真空射频阻抗自动匹配方法分析

本文介绍了真空射频电源使用时阻抗匹配的作用,阻抗自动匹配系统的实现方法,剖析了射频阻抗匹配器结构。在此基础上针对射频阻抗自动匹配目前所采用的算法和技术进行了研究,从控制系统的角度提出了从快速性、稳定性和智能性三方面来提高阻抗匹配的效率和匹配效果。最后对真空射频阻抗自动匹配系统广阔的应用前景进行了总结和展望。     

宽束射频离子源匹配网络

介绍宽束射频离子源原理及结构，分析射频匹配网络中调谐和负载电容与输入频率、离子源电阻、传输线特征阻抗、支路电感的关系，导出了射频离子源阻抗公式。     

非接触型IC卡对读写机具影响的数学模型与射频匹配网络的设计

针对非接触型IC卡对读写机具参数的影响,建立了相应的数学模型.通过数学模型进行仿真,代入设定的参数值求解,定量求出非接触型IC卡对读写机具参数的影响程度.为了实现IC卡和读写机具之间最佳能量传输,需要在源和负载之间加一匹配网络以达到阻抗匹配,最后推导并验证了读写机具射频匹配网络的计算公式.     

VC环境下Smith阻抗图的实现

主要介绍用于进行电路阻抗分析、匹配网络设计的Smith阻抗图。Smith阻抗图是分析待测器件反射系数、驻波比和阻抗的重要工具，并且常用于矢量网络分析仪中。重点叙述了Smith阻抗图的基本原理、VC的图像处理和在VC环境下绘制Smith阻抗图的方法，并说明了如何在Smith阻抗图中找到某个特定高频电路的负载阻抗。     

超声换能器的“电感-变压器”阻抗匹配模型研究

在分析超声换能器阻抗特性和电路匹配的基础上,对传统纯电感电容匹配电路模型进行电路仿真和阻抗分析,证明该模型在谐振频率附近有大范围的电抗变化,存在电路不稳定和电阻调节精度低的问题;提出"电感-变压器"阻抗匹配模型,通过电感和变压器分别调节换能器电阻和电抗,实现电路的精确匹配,以提高超声换能器阻抗匹配的精度和稳定性,并给出了理想的匹配条件和匹配参数。利用匝数可调的变压器和电感制作了超声换能器的匹配电路,对20.8 k Hz的变幅杆换能器进行了阻抗匹配的实验测量,结果证明这种"电感-变压器"阻抗匹配模型在谐振频率附近具有较小的电抗变化范围、较低的电阻变化率和较高的电抗调节精度,在超声换能器的自动阻抗匹配中具有良好的应用前景。     

基于波导等效阻抗建模用于钛铁矿微波还原的谐振腔体研究

提出了一种利用等效阻抗的思想来设计微波谐振腔。通过计算传输波导的主模等效阻抗与谐振腔近似等效阻抗匹配来确定谐振腔体的尺寸,从而使多模谐振腔与传输波导具有良好的匹配,微波源能够以最小的反射馈入谐振腔内。以钛铁矿作为加热研究的物料,利用HFSS软件分别对单馈口和多馈口多模腔的反射系数进行了优化仿真,并且给出了腔体内场分布的情况,仿真优化的结果与等效阻抗匹配方法计算值接近,验证了根据波导等效阻抗方法来设计腔体结构的可行性,为设计高温微波冶金多模腔体提供了新的参考依据。     

阻抗匹配电路在电子测量仪器前端模拟通道中的应用

阻抗匹配电路是电子测量仪器前端模拟通道中的关键电路.在介绍电子测量仪器前端模拟通道组成、功能的基础七,阐述了阻抗匹配的作用,即实现信号最大功率传输和实现信号无反射传输.分析了选频匹配网络中常用的倒L型网络、T型网络和Ⅱ型网络的电路模型和电路参数设计计算方法,给出了实现阻抗变换的各种电压跟随器的电路结构形式,并对电子测量仪器前端T型阻抗匹配电路参数的计算进行了举例说明.     

TO30型三厘米标准负载

辽宁精密仪器厂生产的TO 30型三厘米标准负载是目前国内同频段负载中精确度最高的,中国计量科学研究院已开展这项检定工作,因此,它可作为驻波比或反射系数模的量值传递器具,适于计量部门、工厂和研究单位用来检定和校准微波阻抗测试系统,使用方法简便,准确可靠。 TO 30型标准负载包括三个无反射(全匹配)标准负载、四个失配标准负载(驻波比分     

模糊匹配在功率超声系统的应用

功率超声医疗设备在手术过程中由于负载是时变的,为了获取较好的超声乳化效果,要求系统具有进行动态阻抗匹配的能力,而进行动态阻抗匹配的关键在于负载的在线检测.本文首先利用模糊专家系统的有关概念,对动态负载的属性进行了分析,建立了反应动态负载特性的模糊向量.然后利用模糊匹配方法判断出当前负载的强弱,最后根据识别的负载进行动态阻抗匹配方案的选择.为超声振动系统的动态匹配问题提供了一种解决方法.     

声阻抗梯度渐进的高分子微粒吸声材料

吸声材料的表面阻抗是影响材料吸声性能的主要因素之一,受到材料的特征阻抗和厚度的影响。对于特定厚度的吸声材料,要获得优异的吸声性能必须是材料的表面阻抗大小适宜。文中从阻抗匹配的角度出发,分别选用具有不同特征阻抗的高分子微粒材料作为声波匹配层和声能耗散层,构筑一种特性阻抗呈梯度变化的高分子微粒梯度吸声材料。通过改变匹配层和耗散层的厚度来调节高分子微粒吸声材料的吸声性能。     

射频磁控溅射制备SiO_2膜

利用石英靶射频磁控溅射制备SiO2膜的工艺，采用L型阻抗匹配网络，并计算得到了等离子体的等效电容及等效电导。指出射频功率密度是最重要的沉积参数，靶面自偏压及SiO2膜沉积速率均随功率密度的增加而线性增加。溅射气压及氧分压对自偏压的影响较小，但两者的增加将导致SiO2沉积速率的降低。制备了可见光区透光性良好，折射率为1．46，沉积速率为35nm／min的SiO2膜。     

Magnetron sputtering modes during pulsed deposition process determined by the analysis of power supply parameter

The goal of this paper is to present a new control method of reactive magnetron sputtering. The processes of reactive magnetron sputtering of aluminum target in Ar + O₂ atmosphere in high efficiency deposition and low efficiency deposition mode were studied. The mode of magnetron operation — metallic, transient, reactive (compound) — was determined by the analysis of medium frequency (MF) magnetron voltage and current waveforms and a circulating power (power supply parameter). This parameter enables monitoring of any mismatch between plasma-magnetron impedance and the resonant circuit of power supply. The experiments show that the Al_xO_y layer formation conditions could be determined by use of the power supply parameters. Conclusions were supported by the refractive index and dielectric constant measurements.     

钢基耐磨SiC薄膜制备研究

用磁控溅射的方法在40Cr钢的表面制得了SiC薄膜.通过X射线衍射、傅里叶红外光谱分析、摩擦磨损以及划痕试验研究了工艺参数、溅射方式对薄膜性能的影响.结果表明:室温下,用磁控溅射法制备的SiC薄膜具有非晶态结构;傅立叶红外光谱证实了薄膜中除了Si-C键的存在外还有大量的Si-Si键;在相同的工艺参数下用射频溅射法制备的薄膜表面更为光滑致密,与基体结合更好;采用射频溅射法,在功率200W,时间为2h,工作气压为0.1Pa条件下制备的SiC薄膜性能最佳.     

RF磁控溅射制备Al_2O_3薄膜及其介电性能研究

以-αAl2O3为靶材,采用射频磁控溅射法制备了非晶Al2O3薄膜。利用X射线衍射仪、扫描电镜、划痕仪、表面粗糙轮廓仪和阻抗仪研究了不同溅射功率和不同溅射气压对薄膜制备的影响,探索了不同溅射功率下制备的Al2O3薄膜的介电常数和介电损耗与频率的关系。试验结果表明,制备的非晶Al2O3薄膜表面平滑致密;随着工作气压的增加,薄膜沉积速率增加;随着溅射功率的增加,Al2O3薄膜的沉积速率和介电常数逐渐增加、介电损耗逐渐减小;随着频率的增加,Al2O3薄膜的介电常数逐渐减小,高频阶段趋于稳定。     

Orthogonal analysis for perovskite structure microwave dielectric ceramic thin films fabricated by the RF magnetron-sputtering method

The perovskite structure microwave dielectric ceramic thin films have been deposited by radio frequency (RF) magnetron sputtering on SiO₂(110) substrates. Subsequently, orthogonal analysis has been adopted to optimize the process parameters. The experimental results indicate that sputtering pressure has the greatest impact on comprehensive evaluation indicators such as the film quality, whereas sputtering power has a lower effect; the ratio of O₂/Ar and substrate temperature have the least impact on the process. Thus, the optimal process parameters to prepare perovskite structure dielectric thin films by RF magnetron sputtering are as follows: 200 W of sputtering power, 0.25 Pa of sputtering pressure, Ar as working gas, and substrate temperature of 610 °C.     

白宝石上生长SiO2薄膜的工艺

用射频磁控反应溅射法,以高纯Si为靶材,高纯O2为反应气体,在白宝石上制备SiO2薄膜。对影响薄膜生长的工艺参数进行了分析,测试了薄膜的成分,并研究了薄膜的红外光学性能。结果表明,制备的薄膜中Si和O形成SiO2化学键,计算出的O与Si的原子比接近2:1,采用射频磁控反应溅射法在白宝石上能够沉积出SiO2薄膜。制备出的SiO2薄膜对白宝石衬底有较好的增透作用。     

溅射功率和退火温度对GeSbTe相变薄膜内应力的影响

通过磁控溅射方法制备了GeSbTe薄膜.借助原子力显微镜,X射线衍射仪和应力测试仪等仪器,并结合对薄膜表面形貌和晶体结构的分析,研究了溅射功率和退火温度对薄膜内应力的影响.结果表明:当溅射功率较小时,内应力随着溅射功率的增大而增大,在50W左右时达到最大值,随后又随着溅射功率的增大而减小.退火温度为160℃时,薄膜发生非晶态向fcc晶态结构的相变,由于Te原子析出到晶粒边界,导致薄膜的内应力急剧增大到最大值为100MPa左右,而后随着退火温度的升高而下降,fcc结构向hex结构转变时,内应力变化并不明显.     

Effects of Homo-buffer Layer on Properties of Sputter-deposited ZnO Films

Two-step growth regimes were applied to realize a homoepitaxial growth of ZnO films on freestanding diamond substrates by radio-frequency(RF)reactive magnetron sputtering method.ZnO buer layers were deposited on freestanding diamond substrates at a low sputtering power of 50 W,and then ZnO main layers were prepared on this buffer layer at a high sputtering power of 150 W.For comparison,a sample was also deposited directly on freestanding diamond substrate at a power of 150 W.The effects of ZnO buffer layers...     

Influence of RF power on the electrical and mechanical properties of nano-structured carbon nitride thin films deposited by RF magnetron sputtering

Nano structured carbon nitride thin films were deposited at different RF powers in the range of 50 W to 225 W and constant gas ratio of (argon: nitrogen) Ar:N₂ by RF magnetron sputtering. The atomic percentage of Nitrogen: Carbon (N/C) content and impedance of the films increased from 14.36% to 22.31% and 9 × 10⁻¹ Ω to 7 × 10⁵ Ω respectively with increase in RF power. The hardness of the deposited films increased from 3.12 GPa to 13.12 GPa. The increase in sp³ hybridized C-N sites and decrease of grain size with increase in RF power is responsible for such variation of observed mechanical and electrical properties.     

Annealing dependence of residual stress and optical properties of TiO2 thin film deposited by different deposition methods

Titanium oxide (TiO(2)) thin films were prepared by different deposition methods. The methods were E-gun evaporation with ion-assisted deposition (IAD), radio-frequency (RF) ion-beam sputtering, and direct current (DC) magnetron sputtering. Residual stress was released after annealing the films deposited by RF ion-beam or DC magnetron sputtering but not evaporation, and the extinction coefficient varied significantly. The surface roughness of the evaporated films exceeded that of both sputtered films. At the annealing temperature of 300 degrees C, anatase crystallization occurred in evaporated film but not in the RF ion-beam or DC magnetron-sputtered films. TiO(2) films deposited by sputtering were generally more stable during annealing than those deposited by evaporation.