微带串馈天线阵的理论分析和仿真设计

论述了微带天线的基本理论、经典分析方法、天线单元的馈电方法以及微带阵列天线的形式、特性及馈电网络,从毫米波天线单元入手,研究了16元矩形微带贴片天线阵的设计方法,并给出了仿真结果,与理论计算值相符。     

K 波段串馈微带贴片天线设计分析

本文介绍了矩形微带天线的特点、原理以及设计方法,设计了1?16 元矩形贴片组成的串馈天线阵,通过对各微带单元进行同相馈电,同时在馈电网络中利用阻抗变换对天线的阻抗进行匹配,并运用天线仿真软件Ansoft HFSS对此天线进行了仿真分析,获得了较好的辐射特性。     

一种新型混合馈电24GHz车载雷达阵列天线设计

针对阵列天线馈电网络比较复杂的问题,设计了一款24 GHz新型串并馈结合的微带天线阵,并进行了理论研究和仿真测试。该天线阵采用了串并联混合馈电网络,天线子阵和馈电网络的电流分布均采用了切比雪夫分布,有效抑制了旁瓣电平。同时将馈电网络与串馈天线子阵直接连接在一起,达到了小型化的目的,并减小了馈电网络的损耗。仿真结果表明:天线阵的增益可达到21.7 dBi,在中心频率24.1 GHz附近,E面和H面的副瓣电平分别为-20.3 dB 和-26.2 dB。该天线阵体积小,性能可靠,可用于24 GHz汽车防撞雷达。     

Ku波段DBS微带接收天线阵

介绍了一种Ku波段接收直播卫星电视信号的平面型天线。该平面型天线是一种由矩形微带贴片及其位于同一平面的微带线分支馈电网络组成的平面微带天线阵。采用商用计算软件对此天线阵进行仿真设计，并制作了由1024个微带矩形贴片组成的阵列天线，对其参数进行TN试，表明计算与测试结果基本吻合。最后用此天线接收了若干卫星上的Ku波段电视信号，效果良好。     

C波段高增益圆极化微带天线阵的研制

论述了圆极化微带天线阵的设计方法。以工作频率为5.8GHz,32单元圆极化微带天线阵为研究对象,设计出了与馈电网络为一体、具有圆极化特性的微带天线阵,从而解决了圆极化微带天线阵馈电网络较为复杂、工程实现较为困难这一问题。实验结果表明该天线阵具有良好的圆极化特性,进而说明了该方法是有效可行的。     

8mm边馈式微带天线阵研究

本文对８ｍｍ边馈式微带天线阵进行了理论和实验研究，给出了并馈矩形贴片阵元和馈电网络的设计方法，采用新型的波导－微带正变型转换接头，研制出６４、１２８和２５６单元的三种边馈式毫米波微带天线阵，其性能指标已达到国外同样水平     

8mm边馈式微带天线阵研究

本文对８ｍｍ边馈式微带天线阵进行了理论和实验研究，给出了并馈矩形贴片阵元和馈电网络的设计方法，采用新型的波导－微带正交型转换接头，研制出６４、１２８和２５６单元的三种边馈式毫米波微带天线阵，其性能指标已达到国外同样水平。     

X波段微带天线阵的新型高效馈电方式研究

提出了一种采用波导缝隙和微带线共同给X波段微带贴片天线阵馈电的新型方式.用NFDTD对这种面阵进行数值仿真和设计.已制作出的天线阵的实测结果表明其效率可达68.5%.     

共口径波束可控双缝隙耦合微带天线阵设计

针对波束倾角可控天线的小型化和低成本,设计了宽频带双缝隙耦合矩形微带天线单元,组成1×8元线阵,采用2套基于Wilkinson不等功分器的馈电网络实现切比雪夫的幅度分布。具有不同相位差的2套馈电网络,通过不同的缝隙耦合对同一微带单元口径面馈电,分别形成了2种倾角的波束。仿真结果表明,共口径双缝隙耦合微带天线阵实现了90°和75°两种波束倾角的可控切换,是一种体积小、造价低的方向图可重构天线。     

一种X波段正交极化偶极子天线阵设计

为解决X波段机载雷达变极化速度较慢的问题,设计了一种可实现脉间变极化的偶极子天线阵.该天线阵采用正交排列薄片电偶极子阵元,并加装垂直贴片和反射板,通过同轴线耦合巴伦进行馈电.利用改造后的阵元组成了一个4×4的16元矩形栅格、矩形边界均匀平面正交极化天线阵,利用射频开关控制馈电线路实现快速变极化,通过高频结构仿真(HFSS)软件对其进行参数优化和建模仿真,结果显示,该天线阵具有较低的驻波比和副瓣电平以及较高的天线增益,可以作为机载正交极化相控阵雷达天线的参考设计,或用作正交极化阵列天线的子阵.     

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.     

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.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

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.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

中国建立EB级存储实验室,致力云计算应用(英文)

正With the support of 863 programs,Sugon Information Industry Co.,Ltd.,set up a dawning EB-class storage laboratory to address massive data storage requirements and largescale cloud computing demonstration applications.The Dawning EB-class cloud storage system adopts advanced fault-tolerant architecture,efficient data fault-tolerant algorithms with user authentication and data encryption policies to deal with the"lost""wrong"and"stolen"problems of data for ensuring the reliability and safety of the EB-class storage system in the public network application environments.The Dawning EB-class Storage Laboratory taking advan-