5G天线对典型强电磁脉冲响应的对比分析

针对强电磁脉冲环境对5G通信系统的威胁,以5G天线为例,研究了典型电磁脉冲经天线口面耦合进入天线端口的电磁脉冲能量大小。利用电磁仿真软件分析了微带天线单元在高空核爆电磁脉冲、高功率微波以及超宽带电磁脉冲环境下天线馈电端口处感应的瞬态电压的时域和频域特性。仿真结果表明:高功率微波和超宽带电磁脉冲在天线单元馈电端口的感应电压较大,极易干扰甚至毁伤5G通信系统的射频后端。     

贯穿设备屏蔽层线缆电磁脉冲响应研究

提出了一种获取电子设备壳体屏蔽层外接线缆电磁脉冲耦合响应的计算方法。首先,以壳体屏蔽层为分割点,将贯穿线缆分为内外两部分,根据基本传输线理论和戴维南等效原理,得到内外两段线缆的等效电路模型。然后,利用Agrawal散射电压模型分析了外等效电路的端口负载频域响应,并根据该负载响应得出了内部线缆等效电路的端口负载频域响应。最后,以高空核爆电磁脉冲的IEC标准波形为计算波形,通过傅里叶变换方法求解了内部端口上的时域响应,并分析了线缆几何参数和终端负载对响应波形的影响。     

一种高隔离低交叉极化等相位中心双极化开槽天线设计

设计了一种高隔离度低交叉极化等相位中心双极化开槽天线,通过对馈电巴伦进行改进设计,解决了两个正交极化开槽天线交叉排布时相位中心不一致难题。由于双极化天线的辐射和馈电部分完全对称,该天线可获得良好的端口隔离度和低交叉极化特性。仿真结果表明,与常规双极化开槽天线相比,该双极化天线的交叉极化可改善20 dB,90%频带内的隔离度提高15 dB 以上,并且该双极化开槽天线在数倍频程带宽内具有良好的匹配和辐射特性,能实现大角度二维扫描,适用于未来宽带多极化相控阵天线系统。     

一种新型高效率双极化背腔阵列天线

针对卫星通信系统对双极化天线的隔离度、口径效率及端口隔离度等指标提出的要求,设计了一种高效率双极化背腔阵列天线,天线辐射单元采用方口喇叭,辐射效率高,采用空气悬置带线馈电网络大大降低了馈电损耗,采用反相馈电技术改善了天线的交叉极化隔离度。重点讨论了2×2子阵的口径效率、交叉极化和端口隔离。利用仿真软件进行了优化仿真分析,在此基础上研制了16×32阵列样件,对其电性能进行了测量,测试结果表明,此双极化阵列天线具有辐射效率高、交叉极化电平低、端口隔离度高的特点。     

宽频带高隔离度基站天线的设计

设计了一种适用于基站天线的宽频带高隔离度双极化对称阵子天线单元,利用电磁仿真软件HFSS对该基站天线单元的电特性进行仿真分析。仿真结果表明,天线在698～960 MHz频段内电压驻波比VSWR〈1.35,端口隔离度〉41 dB,且具有良好的小型化特性。该研究为低频段宽频带移动通信基站天线设计,提供了参考     

一种宽带高隔离度双极化微带天线的设计

设计了一种宽带高隔离度的双极化微带天线,天线的两个馈电端口分别采用了H型口径耦合和容性加载H型口径耦合,在展宽带宽的同时提高了双端口隔离度,同时利用反射板使天线获得较高增益。HFSS仿真和实测结果表明天线双极化端口的阻抗带宽（VSWR〈2）达40%,增益达到8 dB以上,端口隔离度大于33 dB,该天线可被广泛应用于双极化天线阵系统中。     

微型化光纤传输电磁脉冲传感器研究

研制了一套用于小空间电磁脉冲测试的光纤传输电磁脉冲电场传感器。通过电磁仿真软件CST2011,研究了天线结构对被测场影响,并讨论了天线结构、负载阻抗与响应带宽和灵敏度之间的关系,确定了主要设计参数。研制的微型化传感器采用屏蔽结构与偶极子天线的一体化设计,有效减小了天线与电光转换部分的体积和对被测场的扰动,适用于核电磁脉冲和雷电电磁脉冲的测量。传感器采用对称结构,满足自由空间场测量的需要,为电磁脉冲测量和电磁脉冲场标准装置的校准提供了新的手段。     

孔缝腔体内传输线负载上最大感应电流的研究

应用多端口网络理论,把孔缝屏蔽腔和腔内传输线一起等效成多天线系统,基于天线的互易定理,提出了快速预测孔缝屏蔽腔内多导体传输线负载上的最大感应电流的方法.由于避免了孔缝屏蔽腔内传输线负载上感应电流的直接全波分析,计算效率显著提高.文中计算了矩形屏蔽机箱上开孔尺寸与形状、机箱大小、传输线在机箱内位置等参数改变下屏蔽机箱内传输线负载上的最大感应电流响应.与直接全波仿真结果比较,验证了方法的有效性.     

基于矩量法对导体板上单极天线特性研究

利用矩量法对有限大导体板上单极天线的阻抗特性进行了研究。基于Pocklington积分方程和Galerkin法，采用分域基正弦函数展开模式，得出了有限尺寸导体板上单极天线的电流分布和输入阻抗，并对单极天线在不同长度及不同导体板上的情况进行了研究。结果表明，单极天线的长度及导体板的形状及大小在一定程度上影响了单极天线的特性。     

阵列天线互耦的矩量法分析

文中采用矩量法分析无限大理想导体板上的偶极子天线.利用分段正弦基函数Galerkin法推导出阵列天线偶极子单元的阻抗及电场分布的公式.采用Matlab编程计算了中心单元馈电,其他单元接匹配负载情况下中心偶极子天线在阵中的方向图.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

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.