采用新型背腔的对数周期缝隙天线

针对超宽带雷达探测系统,提出了一款具有定向辐射性能的背腔式对数周期缝隙天线.该天线由一种具有超宽带匹配特性的渐变共面波导馈电.通过在缝隙天线背面设置谐振腔,使缝隙天线具有定向的辐射方向图.根据矩形谐振腔的特点,设计了一种新型结构的谐振腔,使得天线的驻波比(Voltage Standing Wave Ratio,VSWR)小于2.5.仿真与实测结果表明:天线在整个频带(0.9~5GHz)内具有稳定的定向辐射方向图,新型谐振腔和吸波材料的使用使天线最低工作频率可到0.9GHz,可使天线在整个频带内得到较高的天线增益.设计的天线适于应用在导航、探测以及超宽带(Ultra-wide Band,UWB)雷达等领域.     

一种具有陷波特性的Vivaldi天线设计

提出了一种具有陷波特性的新型超宽带Vivaldi天线。采用双Y巴伦实现了微带-槽线过渡,利用多阶阻抗变换器解决了宽带阻抗匹配问题。通过在微带线上添加狭缝,实现了对WLAN应用频段(5.125~5.825 GHz)的隔离,使该天线具有陷波特性。在仿真设计的基础上制作了实验模型,并对其进行了测量。实测结果表明:在超宽带UWB(Ultra Wide-Band)应用频带(3.1~10.6 GHz)范围内,除隔离频带(5.1~6.0 GHz)以外,该天线的驻波比VSWR≤2,辐射方向图定向性较好,且交叉极化较低,从而证明了该天线设计的实用性。     

一种小型超宽带微带天线

给出了一种小型化超宽带微带天线,该天线采用微带线对半圆形和矩形组成的阶梯状辐射单元进行馈电,基板背面为相似形缺陷地结构窗口。天线参数采用电磁仿真软件CST进行仿真和优化。所设计的小型化超宽带微带天线相对带宽达144.9%(2.15～13.47GHz),带内回波损耗均在-10dB以下,整个工作频段内天线的增益平均在4dB以上,天线的辐射方向图形状在频带内基本保持不变。该天线具有结构紧凑和形状简单的特点,易于加工和集成。最终实际制作了天线样品,并进行了测试,实测数据与仿真结果吻合良好。实验结果表明该微带天线具有良好的小型化和超宽带特性。     

一种结构简单且陷波特性易调节的超宽带天线

设计了一种具有陷波特性的超宽带(UWB)天线,由一个圆环形贴片和部分地板组成,通过在贴片上 刻蚀一个弧形槽可以在不改变天线尺寸的基础上实现阻带特性。利用HFSS 仿真软件对该天线进行了仿真设计,设 计结果表明天线能够在2. 8-10. 8GHz 频带内实现宽带特性,并在5. 1-6GHz 处形成阻带。在此基础上,加工和测量 了天线模型,实测结果表明天线在工作频带内具有良好的辐射方向图和稳定的增益,而且天线尺寸小、结构简单。 非常适合应用于超宽带系统。     

一种新颖的树状分形超宽带天线

该文设计一种新颖的树状分形超宽带天线,该天线采用梯形结构的有限接地面。增加树状分形结构的迭代次数和优化有限接地面的形状可以使天线获得良好的阻抗匹配,进而实现天线的超宽带性能。该天线的工作频带为4.2~17.5 GHz(相对带宽为122.6%),天线的电尺寸为0.350.35,可应用于C波段、X波段、Ku波段和超宽带(UWB)波段通信,具有广泛的应用前景。实测结果和仿真结果吻合,证明了该天线的有效性。     

具有陷波特性的超宽带分形缝隙天线

结合超宽带缝隙天线和分形结构的优点,设计了一种具有陷波特性的超宽带分形缝隙天线.选择E形缝隙结构,并在缝隙下边缘采用树状分形,构造半波长谐振结构,实现了天线的陷波功能,有效地避免了超宽带频带范围内的系统干扰.给出了天线设计的总体思路,通过理论分析和仿真测试,对天线的阻抗特性、增益进行了研究.结果表明,该陷波天线的阻抗频带为3 GHz ～12 GHz,在5 GHz～6.25 GHz频带内具有陷波特性.同时,分形结构的引入极大地缩小了天线的尺寸.     

应用于无线USB的小型超宽带阻带天线

设计了一种用于超宽带无线通信系统的小型化天线.该天线贴片尺寸为20 mm×15 mm×3mm,采用U形折叠结构和渐变结构相结合,可使天线具有超宽带特性.为了减小对无线局域网(WLAN)系统5GHz频带的干扰,天线采取了叉形谐振结构来实现对相应频带的抑制.采用仿真软件分析了该天线阻抗带宽和不同频点处的辐射方向图.仿真和实...     

超宽带Vivaldi阵列天线设计

为了满足超宽带系统对天线的需求,本文设计并制造了覆盖6～18GHz频带的超宽带Vival-di阵列天线,并采用微带渐变线功分器网络达到超宽带馈电与低损耗传输的目的。通过组阵与添加寄生单元进一步降低天线驻波,提高了阵列性能。仿真计算与实测结果表明该阵列天线在超宽频带内驻波小于2.1,并且具有优良的辐射特性。     

一款应用于微波探测脑中风的天线设计

针对目前微波探测脑中风成像系统中天线单元高增益、定向辐射、小型化等需求,设计了一款尺寸为0.28λ×0.28λ×0.17λ(其中λ 为天线最低工作频率所对应的工作波长)的平面定向单极子天线。该天线由渐变型辐射单元和开槽接地板组成,辐射单元由半椭圆形与阶梯矩形相结合构成,接地板开槽结构与辐射单元结构类似。为了增强天线的定向辐射特性,使用理想电导体(PEC)作为天线的反射板。结果表明,该天线S₁₁ <-10 dB 的工作频带为1.15~3.05 GHz,最大增益达到7.58 dB,在整个工作频带内天线的辐射方向图呈现定向辐射的特性。对天线进行加工测试,实测结果与仿真结果吻合良好。该天线可以应用于微波探测脑中风等领域。     

一种末端加载型300MHz/1GHz双频车载超宽带探地雷达天线设计

为满足高速铁路无损探测需兼顾低频探测深度与高频探测精度的要求,采用理论计算与软件仿真结合的方法,设计制作了一种双频带(300MHz/1 GHz)指数型TEM喇叭天线并对其进行了测量。所设计的指数型TEM喇叭天线采用末端加载和适当天线臂切削来实现此超宽带天线的双频带工作。仿真与实测结果表明,天线分别工作在中心为360MHz、带宽约为110MHz的低频带和中心为1 020MHz、带宽约为260MHz的高频带,相对带宽均大于20%。实测天线的接收信号保真度较高,拖尾持续时间短,满足设计要求。此外,这种双频带天线系统可减少雷达系统天线和采样盒等设备的使用数量,降低雷达系统的成本,有较好工程应用前景。     

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.