用于无线电监测的超宽带喇叭天线的研制

研制了一款用于微波频段频谱监测以及测向的,可以覆盖900MHz～11GHz的高增益超宽带喇叭天线。此款天线采用在传统喇叭天线腔体中加入一对渐变的寄生脊的方法,优化馈电部分同轴到双脊波导的转换,实现了同轴到波导的宽带匹配。最终天线实现了数十倍频程内驻波比小于2,增益在8～13dB之间,并且具有稳定的辐射方向图。     

同轴馈源性能改善的方法

同轴馈源是用于反射面天线双频共用馈源的一种重要形式,其内导体为工作在高频段的圆波导馈源,同轴区域为工作在低频段的同轴馈源.如何提高同轴区域低频段馈源的性能,是这种馈源研究的主要内容.采用电磁仿真和实验的方法研究了同轴馈源辐射方向图等化的技术途径,测试结果与仿真结果吻合,并达到了预期的设计指标,验证了技术途径的有效性.     

一种共面波导馈电的双陷波渐变槽天线

为了滤除WIMAX(3.3～3.8 GHz)和WLAN(5.125～5.825 GHz)窄带信号对超宽带系统的干扰,该文提出一款共面波导馈电的小型化双陷波渐变槽天线。共面波导结构可以有效地扩展天线的带宽,实现对整个UWB(3.1～10.6 GHz)频段的全覆盖。通过在天线的馈线上开L型缝隙和在辐射贴片上开一对E字型缝隙的方法,有效实现了在3.15～3.97 GHz和4.94～6.05 GHz频段的双陷波特性,能够抑制WIMAX和WLAN对超宽带系统的干扰。该天线结构简单紧凑,尺寸非常小,仅为40 mm×18 mm×0.813 mm。仿真和实测结果表明该天线在超宽带波段内具有良好的陷波特性、增益特性,可以应用于小型化超宽带系统中。文中方法对于陷波渐变槽天线的研究具有一定的借鉴意义。     

MEMS铜基微同轴传输线性能仿真及测试

研究了一种新型的MEMS超宽带铜基微同轴传输系统。设计了特性阻抗为50Ω铜基微同轴传输线结构,其仿真电压驻波比(VSWR)在DC～110 GHz内低于1.15。且设计了可用于探针台测试和芯片金丝键合的地-信号-地(GSG)转接结构,仿真插入损耗低于0.1 dB。采用该微同轴结构和GSG转接结构设计了用于探针台测试的直通-反射-传输线(TRL)校准套件,利用薄膜工艺加工得到了铜基微同轴传输线及校准件实物,通过实验测试得到该微同轴传输线DC～40 GHz最大插入损耗为0.35 dB/cm,通过仿真拟合推算其110 GHz下的插入损耗约为0.65 dB/cm,该插入损耗性能显著优于平面印刷传输线,同时,该微同轴传输线的体积远小于波导传输结构,可以用于研制小型化、高性能、高集成密度微波/毫米波系统。     

S/X双频共用同轴馈源

提出了一种用于射电望远镜50m天线、S/X双频共用且对S、X双频段具有不同照射角的同轴馈源设计方法,S、X两个频段的相对工作频带宽度均为20%,S频段为同轴馈源,内导体为圆波导馈源工作在X频段。采用电磁仿真和实验的方法研究了同轴馈源辐射方向图-10dB点波束宽度的调整方法和减小同轴馈源电压驻波比和轴比的技术途径。对同轴馈源方向图、电压驻波比和轴比进行了测试,测试结果与电磁仿真结果比较吻合。     

8-18GHz同轴-波导转换器的分析与设计

同轴-波导转换器是微波系统中非常重要的元器件.基于脊波导和波导阶梯对导播系统中电磁波传播性能的影响,本文探讨了这两种结构应用在8-18GHz的宽带同轴-波导转换器设计中的情况.通过同轴-脊波导-矩形波导转换,并在脊波导上加载阶梯,很好地改善了阻抗匹配效果,提高了同轴-波导转换器的传输性能.仿真结果证明脊波导和波导阶梯在设计同轴-波导转换器中的有效性,在8-18GHz的倍频程带宽内驻波小于1.22,产生的高次模非常小.     

基于脊波导结构的太赫兹超宽带双工器设计

在射电天文领域,为了实现更宽频带内多谱线同时观测任务,要求太赫兹超导相干接收机向更宽带方向发展。针对下一代太赫兹超宽带接收机的应用需求,提出了一种频段覆盖180~ 420 GHz(相对带宽达87%)的超宽带脊波导双工器设计,主要包括：180~300 GHz频段和320~420 GHz频段宽带脊波导滤波器设计与变换;超宽带太赫兹多级耦合型脊波导双工器优化设计。仿真结果表明该结构能够在180~300 GHz和320~420 GHz频段双工工作,回波损耗整体优于15 dB,通道间隔离度达20 dB以上。     

一种性能改进了的大张角四脊型超宽带馈源的研制

超宽带馈源在通信和射电天文等领域有着极高的应用价值。四脊喇叭作为宽带馈源的一种重要形式,存在着反射损耗性能较差,方向图随频率波动严重,照明张角难以拓展等诸多缺陷。本文基于国际上已有的研究基础,设计了一款工作于1.2~6.8 GHz的双极化大张角四脊型超宽带馈源。该设计方案对脊片部件采用了"削出倒角"、"厚度赋形"和"脊片外延"的改进措施,显著改善了馈源在低频段的反射损耗性能,同时也拓展了照明张角,使其能够更好地应用在大张角主焦照明的场合。实测结果显示出,该超宽带馈源的带宽和反射损耗性能均略优于国外样机。在边缘照明角为68°的大张角情况下,该馈源依然可以在1.2~6.8 GHz的带宽(相对带宽5.67:1)内达到低于-10 dB的反射损耗,其中在2.5~5.3 GHz内的反射损耗低于-15 dB。而且,该馈源在E面和D面的-12 dB边缘照明角随频率的波动小于20°。     

无线电设备、电信设备

TN811,TN8142005040705一种新型同轴TEM-圆波导TE11模式变换器/刘庆想,袁成卫(西南交通大学理学院)//强激光与粒子束.―2004,16(11).―1421～1424.提出了一种新型同轴插板式模式变换器,可以实现同轴TEM到圆波导TE11模式的变换。介绍了这种模式变换器的工作原理:即通过在同轴波导中沿轴向插入金属板,将同轴TEM模变换成扇形截面波导TE11模,进而利用不同扇形截面波导中的相移改变电场分布的轴对称性,在同轴波导中形成同轴TE11模,最后将同轴TE11模转换为圆波导TE11模式。基于这一原理设计了一个中心频率为3.8GHz的同轴TEM-圆波导TE…     

W波段低电压宽带过模矩形同轴曲折波导行波管的研究（英文）

提出了一种具有高频率、宽频带和低电压特点的矩形同轴曲折波导慢波结构,所提出的矩形同轴曲折波导工作于过模状态,工作频率较高,同时具有不错的传输特性。设计了一种宽带的双脊加载的波导-同轴转换器,其带宽可以覆盖矩形同轴曲折波导行波管的整个工作频带。所设计的矩形同轴曲折波导行波管工作电压和电流分别为3230 V和150 mA,慢波结构长度为32 mm,PIC仿真结果表明,在76～110 GHz频率范围内,其输出功率超过13.7W,在108GHz频点,输出功率达到最大值,约为27.4W,对应的射频效率为5.65%。     

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.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

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.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

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.     

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.