应用MATLAB协同HFSS设计波导缝隙天线

电磁仿真软件HFSS以其高精度,高可靠性在电磁仿真设计中得到了广泛的应用。而对于复杂天线的模型,没有很好的方法简化建模操作,需要花费大量的设计时间。将HFSS提供的VBScript脚本语言功能作为接口,利用MATLAB调用控制HFSS,从而协同HFSS建立模型,达到快速建模的目的。提出了一套波导缝隙阵天线的设计方法,设计了一个波导缝隙阵天线,运用MATLAB协同HFSS建立天线模型,并进行仿真分析。结果验证了天线设计方法的准确性,以及运用MATLAB调用HFSS建模的可行性。     

应用MATLAB协同HFSS设计波导缝隙天线

电磁仿真软件HFSS以其高精度,高可靠性在电磁仿真设计中得到了广泛的应用.而对于复杂天线的模型,没有很好的方法简化建模操作,需要花费大量的设计时间.将HFSS提供的VBScript脚本语言功能作为接口,利用MATLAB调用控制HFSS,从而协同HFSS建立模型,达到快速建模的目的.提出了一套波导缝隙阵天线的设计方法,设计了一个波导缝隙阵天线,运用MATLAB协同HFSS建立天线模型,并进行仿真分析.结果验证了天线设计方法的准确性,以及运用MATLAB调用HFSS建模的可行性.     

K波段低副瓣波导缝隙驻波阵设计

本文设计了一种 K 频段低副瓣波导缝隙驻波阵天线,给出了实现低副瓣的方法。设计副瓣电平为-27dB,缝隙幅度分布按-30dB 泰勒分布计算,结合高频仿真软件 Ansoft HFSS 对各缝隙归一化导纳进行计算,建立仿真模型并优化天线各参数。依据设计结果加工实物并测试其方向图及增益。测试结果表明,该天线在工作频带内波束宽度约 3°,副瓣电平小于-27dB,工作频带内增益大于 30.8dB,仿真结果与实测结果相符,设计满足指标要求。     

一种抑制波导窄边缝隙阵列天线交叉极化的方法

为了抑制波导窄边缝隙阵列天线交叉极化电平,采用一种在波导外壁开非倾斜缝隙、在波导内壁开倾斜缝隙的方法。利用电磁仿真软件HFSS进行仿真,得到孤立缝隙与阵中单个缝隙的电导函数。设计了一个47单元X波段波导窄边缝隙均匀直线阵列,与常规缝隙阵列相比,天线交叉极化电平降低了6.8 dB。     

一种波导窄边裂缝天线缝隙倾角的改进方法

为减小波导窄边裂缝天线缝隙间互耦对天线性能的影响, 实现低副瓣的设计, 提出了一种倾角波动分布的设计方法.天线电流分布选用泰勒分布, 利用HFSS软件确定缝隙倾角初值, 在此基础上得到波动分布的倾斜角度, 并通过遗传算法对缝隙倾角进行优化.使用Matlab与HFSS软件联合仿真, 省略了建模、设置参数等大量操作, 提高了设计效率.基于此, 设计了一款长度为1.2 m的X波段波导窄边裂缝天线, 仿真发现副瓣电平比传统设计方法低2.17 dB, 加工了天线实物并进行了测试, 天线实测增益和副瓣电平分别为20.9 dBi和-28.7 dB, 验证了方法的有效性.     

星载Ku波段波导缝隙天线的缝隙特性分析

在星载Ku波段谐振式波导缝隙阵列天线设计中,由于结构空间的限制,采用半高非标准波导。考虑到半高波导中更容易产生高次模影响的特点,以及设计成本和效率问题,将基于有限元法的高频电磁仿真软件Ansoft HFSS与Fortran编程相结合应用于该类天线的设计。采用HFSS研究并描述了宽边纵向辐射缝隙和中心倾斜耦合缝隙的特性,结合Elliott提出的经典平面缝隙阵设计理论,用Fortran编程设计了阵元数为80(8×10)的波导缝隙阵列天线实验件,并用HFSS仿真优化了天线阵整体的性能。对实物天线进行了近场测试,结果表明:天线的E面和H面副瓣电平分别是-29dB和-27.5dB,1.3以下驻波带宽为340MHz,与仿真结果基本吻合。良好的测试结果验证了用HFSS获取缝隙特性曲线的正确性及设计方法的有效性,为后期大型阵列设计提供了一种有效的方法。     

一种新型垂直极化同轴波导缝隙天线

结合波导缝隙和同轴线结构,提出了一种新型同轴波导缝隙结构实现天线小型化。首先,分析了同轴波导缝隙天线内金属摆线上的电流分布,改进了缝隙形式和摆线设计;然后,利用HFSS软件建立不同缝隙数目的同轴波导缝隙天线模型进行仿真,对比分析驻波带宽和方向图带宽;最后,建立不同缝隙数目的同轴波导缝隙天线有限阵列,对比分析阵列中天线增益和效率。     

新型Ku波段基片集成波导缝隙阵列天线设计

介绍了基片集成波导缝隙天线的相关理论,以及宽边基片集成波导缝隙驻波阵的设计方法。首先,根据指标要求,利用HFSS电磁仿真软件来获取缝隙初始导纳参数;然后,使用Matlab软件进行数据拟合;最终,得到缝隙电导与缝隙偏置的数学函数。采用该方法设计了中心频率为15. 9 GHz 的4 元等幅同相的驻波直线阵,仿真得到在15. 8 GHz ~16 GHz 频段内驻波比小于1. 88。     

基于MATLAB和HFSS的叠层微带天线优化设计

提出了基于MATLAB和HFSS协同仿真优化设计天线的思路,并以叠层微带天线为例开发了相应的设计软件。利用MATLAB GUI编写了软件的操作界面,通过输入天线的技术指标,进行天线各参数的计算,利用生成的VBScript脚本文件调用HFSS进行快速建模仿真,并通过调用外部优化算法进行天线的最优化设计。该软件提高了叠层微带天线的设计效率,为天线的教学与科研工作提供了有效的辅助工具。     

宽带单脊波导缝隙天线的设计

根据传输线方程推导了单脊波导辐射缝隙有源导纳的计算公式,结合三维电磁仿真软件HFSS提取了天线阵列中辐射缝隙的有源电导,设计了一个8元单脊波导缝隙线阵,实测结果表明,副瓣为-23.61dB,VSWR≤2时的相对带宽为8%,约为矩形波导缝隙天线的2倍。     

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-