矩形波导窄边倾斜缝隙天线阵的设计

介绍了一种矩形波导窄边斜缝泰勒线阵设计的方法.简要阐述了矩形波导窄边缝隙天线阵列的相关理论,并使用HFSS软件对单个缝隙结构,无限阵列环境下缝隙单元的导纳参数进行数值仿真.然后按照仿真获得的等效谐振电导曲线,运用泰勒线元法综合求出非谐振式48元波导窄边缝隙线阵,并对整个线阵进行了仿真和实测.仿真和实测结果表明,该天线阵列具有低副瓣、宽带宽、高增益等特点,并且实测结果与仿真吻合良好.     

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。     

波导窄边缝隙阵天线的缝隙导纳的简易测量方法

正 (一)引言 串馈波导窄边缝隙阵天线是一种广泛应用的天线。波导缝隙电导与缝隙几何尺寸的关系是设计这种天线的基础,而缝隙导纳的频率特性则是分析天线频率特性所必不可少的依据。设计波导缝隙阵天线,虽有理论分析公式可以应用,但所得结果与实际情况还有出入;因此,设计之前,先测得波导缝隙的电导值。由于单个缝隙的电导值相当小,难以测准,加之缝隙之间又存在相互耦合,因此,人们都是测量多个(至少20个)缝隙的阵中的缝隙电导值。一般是采用测量S参量的方法,即测量波节点的移动,通过作图求得电导值。这种测量方法非常繁琐,而且精度也难保证。也有人采用行波功率法,但只能得到谐振频率上的电导值。至今尚未见到关于测量缝隙导纳的频率特性的简捷方     

宽频带膜片激励波导窄边非倾斜缝隙阵天线

文中提出一种新型宽频带低交叉极化的波导缝隙线阵设计，辐射单元是由波导内膜片激励的窄边非倾斜缝隙。线阵划分成多个子阵，并由功分器馈电。设计、加工了一个16单元X波段的均匀直线波导缝隙阵，测试得到7．2％阻抗带宽（VSWR≤1．5），天线辐射方向图最高副瓣电平低于-11．8dB，并且具有低于-39dB的交叉极化特性。     

X波段缝隙波导阵列天线

本文主要介绍窄边缝隙波导阵列天线的设计方法,最重要的是确定所需孔径分布(它决定副瓣电平)的缝隙电导。然后由实验得到缝隙的实际参数。为了验证设计方法,在X波段加工了70个缝隙的波导阵列,同时设计了一个二维波导平板阵,作了较全面的试验,获得了比较满意的结果。     

波导窄边缝隙阵列天线的分析与设计

波导窄边缝隙阵列天线由于效率高、功率容量大、稳定性好及副瓣电平低等特性,在雷达体制上使用广泛。对于单一波导窄边缝的隙线阵,根据设计指标,首先分析其理论模型并给定理想的设计参数,再利用Ansoft公司的HFSS软件的参数扫描及优化功能,通过局部调整设计参数就可以方便地得到缝隙的谐振结构。利用这种设计方法可以快速得出所需要的低副瓣窄边波导缝隙阵列天线。     

波导窄边斜缝行波阵列天线设计

为了快速设计波导窄边斜缝行波阵列天线,采用理论计算结合软件仿真的方法。利用电磁仿真软件HFSS模拟实验过程,得到裂缝电导函数。初始设计完成后,比较仿真结果口径分布和理论口径分布的差异,微调裂缝尺寸参数使天线口面幅度逼近设计值。设计了一个47阵元行波线阵,并采用两根波导对称放置抑制交叉极化。Taylor综合副瓣值为-30 dB,仿真得到的最大副瓣值为-24.8 dB,波瓣宽度为2.2°,增益为24.6 dB。     

一种新颖的圆极化波导阵列天线设计

介绍了一种新型的Ku波段赋形圆极化波导缝隙阵列天线设计,采用矩形波导宽边纵向直缝隙耦合馈电四脊方形开口波导实现了波导天线的圆极化工作;采用波导窄边耦合器形式的功分器和配相波导组成的馈电网络,控制各线阵的幅度和相位,利用幅度和相位加权的方法实现了圆极化波导天线的波束赋形工作。基于项目需求设计、加工了一套24×16单元天线阵列,测试结果表明,该天线在3%的频段内轴向轴比优于3.0dB、驻波比优于1.6、赋形波束区域覆盖了-40°~0°的范围,满足了项目的指标要求。     

一种Ka 波段对称四波束波导缝隙行波阵列天线的设计

本文给出了一种Ka 波段对称四波束波导缝隙行波阵列天线的设计方法。该设计对经典行波阵理论进行了改进 和创新,提出将驻波阵的电流幅度分布理论应用于行波阵,推导出多波束波导缝隙的电场分布方程,实现了波导缝 隙阵列天线对称四波束配置,并具备共口径、高增益、低副瓣等优点,满足多普勒测速雷达对天线的要求。HFSS 软件仿真测量结果验证了该设计的正确性。     

低成本宽角相频扫阵列研究

大角度的两维相频扫阵列具有更广阔的空域覆盖能力。本文,通过对普通直波导的改进,设计了一种新型波导慢波线窄边缝隙线阵,大大增加了波导在固定频带内的频扫范围。该阵列在10%的带宽内,具有方位相扫±45°、俯仰频扫大于20°的扫描能力。通过理论仿真与实测结果可以验证,该低成本宽角相频扫阵列具备可实现性,具有很高的工程应用价值。改进后的波导缝隙阵为进一步提升雷达天线的空域覆盖能力奠定基础。     

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.     

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.     

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.     

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.