满足700 MHz及其他频段的应用需求.     

1.8～2.8GHz低噪音放大器的仿真设计

利用pHEMT工艺设计了一个1.8～2.8GHz波段单片低噪声放大器电路.本设计中采用了具有低噪声、较高关联增益、pHEMT技术设计的ATT-58143晶体管,电路采用二级级联放大的结构形式,用微带电路实现输入输出和级间匹配,通过ADS软件提供的功能模块和优化环境对电路增益、噪声系数、驻波比和稳定系数等特性进行了研究.设计出一个增益大于20dB,噪声系数小于1.5dB,输入输出电压驻波比小于1.9,达到设计要求.     

一种用于RF LDMOS功率放大器的匹配技术

介绍了射频高功率放大器设计中RF LDMOS器件的预匹配和匹配技术.针对一款高功率RF LDMOS-FET,在器件法兰封装内为其设计了预匹配电路,并在PCB板级对其进行了输入输出匹配电路的设计,使其在工作频带内较好地匹配到50 Ω的系统参考阻抗上.仿真及测试结果表明,当频率为950 MHz时,该RF LDMOS功放的P...     

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）.