含有寄生单元的倒F天线分析与设计

提出了在普通倒F天线的两侧和底部同时添加寄生单元的改进倒F天线,该天线与普通的倒F天线相比有更宽的带宽.设计了一个工作于中心频率1.2GHz的改进倒F天线.对该天线的电气特性进行了仿真计算,并对天线主要结构参数对谐振频点和阻抗带宽的影响进行了详细分析.该天线相对带宽达到了33%(VSWR<2),约为普通倒F天线阻抗带宽的4倍,有效地展宽了传统倒F天线的工作带宽,在宽带通信系统中有较好的应用前景.     

一种适用于蓝牙的折叠PIFA天线的设计和分析

介绍了传统印制倒F型天线的工作原理和结构特性,详细分析了影响天线阻抗的因素。以一款支持蓝牙功能的GSM手机为例,通过ANSOFT公司的软件HFSS 10.0进行仿真,设计了一款体积小、性能好的蓝牙天线。该天线工作于2.4~2.483 GHz频段、尺寸只有16 mm×4.5 mm,10 dB阻抗带宽为5%。改善后的PIFA天线成本低、结构紧凑、馈电方便,同时设计简洁、灵活,完全适于蓝牙系统应用。     

新型WLAN平面倒F双频天线的设计

提出了一种新型的应用于2.4/5GHz蓝牙和无线局域网的双频内置平面倒F天线。该天线结构紧凑,可以方便地植入无线通信设备中,有较强的实用性。通过加载F形槽和阶梯形槽使天线能够满足无线局域网中小型化双频天线的技术要求。天线在蓝牙频段阻抗带宽达到300MHz(2.21~2.51GHz),在无线局域网频段阻抗带宽达到1070MHz(4.95~6.02GHz),辐射方向图表明该天线全向性能较好,增益在3.1~6.7dBi范围内。     

新型共面波导馈电超宽带单极子天线设计

提出了一种新型的超宽带单极子天线,该天线将经典圆形单极子的下半圆用两个倒梯形替代,有效减小了天线的体积,利用电磁场仿真软件Ansoft HFSS对该天线进行了仿真优化。结果表明,该天线的阻抗带宽为2.48~15.23 GHz,覆盖了超宽带通信系统的带宽。该天线在2.48~15.23 GHz带宽内的S11≤–10 d B,VSWR≤2,具有比较稳定的辐射特性,符合超宽带通信系统的要求。     

一款基于HFSS仿真的倒F蛇型印制天线

设计了一种用于2.4 GHz智能无线传感器的倒F蛇型天线,.使用HFSS仿真和设计,根据优化后的天线模型参数,最终设计集成在无线传感器印制电路板上印制天线,使天线可达到最佳的效果.该天线的仿真和实测结果表明,在2.45 GHz的中心工作频率下,回波损耗小于-12dB,带宽约为100 MHz,阻抗50.58+j0.55,满足了IEEE 802.15.4协议的要求.     

一种多频带印刷单极子天线的设计

提出了一种小型化的用于WLAN/WiMax通信系统的多频带印刷单极子天线。通过改进双“G”形的振子结构,使天线能在2.4 GHz,3.5 GHz和5.5 GHz谐振,实现2.4/5.2/5.8 GHz WLAN 和3.5/5.5 GHz WiMax频带的覆盖。对加工后的天线模型测试表明,天线在工作频带内具有较宽的阻抗带宽和较好的辐射特性。因此,该天线可以应用在多频带无线通信系统中。     

基于HFSS多层宽带微带天线仿真设计

采用HFSS10电磁场仿真软件设计和仿真了一种宽频带多层微带贴片天线.天线采用双辐射贴片系统,同时利用正方形金属电容片补偿由于馈电探针引入的电感,从而获得了比较宽的工作带宽.该天线仿真的驻波比VSWR≤2时的阻抗带宽达到了25%,覆盖了1.4GHz～1.8GHz的频率范围.且仿真结果表明该天线还具备了良好的宽波束和高增益特性,天线的半功率波束宽度在100度左右,在两个谐振频率点1.45GHz和1.75GHz处的最高增益分别为9dB和10dB,与理论计算的值有很好的一致性.结果也说明了HFSS软件的可靠性和高效性.     

一种适用于GSM DCS和ISM频段的PIFA天线

移动通信业务的多样化要求多种业务共用一副天线,以节省终端内的有限空间。在平面倒F天线(PIFA)的基础上加载一种新型的缝隙结构,得到一种适用于GSM900、DCS1800和ISMWLAN2.4GHz三个频段的小型宽带移动终端天线。仿真结果表明,该天线在三个频段上的相对阻抗带宽分别达到6.5%、7.5%和3.4%,尤其是在GSM900MHz频段的阻抗带宽比其他同类型天线展宽1倍。该天线具有较好的频率特性和辐射特性,完全适合多频移动通信终端应用。     

平面三角形单极子天线展宽带宽研究

介绍了一种利用变形地板来展宽平面三角形单极子天线带宽的方法。通过在天线地板上刻蚀对称的变型L型缝隙,天线的阻抗带宽增加到2.5~10.8 GHz,带内驻波比(VSWR)＜2。对比没有刻蚀缝隙的天线,不仅工作频带得到展宽,而且保持了较好的辐射性能。测量和仿真结果表明,天线的工作频带能够覆盖整个超宽带(UWB)范围。     

一种改进型微带贴片八木天线的设计

设计了一种宽带微带贴片八木天线.通过采用正方形贴片形状、附加寄生贴片等方法,获得了较大的相对阻抗带宽和较好的方向性.该天线工作频率为12 GHz,三维电磁仿真软件Ansoft HFSS 仿真结果表明:这种改进型天线在其它参数不变的情况下,其相对阻抗带宽达到27.5％(VSWR≤2),实现了天线频带的超宽性,满足了某项目...     

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.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.