共查询到20条相似文献,搜索用时 78 毫秒
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针对无线通信系统对超宽带(Ultra-Wideband,UWB)天线小型化的需求,提出了一种同轴馈电的UWB天线,由常规的椭圆单极子天线演变而成.为了获得UWB特性,天线的辐射单元由7个完全相同的椭圆单极子合理组合而成.该天线印刷在相对介电常数为4.4、 厚度为1.6 mm的FR4介质板上,并通过同轴进行馈电,天线的结... 相似文献
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超短波印刷天线的研究 总被引:4,自引:1,他引:4
本文讨论了一种新型全向宽频带超短波印刷天线。利用设计天线辐射体的外形尺寸和债电处接地体的阶梯渐变结构来改变分布电容,达到阻杭匹配的目的。在50MHZ频带内驻波比小于1.2,在使用频段15MHZ频带内驻波比小于1.1。采用十字形馈电方式,利用两直立板状辐射体形成腔体传输水平极化分量,两极板构成直立天线对,使天线的方向图为半球状。采用这种设计方法可减小天线的尺寸。 相似文献
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该文设计了一种基于直角反射器的宽带高增益天线。天线结构包括八元印刷偶极子阵、一分八并联馈电网络、直角反射器。平行双线形式馈电网络实现各偶极子单元平衡馈电的同时具有阻抗变换作用,从而保证了辐射单元具有良好的幅相特性。馈电网络和辐射单元均印刷在介电常数为2.65的介质基板上,使得天线结构简单、成本低、易加工。将印刷有辐射单元和馈电网络的介质板放置于直角反射器内提高天线的增益。测试结果显示,该天线电压驻波比(VSWR)≤2的相对阻抗带宽达到21.4%(7.00~8.68 GHz),在对应的阻抗带宽内,天线增益达到17 dBi。 相似文献
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在传统Vivaldi天线结构的基础上,设计了两种适用于宽带信号收发系统的改进型渐变槽Vivaldi天线以及同轴馈电型对踵Vivaldi天线,并利用电磁仿真软件HFSS对这两种Vivaldi天线的性能进行优化分析.通过对不同结构Vivaldi天线的对比分析结果可以看出改进型渐变槽Vivaldi天线和同轴馈电型对踵Vivaldi天线在频段、带宽、驻波比等方面均达到宽带传输系统的设计要求. 相似文献
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多频段印刷振子天线的分析与试验 总被引:1,自引:0,他引:1
本文讨论了由同轴线馈电、背面带有接地板的宽印刷振子天线的特性。文中着重分析了天线的几何参数对天线带宽特性的影响,进行了一定的试验,得到了一些实际有用的结论。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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. 相似文献
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Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers
A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献
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A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working. 相似文献
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《中国通信》2014,(7)
正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks 相似文献