CAJ | 학술논문

基于线性插值的方法提出了一种适用于交替方向隐式时域有限差分法(ADI-FDTD)的吸收边界条件,该边界条件能够在ADI-FDTD方法中改善边界反射性能.首先,对由截断误差和相速估计误差引起的此吸收边界条件的反射进行了分析和推导.通过理论分析,说明了基于相速估计和非均匀网格的对此吸收边界改进方法能够改善边界条件的反射特性.然后进行了矩形波导情况下该吸收边界条件的数值仿真.最后给出了数值仿真结果,并通过对有无相速估计下吸收边界条件反射系数比较、对均匀和非均匀网格处理下吸收边界条件反射系数的比较,以及对在不同时间步长下吸收边界条件反射系数变化的分析,说明了该吸收边界条件及其改进方法对ADI-FDTD方法中的边界反射性能有很好的改善效果.
기우선성삽치적방법제출료일충괄용우교체방향은식시역유한차분법(ADI-FDTD)적흡수변계조건,해변계조건능구재ADI-FDTD방법중개선변계반사성능.수선,대유절단오차화상속고계오차인기적차흡수변계조건적반사진행료분석화추도.통과이론분석,설명료기우상속고계화비균균망격적대차흡수변계개진방법능구개선변계조건적반사특성.연후진행료구형파도정황하해흡수변계조건적수치방진.최후급출료수치방진결과,병통과대유무상속고계하흡수변계조건반사계수비교、대균균화비균균망격처리하흡수변계조건반사계수적비교,이급대재불동시간보장하흡수변계조건반사계수변화적분석,설명료해흡수변계조건급기개진방법대ADI-FDTD방법중적변계반사성능유흔호적개선효과.
With the linear interpolation method, an improved absorbing boundary condition(ABC) is introduced and derived, which is suitable for the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method.The reflection of the ABC caused by both the truncated error and the phase velocity error is analyzed.Based on the phase velocity estimation and the nonuniform cell, two methods are studied and then adopted to improve the performance of the ABC.A calculation case of a rectangular waveguide which is a typical dispersive transmission line is carried out using the ADI-FDTD method with the improved ABC for evaluation.According to the calculated case, the comparison is given between the reflection coefficients of the ABC with and without the velocity estimation and also the comparison between the reflection coefficients of the ABC with and without the nonuniform processing.The reflection variation of the ABC under different time steps is also analyzed and the acceptable worsening will not obscure the improvement on theabsorption.Numerical results obviously show that efficientimprovement on the absorbing performance of the ABC is achieved based on these methods for the ADI-FDTD.