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FD—TD法计算色散媒质中埋入异常体的电磁散射 总被引:5,自引:3,他引:2
本文论述了FD-TD法用于计算地下浅层目标的电磁散射问题。推出了Debye型色散媒质中FD-TD法的迭代公式和吸收边界条件。通过将FD-TD法计算的结果与其它结果相比较,证实了该方法计算有耗媒质中电磁场问题的有效性。对瞬态脉冲在色散媒质中的传播特性进行了讨论。分别计算了典型地下目标的散射波形和波形堆积图。 相似文献
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本文提出了修正的时域有限差分法(FDTD)来分析计算色散媒质中瞬变场问题,并采用普郎尼近似法使时域卷积可转化为违推计算,是充分利用现代计算机技术解决时域和宽带电磁场问题的一种有效手段。同时运用此方法对色散媒质中及色散媒质覆盖的导体目标瞬时域散射场进行了计算和分析,直观可靠地反映了其特性,并与传统的(非色散)FDTD方法计算的结果进行了比较,差别是显而易见的,为此必须重视色散媒质对瞬变场分析的影响。 相似文献
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N阶色散媒质的瞬态散射特性 总被引:3,自引:2,他引:1
本文提出了N阶色散媒质瞬态特性的时域分析方法,结合Z变换对常规的时域有限差分(FDTD)法进行了修正,改进后的FDTD法能分析和与频率有关的电磁场问题,具有方法简洁、易实现等优点。为验证此方法的有效性和可靠性,对N阶色散媒质的反向系数进行了分析与计算,并与已知的解析结果进行了比较,同时,采用此时域方法对N阶色散媒质和导体覆盖N阶色散媒质散射场进行了计算和分析。 相似文献
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本文首先利用三维FDTD法对集中电阻加载圆柱形偶极天线的近地面辐射特性进行了计算,给出了天线上电流波形并分析了加载电阻和有耗媒质参数等因素对电流波形的影响;分析并计算了天线“方向图”及其随天线高度和媒质参数变化的规律。其次,利用色散媒质中2.5维FDTD法迭代公式,模拟计算了地下目标雷达回波电平图,并与实际探测结果进行了对比,二者具有较好的一致性;分析了色散媒质参数对雷达探测深度的影响。 相似文献
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Fang Guangyou Zhang Zhongzhi 《电子科学学刊(英文版)》1996,13(3):267-274
The time-domain ElectroMagnetic(EM) scattering by buried objects in dispersive media is calculated with FD-TD method. The FD-TD formula in Debye dispersive media (both the complex permeability and the complex permittivity are described by Debye equations) are deduced, and the absorbing boundary condition is given. The validity of FD-TD method in lossy media is verified through comparing the FD-TD's results and the other ones. The propagation of transient pulses in dispersive media is studied in detail. The scattering pulses and the wiggle traces for typical buried objects are given. 相似文献
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本文利用FD-TD法分析了埋了埋地目标对基带脉冲波的电磁散射问题。在推出有耗媒质中FD-TD法代公式和吸收边办条件的基础上,对基带脉冲波在有耗媒质中的传播特性和埋地目标的电磁散射特性分别进行了较为详细地讨论。给出了部分目标的回波堆积图,并对探地雷达的探测性能与媒质特性、目标特性的关系进行了分析。 相似文献
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脉冲探地雷达的模拟计算 总被引:1,自引:0,他引:1
本文在给出Debye型色散媒质中2.5维时域有限差分法(2.5D-FDTD法)迭代公式的基础上,对无载频脉冲波在不同色散媒质中的传播特性进行了计算,分析了脉冲产生畸变的原因,并提出对部分畸变脉冲进行整形的方法。分别对地下单体目标和群体目标的雷达回波电平图进行了模拟计算,并与实际无载频脉冲探地雷达的探测结果进行比较,二者有较好的一致性,证实了本文所给计算公式的正确性。另外,还分析了土壤参数对雷达探测深度和分辨率的影响。 相似文献
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This paper presents a newly developed high-order discontinuous Galerkin time-domain (DGTD) method for solving Maxwell's equations in linear dispersive media with UPML boundary treatment. A unified formulation is derived for linear dispersive media of Debye type and the artificial material in the UPML regions with the help of auxiliary differential equations. The DGTD employs finite-element-type meshes, and uses piecewise high-order polynomials for spatial discretization and Runge-Kutta method for time integrations. Arbitrary high-order accuracy can be obtained for scattering of various objects in dispersive media. After validating the numerical convergence of the DGTD method together with the second-order Yee's scheme, we apply this new method to the ground-penetrating radar for the detection of buried objects in a lossy half space. 相似文献
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A weakness of the finite-difference-time-domain (FDTD) method is that dispersion of the dielectric properties of the scattering/absorbing body is often ignored and frequency-independent properties are generally taken. While this is not a disadvantage for CW or narrowband irradiation, the results thus obtained may be highly erroneous for short pulses where ultrawide bandwidths are involved. In some recent publications, procedures based on a convolution integral describing D(t) in terms of E(t) are given for media for which the complex permittivity ∈*(ω) may be described by a single-order Debye relaxation equation or a modified version thereof. Procedures are, however, needed for general dispersive media for which ∈*(ω) and μ*(ω) may be expressible in terms of rational functions, or for human tissues for which multiterm Debye relaxation equations must generally be used. The authors describe a new differential equation approach, which can be used for general dispersive media. In this method D(t) in terms of E(t) by means of a differential equation involving E, and their time derivatives. The method is illustrated for several examples 相似文献
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时域有限差分(FDTD)计算方法,已经被应用在解由飞秒脉冲激光器激励的THz电磁场辐射的Maxwell方程中,文中介绍了一种德拜模型,此德拜模型方法能准确地在一个较宽的频率带上,描述许多类型的生物组织.通过此模型,分析了THz脉冲通过色散介质时的传播情况.并经过对比说明THz成像(TPI)在物品检测,癌症判断以及其他应用的可能性. 相似文献