共查询到13条相似文献,搜索用时 109 毫秒
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为了能够快速有效地求解电大复杂腔体(微波混沌腔)的电磁耦合问题, 文中采用统计电磁学方法研究了该类腔体电磁散射的统计特征. 首先, 根据天线辐射理论, 利用电磁场的本征模展开式建立了腔体耦合输入阻抗表达式. 其次, 利用波动混沌理论和概率统计方法进一步推导出了微波混沌腔的随机耦合模型. 该方法简单并且可以直接推导出三维模型. 最后, 构建了一个三维Sinai微波混沌腔并进行数值仿真实验, 其仿真实验结果与随机耦合模型计算结果的统计特征基本一致. 重要的是, 该模型与复杂腔体的细节特征无关, 能够快速有效地预测微波混沌腔的敏感耦合问题.
关键词:
统计电磁学
微波混沌腔
输入阻抗
随机耦合模型 相似文献
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针对微波脉冲激励下复杂屏蔽腔体内部电路耦合电磁量计算的问题,建立了一个微波混沌腔体,通过测试获取了含内部电路的腔体辐射和辐射散射参数,利用随机耦合模型(RCM),对干扰脉冲能量进行了归一化处理,计算分析了微波脉冲宽度、脉冲间隔、脉冲数目以及腔体损耗因子对目标点感应电磁量统计分布的影响。计算结果表明:脉冲干扰下电路目标点耦合电磁量强于功率源激励;在脉冲能量一定的条件下,目标点耦合电磁量与微波脉冲的宽度、间隔和数目的变化均呈现一定的谐振特性,且单脉冲激励对电路的影响明显强于多脉冲。与此同时,实验还研究了电路易受电磁干扰的目标点的确定方法。 相似文献
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Pierre Nazé 《Journal of statistical physics》2018,171(3):434-448
Copula modeling consists in finding a probabilistic distribution, called copula, whereby its coupling with the marginal distributions of a set of random variables produces their joint distribution. The present work aims to use this technique to connect the statistical distributions of weakly chaotic dynamics and deterministic subdiffusion. More precisely, we decompose the jumps distribution of Geisel–Thomae map into a bivariate one and determine the marginal and copula distributions respectively by infinite ergodic theory and statistical inference techniques. We verify therefore that the characteristic tail distribution of subdiffusion is an extreme value copula coupling Mittag–Leffler distributions. We also present a method to calculate the exact copula and joint distributions in the case where weakly chaotic dynamics and deterministic subdiffusion statistical distributions are already known. Numerical simulations and consistency with the dynamical aspects of the map support our results. 相似文献
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STATISTICAL ENERGY ANALYSIS OF COUPLED PLATE SYSTEMS WITH LOW MODAL DENSITY AND LOW MODAL OVERLAP 总被引:1,自引:0,他引:1
C. HOPKINS 《Journal of sound and vibration》2002,251(2):193-214
Finite element methods, experimental statistical energy analysis (ESEA) and Monte Carlo methods have been used to determine coupling loss factors for use in statistical energy analysis (SEA). The aim was to use the concept of an ESEA ensemble to facilitate the use of SEA with plate subsystems that have low modal density and low modal overlap. An advantage of the ESEA ensemble approach was that when the matrix inversion failed for a single deterministic analysis, the majority of ensemble members did not encounter problems. Failure of the matrix inversion for a single deterministic analysis may incorrectly lead to the conclusion that SEA is not appropriate. However, when the majority of the ESEA ensemble members have positive coupling loss factors, this provides sufficient motivation to attempt an SEA model. The ensembles were created using the normal distribution to introduce variation into the plate dimensions. For plate systems with low modal density and low modal overlap, it was found that the resulting probability distribution function for the linear coupling loss factor could be considered as lognormal. This allowed statistical confidence limits to be determined for the coupling loss factor. The SEA permutation method was then used to calculate the expected range of the response using these confidence limits in the SEA matrix solution. For plate systems with low modal density and low modal overlap, relatively small variation/uncertainty in the physical properties caused large differences in the coupling parameters. For this reason, a single deterministic analysis is of minimal use. Therefore, the ability to determine both the ensemble average and the expected range with SEA is crucial in allowing a robust assessment of vibration transmission between plate systems with low modal density and low modal overlap. 相似文献