冯乃星,张玉贤,郑宏兴,等. 基于矩阵指数法的双线性Z变换PML模拟FDTD地下探测与成像[J]. 电波科学学报,2021,36(4):579-588. DOI: 10.13443/j.cjors.2020051201
      引用本文: 冯乃星,张玉贤,郑宏兴,等. 基于矩阵指数法的双线性Z变换PML模拟FDTD地下探测与成像[J]. 电波科学学报,2021,36(4):579-588. DOI: 10.13443/j.cjors.2020051201
      FENG N X, ZHANG Y X, ZHENG H X, et al. Compact BZT-ME-PML for modeling FDTD subsurface sensing and imaging[J]. Chinese journal of radio science,2021,36(4):579-588. (in Chinese). DOI: 10.13443/j.cjors.2020051201
      Citation: FENG N X, ZHANG Y X, ZHENG H X, et al. Compact BZT-ME-PML for modeling FDTD subsurface sensing and imaging[J]. Chinese journal of radio science,2021,36(4):579-588. (in Chinese). DOI: 10.13443/j.cjors.2020051201

      基于矩阵指数法的双线性Z变换PML模拟FDTD地下探测与成像

      Compact BZT-ME-PML for modeling FDTD subsurface sensing and imaging

      • 摘要: 凭借矩阵指数技术,一套紧凑且高精度的基于双线性Z变换的复频率偏移完全匹配层(perfectly matched layer, PML)算法被提出截断时域有限差分问题,实现甚低频地下探测和甚高频地下成像的模拟. 正因为采用了该技术,所提出的算法呈现为紧凑的一阶微分矩阵格式,使得该算法能够在数学推导期间完全地避免进行卷积操作、公式重排、变量替换. 再者,所提出算法不仅可以灵活地截断任意材料(因为采用了电/磁通量本构关系式),而且能够高效地衰减隐失波以及减少电磁波相互作用过程中后期的反射,从而更好地模拟开域空间问题. 此外,在距离目标体更近的距离进行截断模拟时,所提出算法仍然可以维持较高的吸收性能,以至于更小的计算区域可以被采用于模拟三维地下探测与成像问题,从而节省了大量的内存和计算时间. 最后,地下探测与成像问题被应用到阐述所提出算法的有效性和精度.

         

        Abstract: Depending on the matrix exponential (ME) method, a compact and highly-accurate implementation of the perfectly matched layer (PML) with the complex-frequency-shifted (CFS) scheme based upon the bilinear Z-transform (BZT) technique is developed for modeling the finite-difference time-domain (FDTD) problems on the very low frequency (VLF) subsurface sensing and the very high frequency (VHF) imaging. By using ME method, the proposal becomes a compact first-order differential matrix form so that it can completely circumvent convolution operations, formula rearrangements, or variable replacements during mathematical derivations. Furthermore, the BZT-ME-PML can not only flexibly terminate arbitrary media because of adding the DB constitutive relation, but efficiently attenuate evanescent waves and decrease late-time reflections due to incorporating the CFS scheme. Besides, the BZT-ME-PML can maintain higher absorption performances when it comes closer to truncate the FDTD domain with targets so that smaller computational regions can be adopted for modeling 3D open-domain subsurface sensing and imaging cases, resulting in palpable improvements in memory requirement and CPU time. The numerical simulations on the subsurface sensing and imaging have been carried out to illustrate the validity and accuracy of the approach.

         

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