感应耦合等离子体的功率耦合效率的理论分析与计算

基于变压器模型,本文对感应耦合等离子体中线圈产生的空间电场分布、等离子体电阻、电感及功率耦合效率等进行了数值计算.在计算过程中,考虑了低气压等离子体无碰撞随机加热机制的作用.结果表明,同心线圈的感应电场呈中空分布,径向和轴向均呈现很大的不均匀性;功率耦合效率随线圈品质因数Q及耦合系数K的增大而增大.功率耦合效率的理论分析和计算为线圈优化设计提供了依据.     

大型低地球轨道空间等离子体环境模拟实验系统设计

在介绍国外的相类似设备系统基础上,概述了我国大型低地球轨道空间等离子体环境模拟实验系统建设背景与应用;简述了我国该模拟实验系统组成和主要配置;论述了系统的等离子体环境、空间尺度等设计依据、方法及其具体参数;并详细阐述了真空系统、离子源系统、磁场产生装置、电场产生装置、太阳模拟器等主要分系统与装置的设计原则、方案以及性能指标。该系统可为卫星平台空间环境探测有效载荷及传感器的试验、验证、性能测试与评估提供有力的设备和技术支撑,也可为低密度冷等离子体与磁场、电场及定向粒子流相互耦合效应等观测、实验与理论研究提供环境和技术条件。     

张衡一号空间电场探测仪设计北大核心CSCD

张衡一号空间电场探测仪为我国首发电磁监测试验卫星(CSES)主载荷。基于探测原理以及与轨道等离子体环境电势耦合模型,论述了张衡一号双探针式空间电场探测仪设计基本原则和依据;针对不同的轨道等离子体环境条件和鞘层厚度,阐述了相应的球形探针收集电流、相对耦合电势及鞘层阻抗的数学表达,分析了该探测仪电场探测精度的影响因素以及主动偏置电流效应,研究表明,对于CSES飞行轨道环境条件,采用施加负向偏置电流,可使得探针鞘层阻抗小于1×105Ω,从而提高空间电场探测精度;研究了张衡一号空间电场探测仪探针间耦合电势差测量等效电路模型和球形探针最小几何半径设计约束条件,结果表明,对于CSES飞行轨道通常等离子体环境条件,当球形探针几何半径r3×10-2m时,可实现两球形探针电势差测量偏差系数α!10-6的设计要求。在以上基础上,叙述了张衡一号空间电场探测仪球形探针结构与电子学设计,并简述了探测系统主要组成、工作模式和频段等。     

张衡一号空间电场探测仪设计

张衡一号空间电场探测仪为我国首发电磁监测试验卫星(CSES)主载荷。基于探测原理以及与轨道等离子体环境电势耦合模型,论述了张衡一号双探针式空间电场探测仪设计基本原则和依据;针对不同的轨道等离子体环境条件和鞘层厚度,阐述了相应的球形探针收集电流、相对耦合电势及鞘层阻抗的数学表达,分析了该探测仪电场探测精度的影响因素以及主动偏置电流效应,研究表明,对于CSES飞行轨道环境条件,采用施加负向偏置电流,可使得探针鞘层阻抗小于1×105Ω,从而提高空间电场探测精度;研究了张衡一号空间电场探测仪探针间耦合电势差测量等效电路模型和球形探针最小几何半径设计约束条件,结果表明,对于CSES飞行轨道通常等离子体环境条件,当球形探针几何半径r3×10-2m时,可实现两球形探针电势差测量偏差系数α!10-6的设计要求。在以上基础上,叙述了张衡一号空间电场探测仪球形探针结构与电子学设计,并简述了探测系统主要组成、工作模式和频段等。     

微波等离子化学气相沉积金刚石膜新型微波谐振腔设计

提出新型微波谐振腔用于化学气相沉积金刚石薄膜,腔体有效体积可以调节,采用环形介质窗口,置于沉积基台的下方,允许产生较大并且温度较高的等离子体。同轴内导体与沉积台相连接,微波从谐振腔底端传输经同轴导体耦合进入腔体。采用有限元的方法优化谐振腔的尺寸,使其能耦合进更大的微波能量,优化后,最大电场区域位于沉积台上方,并且均匀分布,在腔体内其它区域和介质窗口附近电场强度则很小,满足设计要求。采用时域有限差分法模拟了谐振腔在一定微波输入功率下产生等离子体的特性,并对设计的谐振腔进行试验研究,实验观察到的等离子体位置与模拟结果一致。     

应用于超大规模集成电路工艺的高密度等离子体源研究进展

本文简要地介绍了等离子体的产生方式以及传统的射频电容耦合等离子体源。对电子回旋共振等离子体(ECR) ,感应耦合等离子体 (ICP) ,螺旋波等离子体 (HWP)等几种新型的高密度等离子体源[1] 的工作原理及结构重点作了分析讨论 ,并从运行参数上对其进行了比较。最后对高密度等离子体工艺加工中的等离子体约束以及器件损伤问题的最新研究进展进行了介绍     

等离子体加工光学元件装置技术研究

介绍了一种新型的超光滑表面加工技术-等离子体抛光.设计和安装了一套等离子体加工试验平台.加工试验平台由真空系统、等离子体源、射频电源系统、气路系统组成.试验平台具有独立变量气体流量、真空度、射频电源发射功率和反射功率和加工时间.对于石英玻璃材料的实验结果表明等离子体抛光是一种可行的有潜力的抛光技术.     

应用于超大规模集成电路工艺的高密度等离子体源研究进展

本简要地介绍了等离子体的产生方式以及传统的射频电容耦合等离子体源。对电子回旋共振等离子体（ECR），感应耦合等离子体（ICP），螺旋波等离子体（HWP）等几种新型的高密度等离子体源^[1]的工作原理及结构重点作了分析讨论，并从运行参数上对其进行了比较。最后对高密度等离子体工艺加工中的等离子体约束以及器件损伤问题的最新研究进展进行了介绍。     

金刚石膜气相沉淀技术中微波等离子体反应腔的数值模拟

采用有限积分法(FIT算法) ,并利用一种简单的等离子体模型模拟了具有轴对称的微波等离子体反应腔中微波场与等离子体的行为。计算出了给定等离子体的空间分布时电场的分布情况 ,以及给定电场的空间分布时等离子体的分布情况 ,从而得到微波———等离子体反应腔中电磁场稳定分布以及等离子体的放电位置。并依据实验中的一些可变参数 ,寻求影响等离子体放电位置的参数 ,为设计化学气相沉淀(CVD)技术沉积大面积金刚石膜微波反应腔提供依据     

空间电场探测球形传感器表面涂层光电特性研究

空间电场探测球形传感器是利用卫星平台在空间耦合等离子体电势的敏感部件。球形传感器通常采用加工性能良好、质轻的铝合金材料,表面涂覆导电涂层。而涂层的光电特性会影响电场的测量精度。本文对涂层光电特性对光电子流的影响、对接触电势的影响两个方面进行了理论分析;并就传感器材料铝合金2A12基底、涂层环氧掺碳材料DAG213为研究对象,测量并研究了可表征其光电特性的功函数及其变化;研究结果表明,DAG213涂层表面功函数较铝合金基底有不少于1eV的提升,且标准差有不少于0 eV的降低,说明DAG213涂层的功函数更为均匀,更有利于提高传感器在空间的电场测量精度。     

Measurements and Computations of Electric Field Intensity and Power Density

Conversion equations for converting the transmitting power, receiving power, or receiving voltage to electric field intensity and power density are derived and discussed. If the antenna factor, antenna gain, and the cable parameters are known, the electric field intensity or power density at some distance from the transmitting antenna may be determined by means of a specific conversion equation for a given signal frequency. The developed conversion equations may aid the electronics engineers to compute the electric field intensity and power density in a quick way.     

Voltage response and field reconstruction for a miniature fieldprobe in a spatially nonuniform electric field

A miniature E-field probe employing a 0.6-mm linear dipole antenna has been developed. The authors describe an analytical study of the probe's response to a spatially varying electric field. On the basis of the Nyquist sampling theorem, the spatial sampling frequency at which an electric field should be measured for good reconstruction is established. Using antenna theory, the voltage response of the probe is found in terms of the antenna's transmitting current and the measured electric field. This relationship is used to reconstruct the electric field from a set of discrete voltage responses. A method-of-moments program has been developed to determine numerically the voltage response of the antenna structure to a spatially varying electric field. Numerical results, which allow for the testing of certain theoretical findings important for analyzing measurement data, are presented. Although developed for only one-dimensional fields, the methodology can be applied to general three-dimensional fields     

Electro-optic lightning detector

The design, alignment, calibration, and field deployment of a solid-state lightning detector is described. The primary sensing component of the detector is a potassium dihydrogen phosphate electro-optic crystal that is attached in series to a flat-plate aluminum antenna; the antenna is exposed to the ambient thundercloud electric field. A semiconductor laser diode (lambda = 685 nm), polarizing optics, and the crystal are arranged in a Pockels cell configuration. Lightning-caused electric field changes are related to small changes in the transmission of laser light through the optical cell. Several hundred lightning electric field change excursions were recorded during five thunderstorms that occurred in the summer of 1998 at the NASA Marshall Space Flight Center in northern Alabama.     

Azimuthal polarization and partial coherence

Partially coherent fields with the electric field parallel to the azimuthal coordinate are analyzed by use of the exact angular spectrum representation. The known results for fully coherent fields are used to find the permitted forms of azimuthally polarized, partially coherent fields. The derived result is then used to show that this class of fields is severely restricted because the azimuthal polarization state is particularly sensitive to the correlation properties of the electric-field components. Two examples of azimuthally polarized fields are briefly examined. The first is a class of nondiffracting fields that retain the polarization state upon propagation, whereas the second is an example in which the azimuthal polarization is broken because the cross-spectral density function is not of the permitted form.     

Description of the propagation of a radially polarized beam with the scalar Kirchhoff diffraction

Since radially polarized beams have only one magnetic field component, the azimuthal component, a scalar Kirchhoff diffraction integral can be used to describe the propagation of the magnetic field. In the far-field zone, this diffraction formula gives an analytic expression for the magnetic field from which the electric field component expressions are derived by the Faraday relation. Numerical results from these expressions correctly reflect the properties of a radially polarized beam.     

Perturbation calculation of charged-particle motion and phase-free acceleration in electromagnetic fields

The cyclic motion of charged particles in azimuth-independent electromagnetic fields varying in time has been studied in first-order perturbation theory. It is shown that the addition of an azimuth-dependent azimuthal electric RF field changing sign at the stationary orbit radius combined with radial oscillations, allows a second-order phase-free acceleration. Possible applications are discussed.     

大面积平面表面波等离子体的研究

低温等离子体技术已被广泛应用于各高科技领域 ,并且应用范围仍然在迅速拓展 ,这对等离子体本身提出了更高的要求 ,平面大面积、高密度均匀等离子体源是目前最迫切的需求之一。作者主要介绍表面波激发等离子体的原理 ,并在自行研制的一套平面大面积表面波等离子体源上 ,利用静电双探针测量了其Ar气放电的角向、径向和轴向的电子密度和温度。发现角向电子密度和温度均匀性与耦合天线及气压密切相关而与入射功率无关 ;径向电子密度和温度均匀性则与入射微波功率及气压密切相关而与耦合天线无关。因此 ,通过优化耦合天线来获得径向参数的均匀性及微波耦合效率 ,并增大微波功率、选择适当的气压 ,可产生大面积平面高密度等离子体     

Combined antenna and localized plasmon resonance in Raman scattering from random arrays of silver-coated, vertically aligned multiwalled carbon nanotubes

The electric field enhancement associated with detailed structure within novel optical antenna nanostructures is modeled using the surface integral equation technique in the context of surface-enhanced Raman scattering (SERS). The antennae comprise random arrays of vertically aligned, multiwalled carbon nanotubes dressed with highly granular Ag. Different types of "hot-spot" underpinning the SERS are identified, but contrasting characteristics are revealed. Those at the outer edges of the Ag grains are antenna driven with field enhancement amplified in antenna antinodes while intergrain hotspots are largely independent of antenna activity. Hot-spots between the tops of antennae leaning towards each other also appear to benefit from antenna amplification.     

Electric field meter with a dipole antenna in an elliptically polarized electric field

A model of an electric field meter with a dipole antenna is analyzed. The model takes into account the fact that the meter incorporates other elements with a conducting surface in addition to the dipole antenna, viz.: a matching device, a signal cable, and a voltmeter. Alternative forms of the measurement equation are obtained, which differ in the error associated with the currents induced by the measured electric field on the braid of the signal cable and on the casing of the voltmeter. It is shown that this error can be eliminated partially or completely by performing additional measurements with the dipole antenna in different positions.Translated from Izmeritel'naya Tekhnika, No. 2, pp. 45–48, February, 1994.     

基于CST软件的电火工品射频安全性分析

为了研究电火工品在复杂电磁环境下的射频安全性，针对某型电火工品建立了偶极子天线模型。基于CST电磁仿真软件，仿真得到了该天线模型的增益参数，进一步仿真计算得到了在频率为0．75GHz、电场强度为195V／m的电磁环境下，进入到该电火工品的射频功率，并与实际计算结果进行了对比验证。通过多频点仿真计算，得到了该天线模型的增益随频率变化的规律，即在0．5—2．0GHz的频率范围内，天线模型的增益随着频率的增大而增大。