1.03THz折叠波导慢波结构及电子光学系统研究

太赫兹真空电子器件成为未来主要的发展方向,本文对1.03 THz折叠波导慢波结构及电子光学系统进行了研究,分析了不同电子注通道形状对于折叠波导特性的影响,包括色散特性、耦合阻抗、衰减特性、功率、增益等,并且利用OPERA 3D软件设计了电子光学系统。仿真结果表明,在中心1.03 THz频率处,与矩形电子注通道折叠波导慢波结构相比,圆形电子注通道的结构色散曲线更为平缓,耦合阻抗提升6.9%,损耗降低6.8%;在10 GHz带宽内功率提升47.4%,增益提升1.2 dB,互作用长度缩短12.3%。在工作电压为17.4 kV时,阴极发射电流大于3 mA,电子注半径为0.012 mm,在均匀区永磁聚焦系统中可稳定传输。     

太赫兹折叠波导慢波结构的设计与微加工

从行波管工作的物理特性提出了一种获得折叠波导慢波结构参数的简单方法,给定工作频率和电压,能够获得折叠波导慢波结构的初始参数.设计了D波段的折叠波导结构来验证该方法,对其冷测特性如色散、耦合阻抗进行了分析.仿真结果表明,设计的折叠波导慢波结构在中心频率处具有较平缓的色散关系,在中心频率处耦合阻抗为3.5欧姆.在电子注电压为20.6 kV,电流为15 mA时,27 mm(50个周期)的折叠波导慢波结构在220 GHz具有13.5 dB的增益,3 dB带宽为11 GHz(213~224 GHz).同时讨论了折叠波导慢波结构的微加工工艺,并通过UV-LIGA工艺获得了实验样品.     

0.41 THz折叠波导慢波结构分析与设计

在0.14 THz,0.22 THz和0.34 THz折叠波导行波管研制的基础上,讨论了0.41 THz折叠波导行波管慢波结构设计与加工的可行性,分析研究了折叠波导慢波结构弯曲处直角弯曲与半圈弯曲、方形电子注通道与圆形电子注通道对色散特性、耦合阻抗、带宽、冷损耗和增益的影响。考虑了慢波结构中增加理想衰减器对该行波管带宽和增益的影响,得到了0.41 THz折叠波导行波管慢波结构的初步设计方案,为太赫兹折叠波导行波管的继续发展打下了一定基础。     

E波段折叠矩形槽波导行波管的研究

分析了一种适用于E波段81~86 GHz空间行波管的新型慢波结构——折叠矩形槽波导.折叠矩形槽波导来源于传统的矩形槽波导,将E面沿其纵向来回弯曲而形成.利用电磁场仿真软件Ansoft HFSS设计优化并最终确定了E波段折叠矩形槽波导的关键几何尺寸.同时,模拟仿真出了折叠矩形槽波导在中心频率f=83.5 GHz处的耦合阻抗沿x和y方向上的变化趋势,得出其可通过加载带状电子注获得更高的平均耦合阻抗.利用CST粒子工作室模拟得出:折叠矩形槽波导行波管在中心频点83.5 GHz处输出功率为210 W,电子效率达到8.05%.     

0.34 THz折叠波导行波管设计及流通管实验

以0.34 THz折叠波导行波管为研究对象,分析了慢波结构的色散特性、耦合阻抗、冷损耗特性和工作模式等,并按优化后折叠波导慢波结构的要求设计电子光学系统,进行流通管实验,得到电子注通过率大于80%的实验结果。最后对输入输出结构进行优化设计,满足中心频率为0.345 THz,带宽大于10 GHz,输出功率大于20 mW的0.34 THz折叠波导行波管设计要求。     

G波段双注折叠波导行波管的注-波互作用特性

研究了G波段双注折叠波导(FWG)TE20模的基本特性。首先计算了双注FWG TE20模的高频特性,采用等效电路法计算了色散特性;根据定义式计算了耦合阻抗,同时将二者的计算结果与HFSS仿真结果进行对比。结果显示,色散特性随频率升高差距增大,耦合阻抗随频率升高差距降低。利用电磁仿真技术(CST)粒子模拟软件对双注FWG TE20模的注-波互作用情况进行仿真,得到了慢波结构中电子轨迹以及输入输出信号频谱图,结果表明,在工作频率为205 GHz时,四段FWG的增益为34.74 dB。     

W波段多种槽加载折叠波导行波管的研究

该文提出了3种槽加载折叠波导行波管慢波结构:三角形、梯形和燕尾形槽加载折叠波导。分析比较了不同槽形状对慢波结构的色散特性和耦合阻抗的影响。利用粒子模拟的方法对W波段4种槽加载折叠波导行波管的非线性注-波互作用进行了研究;在相同的电子注参数和输入功率的条件下,对输出功率、电子效率和增益等参量进行了比较。在多种槽加载结构中,梯形槽加载折叠波导输出功率(255 W)和增益(37.1 dB)最大,电子效率最高(10.7%);燕尾形槽加载折叠波导达到饱和所需要的互作用电路最短(64.2 mm);三角形槽加载折叠波导的3 dB带宽最宽。     

0.22 THz宽带折叠波导慢波结构的设计

通过对折叠波导的理论分析,提出一种快速设计折叠波导慢波结构的方法。优化设计了中心频率为0.22 THz的折叠波导慢波结构,分析了结构参数对高频特性的影响。为防止振荡,仿真中采用截断的慢波结构。互作用仿真表明,在电子注电压为16 kV,电流为10 mA情况下,中心频率处增益为23.9 dB,输出功率为1.2 W。其中3 dB带宽大于14 GHz(0.214 THz~0.228 THz),带内输出功率大于0.5 W,在7 GHz(0.217 THz~0.224 THz)范围内输出功率大于1 W。     

0.14 THz折叠波导行波管的设计与实验

对折叠波导慢波结构进行了研究,对其色散特性和耦合阻抗进行分析,并设计了输能窗和电子光学系统,在此基础上进行了粒子模拟的束波互作用计算。通过设计,对0.14 THz 行波管进行了制管工艺的研究,包括慢波结构的加工和焊接等,完成了热测实验。在电压为16.3 kV,电子流通率为74%条件下,测试得到最大饱和输出功率3.1 W,输出频率140.08 GHz,增益27 dB,最大功率半带宽2.82 GHz。     

太赫兹扩展互作用振荡器的矩形耦合腔特性研究

本文选用矩形耦合腔作为太赫兹扩展互作用振荡器(EIO)的慢波结构,鉴于其结构的复杂性,采用等效电路方法计算其色散.详细研究了腔体和耦合槽的电路参数,计算了不同结构尺寸、圆形和矩形电子通道的0.12THz和0.225THz慢波结构的色散特性.并采用专业电磁软件,研究了不同结构参数下的色散特性、耦合阻抗和特征阻抗.通过对色...     

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.     

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.     

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.     

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.     

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.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

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.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

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.     

Call for Papers

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