【作者】 李毅；

【导师】 袁乃昌；

【作者基本信息】 国防科学技术大学 ， 电子科学与技术， 2007， 博士

【摘要】 隐身与反隐身对抗是现代电子战的一个重要方面。雷达目标的电磁散射特性研究是设计开发隐身武器装备与反隐身雷达系统的基础。针对冲激雷达在反隐身领域的可能应用,以及基于自研的冲激雷达实验系统发射的脉冲信号特征,文章首先从理论预估和暗室测量两个方面研究了隐身目标的低频宽带电磁散射特性和时域电磁散射特性,然后在外场用冲激雷达试验样机进行了隐身目标的探测实验。理论预估包括电磁散射计算方法研究和雷达隐身目标电磁散射计算两部分内容。在电磁散射计算方法中,选用时域有限差分法(FDTD)及其并行算法作为主要的预估方法。在电磁计算方法研究中,首先介绍了FDTD的基本原理和一些关键技术,研究了基于面元模型的FDTD网格生成技术和基于FDTD网格模型的涂敷层网格生成技术。然后研究了可节省时间的交替方向隐式—时域有限差分(ADI-FDTD)。接着进一步研究了适合计算非磁化等离子体的基于分段线性电流密度递归卷积(PLJERC)的ADI-FDTD,适合计算磁化等离子体的电流密度卷积—时域有限差分(JEC-FDTD)。最后结合编程实践,给出了基于消息传递接口(MPI)的并行FDTD的一些关键技术,指出了JEC-FDTD与一般并行FDTD的不同:并行JEC-FDTD增加电流密度的迭代和相邻子域相应的电流密度数据和电场数据的交换。在雷达隐身技术中,论文研究了外形隐身,雷达吸波材料(RAM)隐身和新兴的等离子体隐身技术。探讨了它们的原理,实现隐身的方法。然后用FDTD计算了分别采用这些隐身技术的目标的电磁散射特性,得到了一些有价值的结论。在暗室测量方面,介绍了两套基于紧缩场暗室的频域和时域测量系统。然后利用频域和时域测量系统,测量了典型隐身目标的电磁散射特性,并与计算结果进行了对比分析。计算和测量结果都表明,隐身目标在低频区的隐身效果较差。在外场探测方面,介绍了冲激雷达系统的特点和自研的冲激雷达实验系统的构成,并利用该系统成功的进行了近距离和中远距离探测隐身目标的实验。这证实冲激雷达具有反隐身的潜力。更多还原

【Abstract】 The counterwork between stealth and anti-stealth is an important field in modern electronic war. Study of radar target’s electromagnetic scattering characteristics is the foundation to design stealth weapons and anti-stealth radar systems. In this dissertation, based on the potential of impulse radars to detect stealth targets, and the pulse signal’s character of an impulse radar test system designed by ourselves, firstly stealth targets’ wideband electromagnetic scattering characteristics in low frequency and electromagnetic scattering characteristics in time-domain are studied by using both theory prediction and chamber measurement, finally several outdoor experiments to detect stealth targets are performed by using the impulse radar experiment system.Theory prediction includes study on electromagnetic computing methods and electromagnetic scattering computation of radar stealth targets. Among lots of methods to predict electromagnetic scattering characteristics, the finite-difference time-domain (FDTD) method and its parallel mode are chosen as the primary method. In the part of study on electromagnetic computing methods, firstly basic principles of the FDTD and some key techniques are introduced. And the FDTD meshing technique based on facet models and the technique of producing coated grids based on the FDTD grids are put forward. Then, the alternating direction implicit finite difference time domain (ADI-FDTD) method is studied. The ADI-FDTD method is extended to dispersive media—isotropic plasma based on the PLJERC(Piecewise Linear JE Recursive Convolution) method. And the JEC-FDTD method for the magnetized plasma is studied. Then, according to author’s own programming practice, some key techniques of the parallel FDTD method based on MPI (Message Passing Interface) are provided. The difference between the parallel JEC-FDTD and the parallel FDTD has been pointed out. The parallel JEC-FDTD method increases current density iteration, and increases some current density datum and electric field datum exchange in the interface.Among the lots of radar stealth technique, shape-stealth, radar absorbing material (RAM) and developing plasma-stealth have been analyzed. Their principles and the stealthy methods have been researched. Then the electromagnetic scattering characteristics of stealth targets have been gotten by the FDTD method, and the valuable conclusions have been deduced.In the indoor measurement aspect, the systems of frequency domain and time domain are introduced. The electromagnetic scattering characteristics of the representative targets are measured by the systems. And the calculated results and the measured results are analyzed. The results indicate: stealthy abilities of stealth targets are weak in low frequency.In the outdoor detection aspect, the characteristics of the impulse radar system have been introduced. And our structure for the impulse radar experiment system has been provided. Then the experiments of detecting stealth targets in the short-range and in the long-range have been successfully performed. These show that the impulse radar has anti-stealth potential.更多还原