An Improved On-Wafer Measurement Method for PHEMT Modeling for Millimeter Wave Application

An improved on-wafer measurement method by using coaxial calibration instead of on-wafer calibration for PHEMT modeling is proposed in this paper. The advantage is that S-parameters of PHEMT device can be measured on wafer without impedance standard substrate (ISS) after the S-parameters of the microprobes have been determined. Excellent agreement is obtained between on-wafer calibration measurement and coaxial calibration measurements, respectively.     

化学反应溶液介电特性同轴式在线测量装置

 为解决化学反应溶液腐蚀测量探头的问题,提出了一种能实现宽带在线测量且测量探头不直接接触化学反应溶液的测量装置,并用这种测量装置采用全波仿真软件得到了用于重构溶液等效介电系数的散射参量。同时在假定2%测量误差的情况下,采用遗传算法反演溶液的等效介电系数。化学反应溶液等效介电系数的重构结果与文献值吻合较好,其相对误差小于5%,表明该测量装置在化学反应溶液介电系数的宽带在线测量中具有明显优势。     

不同封装方式对肖特基二极管高频性能的影响

肖特基二极管是太赫兹接收机的关键器件,通过在高频下对不同封装形式的肖特基二极管进行建模仿真,研究不同封装方式对肖特基二极管性能的影响。首先通过建立肖特基二极管的仿真模型,在高频结构仿真软件HFSS中对肖特基二极管在0~120GHz频段进行仿真,得到该肖特基二极管的S参数,并对S参数仿真结果和实测结果进行对比,证明了该二极管模型的准确性。然后分别建立肖特基二极管的普通封装模型和肖特基二极管的倒装芯片(flip-chip)封装模型,并对这两种封装模型进行仿真,得到其在两种不同封装结构下的S参数,进而对两种不同封装方式的S参数的-3dB带宽以及相位一致性进行对比分析。最终,对应用于太赫兹波段的肖特基二极管由于封装不同而带来的带宽以及相位的区别及其成因进行分析,论证了flipchip封装更适合应用于太赫兹波段的肖特基二极管,与普通封装相比,该封装在高频下对肖特基二极管的电性能有比较大的改进。     

New Measuring Apparatus for Complex Permittivity at Millimeter-Wave Frequencies

A dielectric rod resonator excited by a nonradiative dielectric waveguide is used for measuring complex permittivity of low loss dielectric materials. The complex permittivties of single crystal sapphire, polycrystalline Ba (Mg_1/2 W_1/2) O₃ and Mg₂ Al₄ Si₅ O₁₈ (cordierite) have been obtained at 60 and 77 GHz by the new apparatus. The first time the measurement results of complex permittivity of brain grey and white matters from 15 to 50GHz utilizing a two-port microstrip test fixture is presented. S-parameters of Test fixture are simulated employing the finite-element method. A new spectrometer for the precision measurement of dielectric permittivity and loss tangent, which is capable of providing high resolution data for the first time over an extended W-band (68-118 GHz) frequency for specimens with a large range of absorption values, including highly absorbing specimens that otherwise would not be possible.     

组件非线性响应人工神经网络建模及在传导干扰分析中的应用

根据描述大信号激励下组件响应的黑箱模型——非线性散射参数,提出利用有限实验数据通过人工神经网络建模获得组件非线性散射参数的方法,利用该方法对二极管构成的非线性组件的预测结果与实验测量结果吻合良好。推导了二端口非线性器件与三端口线性器件的非线性散射参数级联计算公式,并讨论非线性散射参数在传导干扰分析中的应用。通过具体实例的计算结果与实测结果的对比,证明了基于人工神经网络学习模型的非线性散射参数获取方法非常便于包含非线性组件的传导干扰分析,这对于系统级电磁效应分析具有重要意义。     

GaInP/GaAs异质结双极晶体管小信号模型参数提取的新方法

提出了一种直接提取GaInP/GaAs异质结双极晶体管(HBT)小信号模型参数的新方法.该方法基 于HBT器件S参数的测试数据，对HBT的小信号模型进行电路网络分析，利用S，Z，Y参数关系 以及电路“抽出”的技巧，分别对HBT小信号模型的寄生参数和本征元件参数进行提取，建 立了一套完整的直接提取HBT小信号模型参数的新方法.与文献报道HBT小信号模型参数提取 的方法相比，该方法的优点是，提取过程具有简明清晰的物理意义，无需建立特殊的测试结 构，无需引入繁琐的数学优化过程，提取速度快，并且具有比较好的精度和较宽频带范围的 适用性等. 关键词： GaInP/GaAs HBT 参数提取 小信号模型     

Small-signal modeling of GaN HEMT switch with a new intrinsic elements extraction method

A novel and accurate method is proposed to extract the intrinsic elements of the GaN high-electron-mobility transistor(HEMT) switch.The new extraction method is verified by comparing the simulated S-parameters with the measured data over the 5-40 GHz frequency range.The percentage errors E_(ij) within 3.83% show the great agreement between the simulated S-parameters and the measured data.     

基于NOA73微球与SU-8微柱的微探针制作

集成紫外固化胶NOA73微球与SU-8微柱制造的亚毫米探针,可以作为关键部件应用于三坐标测量机。NOA73微球通过NOA73对其他溶液的界面张力形成,柱子由深紫外光穿过微球曝光SU-8形成。这种新技术利用甘油补偿NOA73与空气折射率差,使得紫外光透过NOA73微球后保持接近平行。最终得到高深宽比的探针结构,高度超过1 200 m,微柱侧壁与基底呈89。     

Quantification of Fe2+/Fe3+ by Electron Microprobe Analysis – New Developments

Hyperfine Interactions - The measurement of the soft FeLα and FeLβ X-ray emission spectra by electron microprobe (flank method) allows the determination of the iron oxidation state in...     

包含源与负载耦合的滤波器诊断与调试方法

柯西法目前仅适用于诊断不包含源与负载耦合的带通滤波器。为解决这一问题,提出了一种能够诊断包含源与负载耦合的带通、带阻谐振腔滤波器的方法。利用遗传算法优化获得源与负载耦合系数并移除滤波器输入/输出端口处传输线引起的S参数的相位加载效应;使用柯西法一步确定仿真S参数对应的特征多项式;从获得的源与负载耦合系数和特征多项式中,利用已有的技术诊断出N+2阶耦合矩阵。此方法可用于指导滤波器的调试,通过对比理想的耦合矩阵与提取的耦合矩阵之间的差异,可确定滤波器问题出自何处以及调试的方向,从而加快滤波器的设计与实现。     

蒙特卡罗方法评定峰值检波器标定不确定度北大核心CSCD

针对高功率微波(HPM)脉冲测试用峰值检波器标定不确定度评估中测量函数非显式,直接测量量与被测量间概率分布传递困难等问题,研究建立了蒙特卡罗分析方法(MCM),利用有限带宽S参数网络时域响应计算原理建立了检波器标定系统的时域仿真模型,模型包含标定系统各微波器件S参数、检波电压、监测峰值功率等直接测量量,以及微波脉冲反射、叠加及传输延迟等物理过程。根据MCM原理对模型中各直接测量量引入特定分布的随机误差,通过重复计算,获得了检波器标定曲线的不确定度及其概率分布。     

Grating-enhanced through-wafer optical microprobe for microelectromechanical system high-resolution optical position feedback

We present modeling and experimental results from the use of a 1310-nm-wavelength through-wafer optical microprobe in conjunction with a microstructure grating to monitor the motion of a lateral comb resonator stage. The optical signal that results from shuttle interaction with the microprobe beam exhibits a peak-to-valley dynamic range that corresponds to 2-microm microstructure displacement, facilitating submicrometer positional resolution on digitization. This signal was used to achieve microstructure positional feedback and effective microsystem model parameter extraction, which are essential for structure control and model-based fault detection.     

Study of viscous liquids by spin micro- and macroprobe methods at 2-mm wave band EPR

The possibility of combined application of spin microprobe and macroprobe methods at 2-mm wave band EPR in determining the viscosity of a model system is demonstrated. Such an approach widens the range of dynamic viscosity EPR measurement in condensed systems and gives one the possibility to study separately various dynamic processes in a matrix.     

Solving the direct problem of quantitative electron microprobe analysis for binary alloys with a known composition

The results of solving the direct problem of quantitative electron microprobe analysis (calculation of the relative intensities of analyzed lines in a material with a known composition up to an accuracy of 2–5%) are presented. An additional matrix correction caused by the difference in the concentrations of atoms in the reference and sample is shown to be necessary for the microanalysis results and the value of this new fundamental correction is determined. The obtained solution of the direct problem is used to refine the value of an important parameter in electron microprobe analysis, i.e., the mass absorption factor of the analyzed X-ray line.     

多功能扫描质子核探针信号探测和数据获取系统

为了在一次扫描质子核探针实验中能获取多种物理信息,研制了多功能信号探测与数据获取系统。系统由组合探测器、多站多参量数据采集与束流扫描、样品台控制与显微观测三个子系统组成。组合探测器包括了Si(Li)X射线探测器,高纯Geγ射线探测器,以及Au(Si)面垒带电粒子探测器,可完成多种物理参数的同时获取。系统的核心数据采集与束流扫描系统基于NI公司的PXI-7852R数据采集卡和LabVIEW软件平台,具备了多个物理信号采集、多能谱显示以及束流扫描和二维成像等功能。六轴高精度真空样品台由计算机控制,可实现显微图像对样品的定位及对扫描区域的可视化选择。初步实验验证了该系统的可靠性与稳定性。     

Scattering by an E plane dielectric sheet in rectangular waveguide

A method for the computation of S-parameters associated with a rectangular waveguide with a rectangular dielectric obstacle is presented. The method uses the Method of Lines and discretization of the dielectric permittivity to treat the dielectric discontinuity along the discretization direction. In this way, the Method of Lines can be applied to analyze waveguide discontinuity with dielectric inhomogenousity along the discretization direction. The numerical results have been verified by both theoretical and experimental results.     

AlxGa1-xAs俄歇灵敏度因子的测定

利用PHI610俄歇谱仪测定了Al,Ga和As的俄歇灵敏度因子。对6种不同x值的Al_xGa_1-xAs样品进行俄歇定量分析。结果与X射线双晶衍射测量值非常一致。结果表明,利用自身谱仪测定的俄歇灵敏度因子进行的定量分析结果,与目前通常使用的手册或内标法提供的元素相对灵敏度因子的定量分析结果相比,测量精度得到大大提高。 关键词：     

Halfway-plane and continuum calculations of blocking dips for displaced atoms

Abstract

Redistribution of phosphorus dopant in 1N2175 phototransistors damaged by a pulsed neodynium laser has been investigated using the electron microprobe technique. Four different effects observed in the concentration profdes were explained by the action of diffusion and segregation, in the presence of temperature and compositional gradients. One specific effect was analyzed using a simplified model consisting of diffusion in the melt followed by the segregation upon refreezing. It was estimated that certain areas of the phototransistor surface remained above the melting point for times of the order of 10^?4 sec. Correlation was made between the results of these microprobe measurements and previously observed laser-damage effects in the electrical characteristics. It is suggested that impurity migration may be an important mechanism for damage to junction devices by pulsed lasers in an intermediate energy range.     

On the Recording of the Scattering Fields of Antennas in Their Near Zone

Radiophysics and Quantum Electronics - Using the complex S-parameters of the transmitting and receiving antennas, which constitute a communication channel, we propose and study the method for...     

Terahertz artificial dielectric cuboid lens on substrate for super-resolution images

This paper presents an investigation of terajets formation by dielectric periodic structure at terahertz frequencies (0.1–0.2 THz) in effective medium regime (photonic metamaterial). The dispersions of effective permittivity for periodic structures formed by plastics (ABS, black) were analytically obtained for both regimes. The study of the interaction of a plane wave and artificial cubic dielectric on a substrate parallelepiped to form a subwavelength terahertz beams (terajet) was performed. The results of numerical simulation of S-parameters of structure are discussed. The subwavelength beam waist of terajets about 0.39λ–0.41λ were obtained. The quality factor of terajets are discussed. The results may be applied for creation of methods to obtain subwavelength beams in the terahertz frequency range, and devices based on them. These investigations are opening new research lines such as mesoscale focusing devices for different sensing applications.