EAST 装置电子回旋共振加热系统波纹圆波导研究*

在EAST装置上正在建设140GHz/4MW/1000s电子回旋共振加热(ECRH)系统,单个回旋管输出的1MW功率通过波纹圆波导传输到天线聚焦镜上,然后经天线反射镜进入等离子体。运用表面阻抗法对波纹圆波导进行了理论分析,针对EAST装置ECRH系统需求的140GHz波纹圆波导进行了设计研究,所设计的波导传输模式为HE11模,具备1MW连续波运行能力且欧姆损耗低于0.02d B/100m,同时分析了HE11模在波导口外辐射模式及其与TEM00模耦合特性。     

Pump Uniformity and Temperature Profile Measurements in a Planar Waveguide Nd:YAG Laser by a Beam Deflection Method

A planar waveguide laser using a large-core Nd:YAG waveguide and face-pumping by diode bars has produced a multimode power up to 160 W, with direct-contact water-cooling across the largest faces of the waveguide in the lateral direction. A method is reported that measures the nonuniform heat dissipation in the waveguide core and nonuniform water-cooling through deflection of a helium-neon laser beam passing through the waveguide claddings. Temperature gradients resulting from the varying heat transfer coefficient to the coolant are quantified, together with lateral thermal lens effects associated with edge-cooling and nonuniform pumping. The heat flux in the claddings is compared for two different waveguide structures, giving information on multipass face-pumping efficiency and uniformity.     

Millimeter-Wave Antenna of a Travelling-Wave Long Sinusoidal Slot in the Narrow Face of a Rectangular Waveguide

A travelling-wave long sinusoidal slot in the narrow face of a millimeter-wave (Ka-Band) rectangular waveguide is investigated. To the best of our knowledge, a slot of this shape is applied to the narrow face of a rectangular waveguide for the first time at this frequency range. The analytical study is based on the magnetic current model. Experimentally, far-field and S-parameters are measured and a good match is obtained between analytical and measured patterns. Frequency scan rates and velocity ratios of the structure are calculated. The effect of the sinusoidal slot’s geometrical parameters (amplitude, period and number of periods) on the radiation patterns is also investigated. The drawback of the sinusoidal radiator is its cross-polarized beam that is not convenient for antenna applications. These co and cross-polarized beams scan in two different angle regions. To filter/suppress the cross-polarized beam, a grid polarizer is mounted to the sinusoidal slot and a 15 dB suppression level is reached. S-parameters measurement shows that the antenna efficiency increases remarkably after the application of the grid polarizer to the slot.     

On the Wave Propagation and Mode Conversion in a Helically Corrugated Multimode Circular Waveguide

For specific forms of excitations, the normal modes and mode coefficients of a lossless helically corrugated circular multimode waveguide are determined from the appropriate boundary conditions. Because of the multiplicity of the roots of the characteristic dispersion equation obtained, care must be exercised in the evaluation of the equation and in the interpretation of the /spl omega/-/spl beta/ diagram. For the TE/sub 11/ mode excitation, it is shown that increasing either the depth or the width of the corrugation enhances the conversion into the TM/sub 11/ mode, whereas increasing the pitch reduces the TM/sub 11/ mode conversion. Mode conversion always increases with increasing frequency. The theoretical results are in agreement with the results of measurement.     

风廓线雷达的波控系统设计

介绍了应用快捷的查表法完成风廓线雷达天线阵面单元的一次布相。其特点是可移植性强,体积小,重量轻,布相时间短,并具有BIT功能。这种方法对有限相控天线有较好的通用性。     

用转镜扫描系统测量脉冲激光的二维光强分布

设计了一种用转镜扫描法测量高重复频率脉冲激光器输出光强二维分布的系统，给出了高重复频率脉冲TEACO2激光器运场光强分布的测试结果。     

基于GSM的移动监控定位系统设计

移动监控定位系统在车辆调度、航海导向、公安巡防、银行运钞车监控等领域应用十分广泛。本文首先介绍了移动监控定位系统可选择的几种通信网，然后分析了基于GSM移动通信网的3种设计方法，最后给出了移动监控定位系统提供的业务功能。     

Calculations on Mode Eigenvalues in a Corrugated Waveguide with Varying Diameter and Corrugation Depth

Journal of Infrared, Millimeter, and Terahertz Waves - The present paper addresses numerical calculations on the eigenvalues of hybrid modes in corrugated circular waveguides with varying diameter...     

Design of a Millimeter-Wave Concentrator for Beam Reception in High-Power Wireless Power Transfer

This study examined the performance of a developed taper-tube concentrator for 94-GHz millimeter-wave beam reception during wireless power transfer. The received energy is converted into kinetic energy of a working gas in the tube to drive an engine or thruster. The concentrator, which is assumed to have mirror reflection of millimeter waves in it, is designed to be shorter than conventional tapered waveguides of millimeter waves. A dimensionless design law of a concentrator is proposed based on geometric optics theory. Because the applicability of geometric optics theory is unclear, the ratio of its bore diameter to its wavelength was set as small compared to those in other possible applications. Then, the discrepancy between the designed and measured power reception was examined. Results show that the maximum discrepancy was as low as 7 % for the bore-to-wavelength ratio of 20 at the narrow end of the concentrator.     

2D FDTD Algorithm for the Analysis of Lossy and Dispersive Millimeter-Wave Coplanar Waveguide

The dispersion and loss characteristics of millimeter-wave coplanar waveguides (CPWs) are analyzed by using an efficient two-dimensional finite-difference time-domain (2D FDTD) algorithm. Combined with graded mesh technique, alternating direction implicit technique and curve-fitting technique, this proposed algorithm verifies its accuracy and efficiency through an example of infinite-ground CPW. Moreover, the influence of ground-plane width on CPW's loss characteristics is analyzed. Bulk micromachined CPWs with low loss are also analyzed by the proposed algorithm.     

Instabilities Driven by an Intense Beam in a Plasma-Filled Dielectric-Lined Waveguide Immersed in a Finite Axial Magnetic Field

A linear analysis is described on stabilities driven by an intense relativistic electron beam in an infinitely long, plasma-filled, and dielectric-lined circular waveguide immersed in a finite strength axial magnetic field. A dispersion equation is derived from the cold fluid theory and solved numerically. Beam-plasma instabilities due to interaction between beam modes and the Trivelpiece-Gould modes appear as well as the Cherenkov and the cyclotron Cherenkov instabilities. Parametric researches are carried out varying magnetic field strength, plasma density, and dielectric constant. Effects of a finite magnetic field and plasma filling are discussed in connection with the possibilities of using this system as a microwave radiation source.     

Recent Upgrades and Extensions of the ASDEX Upgrade ECRH System

The multi-frequency Electron Cyclotron Heating (ECRH) system at the ASDEX Upgrade tokamak employs depressed collector gyrotrons, step-tunable in the range 105?C140 GHz. The system is equipped with a fast steerable launcher allowing for remote steering of the ECRH RF beam during the plasma discharge. The gyrotrons and the mirrors are fully integrated in the discharge control system. The polarization can be controlled in a feed-forward mode. 3 Sniffer probes for millimeter wave stray radiation detection have been installed.     

Calculation of TM/sub 0n/ Dispersion Relations in a Corrugated Cylindrical Waveguide

The TM/sub 0n/-mode Maxwell equations in a cylindrical geometry are converted to a state-vector system of coupled linear differential equations, in which the boundary conditions for a waveguide of varying diameter are included in the coefficient matrix of the state-vector system. The particular problem of periodic boundary conditions is solved for a waveguide with a sinusoidally undulating wall.     

基于SMS短信报警的化工厂三废排放监控系统研制

针对现有的对环保局对各单位三废排放量采用抽检不便于管理的现状，提出了利用传感器实时采样三废排放数据并判定是否超标，如果超标则通过数据采集系统上的TC35MODEM以手机短信的方式通过无线通讯网将超标数据发送到环境监测部门以及单位相关管理人员以便处理的系统。该系统具有报警和查询功能。     

开放腔通过渐变波导过渡段和矩形波导的耦合

本文绘出具有新型润合机构——渐变被导过渡段的开放腔耦合品质因数的计算方法。开放腔耦合品质因数的计算是基于不完全伽略金方法和边界点上半逆法的使用。计算值和实验值相比较，两者吻合得较好。     

直流电源系统监控装置的研制

介绍一种基于多个单片机的直流电源监控系统。系统采用主从式结构，主机负责整个系统的控制和管理，从机则分别负责监督控制系统的直流、交流、充电模块及蓄电池组等各个部分。该系统具有可靠性高、成本低廉、灵活性好等特点。     

轨交通信网用裂缝波导结构设计的探究

本文简述了用于轨交列车自动控制系统中作为通信传输线的裂缝波导的结构设计。根据工程实际,对需要注意的热胀冷缩问题和防水问题进行了分析和设计,提出并实现了解决方法。     

基于现场总线的电梯监控系统开发

为了提高“PLC”、“计算机控制”及“现场总线”等课程的教学效果,本文设计了一套基于现场总线的电梯监控系统。该系统将工业现场最为常用的PLC、现场总线、变频器、触摸屏及工控组态软件等构成一个完整的控制系统,使学生对现场总线控制系统和可编程序控制器系统的工作过程有一个直观的了解。     

广播电视监播系统简介

广播电视监播系统是利用先进的语音识别技术,针对广播电台、电视台的节目内容进行监控的设备,是一套完备的自动化、智能化、网络化的监播系统。介绍并对比了国内外广播电视监播系统的功能、结构和发展,具有良好的市场前景。