空间步长 meaning in English
knot spacing
Examples
- Compared with the conventional finite - difference method on the fixed grid - size rectangular grids , the new method can be more cost - effective in complex models . numerical tests for both seismic modeling and reverse - time migration are performed on various theoretical models and a physical experiment
用该剖分方法得到的网格在各速度层内的空间步长是不同的，而全区域上的时间步长却近于恒定，因此在复杂模型上，本文方法的计算效率要高于传统的矩形网格差分方法。 - The conformal microstrip antenna with some unique character has been applied in many fields , especialy on speedy objects . in this paper , an efficient fdtd algorithm is introduced to analyse the microstrip antenna . firstly , the fdtd formula in descartes coordinate system and in cylindrical coordinate system are obtained from the time _ dependent maxwell equations using the yee algorithm in a calculating region where the dielectric parameters are independent of time and space . the choice of the space discretization units and the time discretization interval are discussed which are decided by the accuracy and stability respectively . the shape and setup of the excitation source are discussed too . the excitation source is chosen to be gaussian pulse in shape . secondly , the mur ' s first - order and second - order boundary condition are deduced in cylindrical coordinate system . the methods of transforming radiation fields from near zone to far zone in the frequency domain and in the time domain are presented when fdtd is applied to analyse the characteristics of far zone . finally , three kinds of microstrip antennas are analysed . they are a slot antenna that lies on a plane ground of a microstrip , a slot antenna that lies on a cylindrical ground of a microstrip and a microstrip line _ fed aperture coupled stacked rectangular patch antenna in cylindrical coordinate system
本文从麦克斯韦旋度方程出发，建立了笛卡儿坐标下无源空间中均匀无耗媒质的fdtd基本方程和圆柱坐标下无源空间中均匀无耗媒质的fdtd基本方程，详细讨论了fdtd法计算中时间步长和空间步长的选取原则以及激励源的类型和设置；推导了mur一阶和二阶边界条件在圆柱坐标下的差分格式；给出了在用fdtd法计算天线的远场辐射特性时必需采用的频域和时域近场远场变换技术；最后用fdtd法计算了平面微带缝隙天线、柱面共形微带缝隙天线和柱面共形微带层叠天线的输入阻抗和远区辐射场，并分析了天线的一些参数的变化对天线输入阻抗的影响，得出了一些有用的结论。