一种射线跟踪信道仿真的电磁参数选取方法

为了满足未来无线通信中信道建模日益增高的精度需求,针对射线跟踪信道仿真中电磁参数难以准确确定这一实际问题,提出了一种射线跟踪信道仿真的电磁参数选取方法.该方法利用局部实测的无线电传播信息绘制出无线环境图,基于感知哈希算法快速对比实测与射线跟踪仿真的无线环境图,从而调整仿真环境中的电磁参数使仿真数据逼近测试结果.针对多种...     

Waveguide and resonator perturbation techniques measuring chiralityand nonreciprocity parameters of biisotropic materials

Waveguide and resonator perturbation techniques are considered for determining electromagnetic parameters of general biisotropic, or nonreciprocal chiral, materials. The bisotropic materials are the most general linear isotropic media, whose constitutive relations are governed by four complex material parameters. The material parameters of bisotropic media can be obtained through measuring the change in the propagation constant of waveguide modes or measuring the shift in the resonant frequency for resonators with perturbation techniques. To measure these parameters a method utilizing waveguides or cavity resonators with two degenerate modes is proposed     

跨谱段SAR散射中心多维参数解耦和估计方法

微波光子雷达发射大带宽跨谱段的信号,为目标的精细电磁特性描述和准确识别提供基础的同时,也亟需与之相应的大带宽大转角情况下的电磁模型参数提取方法。相比窄带条件,跨谱段信号数据量大,所含物理量信息维度高且复杂,大转角情况下距离和方位向耦合。该文提出跨谱段SAR散射中心多维参数解耦和估计方法,首先结合极坐标格式算法(PFA)和属性散射中心模型构造2维解耦波数域散射中心模型,再结合坐标下降法(CDA)将复杂的高维耦合参数估计方法简化为循环迭代的1维参数估计方法,有效降低字典维度和估计复杂度,并引入Hooke-Jeeves算法提高估计精度。最后根据各个散射中心的参数估计结果对它们的结构和位置进行识别,对仿真数据的处理实验验证了该文方法的有效性。     

基于测量数据的电磁环境分析软件开发

为了掌握电磁环境现状及发展趋势,提高电子信息系统的运用效率,采用数理统计和神经网络算法,对电磁环境测量数据进行归纳和总结。开发了电磁环境分析及预测软件,提供了关键电磁参数的建模方法,实现了对特定区域电磁环境发展变化情况的预测,为电子信息系统应对复杂电磁环境挑战提供了技术支撑。     

Simultaneous Determination of Complex Permittivity and Permeability of Columnar Materials With Arbitrarily Shaped Cross Section

An effective simultaneous evaluation method for the complex permittivity and permeability of lossy materials is proposed by applying it to an arbitrarily shaped cross-sectional post placed in a rectangular waveguide. We use one sample and only measure S ₂₁ parameters for two different locations of the sample. The measurement of complex reflection parameter S ₁₁ is not required in this evaluation method. The scheme of electromagnetic field analysis for the evaluation is based on the extended spectral-domain approach combined with the mode-matching method, which is accurate and efficient, and can be flexibly used for the iterative fitting operation for the estimation of material parameters. Sample preparation and setting is significantly easier in this method compared to conventional methods. The error caused by deviations in the setting of a sample is investigated. The estimated values for the sample material by this procedure show good agreement with the results obtained using the conventional method over the X-band.     

New frequency-dependent parametric modeling of dielectric materials

The recent increase in the use of electromagnetic (EM) waves raises more and more concern about the impact of EM radiation. Dielectric properties of materials are important indications of the depth of EM propagation and dispersion. This led to substantial research on the parametric modeling of dielectric properties of materials. In this paper, such modeling of material is studied for frequencies up to 100 GHz. The new model proposed was developed to describe the variation of dielectric properties of dielectricity as a function of frequency using experimental results on dielectric dispersion. Approximate modeling of electrical parameters can be very useful in that it allows the engineer to avoid complex equations of conventional models. Specifically, this work analyzes the dielectric properties of human parts, water, soil and vegetation. The new model is proposed for those materials. The theoretical background on those materials was investigated and simulation results on complex permittivity, the attenuation and phase constants of wave, of each of those materials were performed to assess the accuracy of the new approximate model. This model has further enabled conclusions in terms of measurable biophysical parameters.     

THE MEASUREMENT OF COMPLEX PERMITTIVITY OF ANISOTROPIC DIELECTRICS BY MEANS OF AN ELECTROMAGNETIC OPEN RESONATOR

By applying the perturbation method and the complex-source-point theory, the theoretical research of measurement of complex permittivity of uniaxial anisotropic materials by means of an electromagnetic open resonator has been made, and the double refraction phenomenon due to anisotropy of measured dielectric materials has been quantitatively analyzed. Finally, measurements have been made on some single-crystal quartz specimens using an automated open resonator measurement system at 8mm band.     

一种用于器件模型参数提取的芯片测试数据的获取方法

半导体器件的建模及模型参数提取是电子设计自动化(EDA)领域的关键性工作。要提取器件参数,获取并处理复杂繁重的测量数据是前提条件,也是非常重要的一个环节,如何简单有效的提取并处理参数提取测试数据就显得格外重要。本文提出了简单易用的用于器件模型参数提取的测试数据的获取方法。实验证明,该方法可以有效的获取大量繁杂的测试数据,具有较高的精确度,而且简单易用,适合推广使用。     

An efficient crosstalk parameter extraction method for high-speedinterconnection lines

A proposal is presented for an effective extraction method for crosstalk model parameters of high-speed interconnection lines. In the extraction procedure, mutual capacitance and mutual inductance of the coupled interconnection lines are extracted based on S-parameter measurement, time-domain-reflectometry (TDR) measurement and subsequent microwave network analysis. The extraction method is useful for characterizing homogeneous guiding structures, where the propagation of coupled transverse electromagnetic (TEM) modes is supported. In contrast to previous extraction methods, the suggested procedure requires fewer on-wafer probing steps and does not need matched terminations in the test device for high-frequency probing. The extracted models can be readily used with simulation program with integrated circuit emphasis (SPICE) circuit simulation. The procedure can also be used for modeling the crosstalk in packaging structures and multichip modules (MCMs). The proposed procedure has been successfully applied to the crosstalk model extraction of on-chip interconnection lines. Crosstalk model parameters were obtained for different line structures, spaces, and widths. Finally, the validity and reliability of the extracted models were examined by comparing a SPICE circuit simulation using the extracted crosstalk model parameters with high-speed time-domain crosstalk measurement. A close agreement was observed in the amplitude and pulse shape between the simulation and the measurement, showing the accuracy and usefulness of the proposed extraction method     

电磁开腔测量各向异性媒质复介电常数

本文利用微扰原理和复数源点法,对电磁开腔测量单轴各向异性媒质复介电常数进行了理论研究,并且定量地分析了在测量中由于媒质的各向异性引起的双折射现象。最后利用一套八毫米电磁开腔自动测量系统对几种石英晶体样品进行了实际测量。     

设备级线缆强电磁辐照敏感度仿真分析

针对近年来复杂电磁环境中强电磁脉冲攻击,研究得出设备级强电磁辐照敏感度仿真分析方法。该方法采用3D电磁场仿真及2D电路仿真相结合的手段,通过建立几何模型、定义材料参数、添加负载及激励源、放置监测探头等步骤,最终仿真得出设备外壳内部及线缆上耦合电流的时域、频域特性。由仿真结果可知,设备内部及线缆上耦合的电压、电流在极短时间内即可达到具有破坏性的峰值,且其同时具备较宽的频谱,从而可对多种电子设备造成毁伤。因此,当电子设备处在复杂电磁环境强电磁脉冲攻击下,必须采取一定的强电磁保护措施。本仿真方法也可适用其他通用电子设备强电磁辐照敏感度仿真分析。     

Guided-wave and leakage characteristics of substrate integrated waveguide

The substrate integrated waveguide (SIW) technique makes it possible that a complete circuit including planar circuitry, transitions, and rectangular waveguides are fabricated in planar form using a standard printed circuit board or other planar processing techniques. In this paper, guided wave and modes characteristics of such an SIW periodic structure are studied in detail for the first time. A numerical multimode calibration procedure is proposed and developed with a commercial software package on the basis of a full-wave finite-element method for the accurate extraction of complex propagation constants of the SIW structure. Two different lengths of the SIW are numerically simulated under multimode excitation. By means of our proposed technique, the complex propagation constant of each SIW mode can accurately be extracted and the electromagnetic bandstop phenomena of periodic structures are also investigated. Experiments are made to validate our proposed technique. Simple design rules are provided and discussed.     

一种改进的频移键控调制信号盲识别方法研究

频移键控信号在民用和军事通信领域得到了广泛应用,因此对频移键控调制信号识别分析也具有重要意义。针对过去一些方法存在的问题,提出了一种改进的频移键控调制信号盲识别方法。新方法采用基于循环平稳特性的核心思想,能更好地适用于低信噪比下的复杂电磁环境。它可在无先验信息的情况下实现对频移键控信号特征的提取,是一种高效的识别方法,具有良好的稳健性和工程实用性。计算机仿真表明,新改进算法在较低信噪比条件下能达到较高的正确识别率,相比过去的方法性能更优。     

电大尺寸复杂结构腔体电磁散射的IPO/FEM混合法研究

该文将物理光学迭代法(IPO)的子域连接法与矢量有限元法(FEM)相结合,提出了一种新的混合方法用于分析计算电大尺寸复杂结构腔体目标的电磁散射特性。对于腔体内部适合用高频方法处理的部分采用IPO方法分析;对于具有复杂结构和材料特性的部分,采用矢量有限元法进行研究,利用交界面上的连续性条件实现这两种方法的耦合。为了验证理论模型的正确性,该文对某一矩形空腔及底部加载金属台阶的腔体进行了分析,计算结果与文献数据以及用时域有限差分法所得结果一致,并具有很好的收敛效果。在此基础上,对底部加载介质层的复杂结构腔体进行了分析计算,结果表明这种混合方法对于分析电大尺寸复杂结构腔体的散射特性是行之有效的。     

Transient analysis of microstrip line on anisotropic substrate inthree-dimensional space

The authors describe how anisotropy, with the permittivity tensor involving off-diagonal elements, may be generally formulated by Bergeron's method. The formulation is discussed for the propagation characteristics of single and parallel striplines on a sapphire substrate with tilted optical axis. To show the distinctive influence of anisotropy on the coupling property between lines, a parallel-line-type directional coupler on such a substrate is analyzed     

测量糊状物质复介电常数的级联网络分解法

提出了测量糊状物质复介电常数的级联网络分解法。先采用标量检测矢量变换法测出三个网络的散射参数,再用两种分解计算法求得糊状物样品的散射参数,最后用奇偶模法求得复介电常数。文中给出了三种糊状物的测试结果及误差分析结果。文中提出的方法也可用于测试粉末状材料、薄板材以及材料的高温测试及低温测试。     

基于时间门方法的随机耦合模型在复杂腔体电磁预测中的应用

利用随机耦合模型(random coupling model,RCM)预测复杂腔体电磁效应时,通常要通过测量辐射阻抗来实现,但实验过程中满足混沌腔体以及耦合通道的腔体加工、实验过程模拟等条件要求较高,且实验步骤繁琐.为了克服上述问题,文中采用时间门方法(time gating method,TGM),通过对散射参数进行...     

Analysis of high-speed interconnects in the presence ofelectromagnetic interference

This paper describes an efficient algorithm based on moment-matching techniques for simulation of high-speed circuits in the presence of electromagnetic interference (EMI). The proposed method is based on the recently developed complex frequency hopping (CFH) technique for interconnect analysis. The new technique is useful for susceptibility analysis and is two to three orders of magnitude faster than conventional simulation techniques. In addition, it can be extended to the analysis of interconnects with frequency-dependent parameters and nonlinear terminations     

用于电磁散射分析的积分方程快速直接求解法研究及进展

介绍了一系列用于电磁散射分析的积分方程快速直接求解方法,旨在显著缓解或避免积分方程迭代求解收敛缓慢甚至不收敛的问题,为积分方程提供一个快速稳定的数值求解手段.文中详细介绍了快速直接求解方法的优点、应用以及国内外的研究动态;重点讨论了几种不同的方法,分别为分级矩阵（hierarchical matrices,-matrices）以及分级非对角低秩矩阵（hierarchically off-diagonal low-rank matrices,HODLR）,包括每种方法的构建以及分解求逆方式;对各个方法的优缺点展开了进一步讨论;给出了各个方法的分解以及内存复杂度和复杂飞机模型的电磁散射分析数值算例来证明各个方法的效率和精度.最后,对快速直接求解方法当前仍然存在的主要挑战和可能的策略进行了简略的讨论以及展望.     

含各向异性介质衬底频率选择表面的直线法分析

运用直线法对一以单轴各向异性介质层为衬底的频率选择表面(FSS)进行了分析,考虑到介质层的各向异性,文中对直线法的常用方式作出了一定的修改,并详细介绍了整个方法实现过程。最后,对几套不同介电参数的FSS进行了计算,考虑了介质衬底的各向异性对FSS电磁特性的影响。