【作者】 朱占平；

【导师】 钱宝良； 王弘刚；

【作者基本信息】 国防科学技术大学 ， 电子科学与技术， 2011， 博士

【摘要】 高功率微波与目标耦合效应研究是高功率微波应用与电子学系统加固领域的重要课题。本论文旨在研究微波与带缝腔体及基本电路的作用过程,在理论分析、数值模拟、微波注入实验的基础上,研究了微波与带缝腔体耦合、电路耦合及其电路传输效应问题,探索了一种系统研究和评估腔体封装系统微波效应的方法,对深入理解微波与带缝腔体及基本电路系统的相互作用具有重要意义。本文的主要研究内容和创新点有:1、对不同孔缝及孔缝阵列腔体的微波耦合特性进行了理论分析,得到了描述这些耦合特性的解析表达式,讨论了提高带缝腔体屏蔽性能的方法。首先利用互补天线理论,结合时域有限差分方法的数值模拟,分析了矩形、圆形、圆环、介质填充孔缝以及孔缝阵列的共振增强因子及共振耦合带宽与其尺寸和位置的关系。该理论适用于任意系统的带孔缝封装耦合特性的分析,所得到的耦合特性结论为系统的封装设计提供了依据。在此基础上利用空气离子化模型分析了矩形窄缝的击穿过程,推导了等离子体孔缝建立时间的表达式,详细讨论了微波波形和微波参数与等离子体孔缝的相互作用过程,并从物理上解释了矩形孔缝击穿时的尾融和频率偏移现象。微波在等离子体中的尾融现象为高功率微波窗口击穿的判断提供了理论参考,而利用尾融效应可制作等离子体限幅器,这是电子设备的高功率微波防护的一条可行途径。介质加载孔缝的耦合特性分析表明在模拟的情况范围内腔体的屏蔽性能最大可以提高6dB,介质加载是孔缝腔体耦合防护的另一条可行途径。最后总结了带缝腔体的耦合传输函数,完善了带封装系统的腔体耦合结构拓扑分析。2、对微波与电路的耦合特性进行了理论分析,利用得到的理论模型讨论了耦合过程中物理现象,为电子系统的电磁防护研究提供了参考依据。一方面利用等效传输线模型对同轴电缆及电子线路单线的耦合特性进行了理论研究,得到同轴电缆及电子线路单线的耦合防护的重点频带。另一方面在求解了等离子体覆盖电路的等效电路参数的基础上,利用拉普拉斯变换分析了沿线分布等离子体的产生对微波耦合和传输的影响,理论得到的频率漂移现象及随机加热为电路的防护提出了新的要求。3、采用理论分析、电路模拟和微波注入实验相结合的方法,研究了分别以74HC04和74LVCU04A两种芯片为核心的反相器基本缓冲及数模转换电路的微波效应问题,弥补了目前元器件和复杂电路系统的微波效应机理研究的不完整性,拓展了前人的研究成果。详细分析了线性干扰、非线性扰乱和损伤三个等级效应的微波有效功率阈值及其随频率、脉冲宽度和重复频率的影响,给出了线性干扰的电路放大倍数,通过反相器闩锁过程对非线性扰乱进行了机理分析,并利用元器件热积累模型推导了器件损伤与微波脉宽关系式。典型的实验结果是,在固定环境温度的注入实验中,有效注入功率大于26dBm,频率在3GHz以下的微波均可使设计的74HC04效应电路的噪声容限下降40%以上;有效注入功率大于23dBm,频率在3GHz以下的微波均可使设计的74LVCU04A效应电路的噪声容限下降40%以上;注入微波使非线性扰乱强度达到10%时的有效功率阈值比使线性干扰强度达到40%时的有效功率阈值大6-8dB。相同线性干扰或非线性扰乱强度的注入有效功率阈值近似随频率的提高而增大。在研究注入微波波形对微波效应的影响的实验中发现线性干扰随脉冲宽度的变化没有明显变化,而非线性干扰阈值随注入微波信号脉宽变化明显,拐点约为40-70ns不等,与反相器中的CMOS器件寄生三级管的导通电流积累有关。另一方面,注入微波的重复频率对微波线性干扰及非线性扰乱效应阈值影响很小。4、对微波注入实验结果进行了统计分析,证明了微波注入实验方案与实验结论的合理性,提出并研究了带缝腔体封装基本电路的微波效应的评估方法。数据处理主要包括无显著影响的参数的效应结果的统计检验、信号干扰规律的线性回归拟合检验、未知规律曲线的测量点置信区间估计、实验样本容量的选取以及损伤效应的“总体作用概率置信下限”分析,得到了确保实验可靠性和数据可信度的方法,同时利用网络算法对带孔缝金属封装的基本电路多层结构的微波耦合特性进行了分析,总结了系统传输函数矩阵。这些注入实验分析及数据处理的方法为电子系统微波注入效应实验提供了一条可行的技术方案。更多还原

【Abstract】 The investigation of the interaction between high power microwave and the electronic system is an important topic in the area of the applications of high power microwave and the reinforcement of the electronic systems. The effects of microwace on cavity with slots and basic circuit are investigated by theoretical analysis, numerical simulation, and microwave injection experiment. The process of microwave-slot coupling in the cavity, microwave coupling into circuit, and the microwave effects on circuit transmission are studied, and the model and evaluation of microwave effects on system with metal enclosure are also provided, which is helpful to expore the effects of microwave on cavity with slots and basic circuit. The details of invesitagtion are as follows:1. The coupling characteristics of the slot and array slot are investigated in detail in order to improve the shielding performance of the cavity with slots. With complementary antenna theory, the resonant frequency, the resonant and enhancement factor, and the resonant bandwidth are derived with slots being rectangular, circular, annulus, media packing, and array. The expressions have wide application in studing the coupling characteristics of any metal cavity with slots and the results are helpful to the design of the cavity of the system. Using the analysis of the procession of the air ionization in the narrow rectangular slot, the relation between the breakdown time and peak incident electric field is derived to explain the tail erosion effects and the frequency upshifts. The analysis results can be used to the investigation of the widnow breakdown of the high power microwave and the design of plasma limiter for preventing high power microwave. The shielding performance of the cavity is improved 6 dB by the media coating, which is another microwave protection method in the microwave-slot coupling. The systemic and overall analysis of microwave-slot coupling gives a strong support for the investigation of microwave effects on the electronic systems and the improvement of shielding performance of electronic systems.2. The microwave coupling into the circuit is theoretically studied. The coupling performance of cables and one-line print circuit are studied by using the equivalent transform line model, and the key bandwidth of the coupling frequency is derived. By using the Laplace transformation, the influence of the plasma on the microwave coupling and transmission is explored, indicating the frequency upshift of the microwave and the random heating phenomenon, which is a new challenge to electromagnetic compatibility of the electronic system.3. Based on the theoretical analysis, simulation and the experiment of microwave injection into the circuit, the microwave effects on the buffer and analog-digital converter circuit are investigated on the basic circuit level. The core chip of the ciruit is 74HC04 or 74LVCU04A inverter. The study is concentrated on the parameters of the injected microwave pulses, such as amplitude, carrier frequency, pulse width, and repetition frequency, changing the microwave effects on the circuit operation at three levels, which are linear interference, nonlinear disturbance, and damage effect. The analysis of the amplification gain of the circuit voltages, the process of the inverter shutting up and the relationship between the width of microwave pulse and power threshold of damage indicate the mechanism of linear interference, nonlinear disturbance, and the damage effect respectively. Under the conditions of the fixed temperature, the threshold of the effective injected microwave power for reducing the noise tolerance in the output signal by 40 % is 26 dBm for 74HC04 and 23 dBm for 74LVCU04A, when the carried frequency of injected microwave frequency is below 3GHz. The threshold of the effective injected microwave power for reducing the noise tolerance in the output signal by 50 % is 4 to 6 dBm, which is lower than that for reducing the sampling interval of the output signal by 10%, with which the response changes from the linear interference to the nonlinear disturbance. The threshold of the effective injected microwave power increases with the carrier frequency, which is similar to the linear interference and nonlinear disturbance. The threshold of the microwave effects on the circuit is almost independent to the repetition frequency of the injection microwave in linear disturbance regim. The threshold of nonlinear disturbance has a strong relation to the pulse width of the injection microwave, and the inflection point of the relation curves is about 40 to 70 ns, which is related to the current shutting up. The microwave effects on basic circuit are the extension to the study of the elementary device and the complex circuit.4. The results of injected microwave experiment are treated by the statistic analysis and the overall effects are studied by the effects analysis and evaluation. The statistic analyses, consisting of the statistic analysis on the no obvious influence variable, the fitted linear line analysis for the linear interference, the analysis of the believable region of measurement data, the analysis of the sample requirement of the experiment, and the analysis of the lower believable limit of probability of the completely destroying effect, making sure the reliability of injected microwave experiment results and giving a further improvement suggestion to the study of microwave effects on electronic system. The transmission functions matrix of basic circuit with cavity enclosure is studied by the theoretical analysis and network algorithm, which is useful for the high power microwave radiation experiment on the circuit.更多还原