【作者】 闫二艳；

【导师】 孟凡宝；

【作者基本信息】 中国工程物理研究院 ， 无线电物理， 2009， 博士

【摘要】 在高功率微波(HPM)效应和电磁兼容(EMC)研究中,研究人员对窄脉冲耦合进入复杂封装体的问题非常感兴趣。本论文主要以随机矩阵理论、统计电磁学、随机平面波假说、量子力学和电动力学为理论基础,采用随机耦合模型(RCM)对波混沌腔体进行了系统分析。从理论和实验两方面对随机耦合模型开展了研究。然而作为一个新兴的研究领域,随机耦合模型在HPM效应、EMC、抗辐射加固等研究中的应用可以说刚刚起步,还有许多急待解决的问题。本文在对波混沌腔体进行系统分析的基础上,探讨了RCM在各种条件下的实用性。随机耦合模型是一个结合随机平面波假说和随机矩阵理论(Random Matrix Theory,RMT),用公式表示具有时间反演不变性系统(Time Reversal Symmetry, TRS)和不具有时间反演不变性系统(Broken Time Reversal Symmetry, BTRS)的阻抗、导纳和散射的统计模型。采用随机矩阵描述的波混沌腔体中的“归一化阻抗”、“归一化导纳”和“归一化散射”具有通用统计特性,且只与腔体的损耗有关系。RCM模型主要引入具有非统计特性的“辐射阻抗”来描绘耦合孔周围的详细信息,采用随机矩阵理论提供具有统计通用性的物理量来描述波混沌腔体,然后将两者结合起来复原整个波耦合进腔体的状态。本论文首先简要回顾了国内外HPM效应研究现状,并分析、对比了现有HPM效应研究方法的特点、使用范围和局限性,着重从效应目标的不确定性和效应过程的随机性出发,引入了随机耦合模型。接着对随机耦合模型的理论基础——随机矩阵理论、随机平面波假说、波混沌等进行了描述和分析。为了证明RCM的可靠性和实用性,特将计算机机箱作为微波混沌腔体进行了模拟仿真和实验研究。重点讨论了在计算机机箱内部不同状态下RCM的应用,获得如下主要结论：1.通过模拟仿真、实验研究和RCM计算研究发现：如果针对一系列相似对象(例如计算机机箱)的效应结果进行统计分析时,系统的效应评估主要建立在大量实验数据基础上的,采用传统的数值模拟和实验研究方法,传统的实验研究方法将需要大量的实验样本,而对各种相似效应目标进行数值仿真则比较耗时。如果采用RCM对系统进行分析,只需知道系统少量系统参量,就可以方便的给出感应电压(电流)的统计结果。2.对波混沌腔体进行数值仿真和实验研究发现：计算机机箱中的散射行为是波混沌散射,RMT计算的归一化阻抗与模拟(或实验)得到的归一化阻抗的统计特性一致；归一化阻抗和归一化导纳本征值实部、虚部的统计特性非常一致,且与系统的耦合无关,不会随着参考面的移动而改变；随着腔体损耗的增加,插入相移分布逐渐趋于均一分布；辐射阻抗结合随机矩阵理论可以快速还原已知系统的腔体散射矩阵。3.搭建了实验平台,通过实验测量系统关键部位感生电压(电流)的大小以验证RCM的实用性。结果表明：两者的统计结果趋势基本一致,且实验测量范围与RCM计算的频数出现最多的范围基本一致。在实验过程中注意到辐射散射过程的测量直接影响到最终的统计结果。RCM在统计电磁学、电磁兼容、抗辐射加固和HPM效应研究领域有重要的实用价值。然而RCM研究现阶段仍然处于初期研究阶段,为了让其早日成为一个通用研究工具,需要进行更深入的理论和实验研究。在以后HPM效应机理研究中,可以结合量子力学、统计电磁学等学科,以拓宽研究思路和方法。更多还原

【Abstract】 In the field of high-power microwave (HPM) effects and electromagnetic compatibility (EMC) study, researchers are much interested in the item of short-pulse coupling into the large complicated enclosures. In this dissertation, the random coupling model (RCM) was analyzed based on random matrix, statistical electromagnetism, plane-wave hypothesis, quantum mechanics and electrodynamics theory. The RCM was summarized by combination of the theory and the experiment research.However, as an emerging research area, the applications of RCM in HPM effect and the EMC research have just started. There remain many pressing problems to be solved. Based on systematic analysis in the wave chaotic cavity, applicability of RCM was discussed in practical conditions.The RCM is a stochastic model which makes use of the random plane wave hypothesis and random matrix theory to formulate a statistical model for the impedance, admittance and scattering properties of time reversal symmetry (TRS) and broken time reversal symmetry (BTRS) wave-chaotic systems. Moreover, these fluctuations are expected to be universal in their statistical description, which depends only upon the value of a single dimensionless cavity loss-parameter. The port-coupling characteristics were accurately quantified by the "radiation impedance". The cavity scattering is recovered by combination of cavity loss and "radiation scattering".Firstly, a brief review of the status of HPM effect research was presented in this dissertation. Then the characteristics, the scope of usage and limitations of the existing method of HPM effects were analyzed and compared. Focusing on the influence of the uncertainty of the target and the random process, the RCM was introduced. Secondly, theoretical basis of RCM were described and analyzed. In order to prove the reliability and practicality of RCM, simulation and experimental investigation using the computer box cavity as a microwave chaotic cavity were carried out. The applications of RCM in the computer box with different states were discussed. The main obtained conclusions are as follows:Some results were found through simulation, experimental research and RCM calculation. While statistical analysis with effect results from a series of similar object is carried out, experimental study on traditional methods will require a large number of experimental samples, and numerical simulations of similar targets are more time-consuming. However analysing the system with RCM can give a convenient statistical result of induced voltages simply with a small number of system parameters.The numerical simulation and experimental study on the wave chaotic cavity reveals that the scattering behavior within computer box is the chaotic scattering and agrees well between the simulations and experimental results for the normalized impedance and the RMT predictions. The statistical properties of normalized impedance and admittance eigenvalue real part and imaginary part agree each other well, and don’t change with the reference surface movement and depend only upon the cavity losses. With the increase of cavity loss, insertion phase shift distribution is becoming more and more homogeneous. The radiation impedance of the coupling port combined with the numerically generated normalized impedance z from random matrix theory can obtain an estimate of the non-universal system-specific scattering coefficient.Practicability of RCM has validated by measuring the magnitudes of induced voltages at key points within computer box. It shows that the two results are basically the same trend. The experimental scattering radiation measurement process directly affects the final results.In statistical electromagnetism, electromagnetic compatibility and HPM effects research field, the RCM has important practical value. However, study on RCM at this stage is still at a preliminary stage. In order to make it a general purpose research tool as soon as possible, it calls for more in-depth theoretical and experimental research. New methods and ideals should be exploited by combining the quantum mechanics with statistical electromagnetism in the field of HPM effects.更多还原