far zone meaning in Chinese
远区
Examples
- Thirdly , one numerical stimulation method - fdtd ( fmite - difference time - domain ) and the transformation of near zone to far zone are introduced , and then the program is verified
接着介绍了时域有限差分法( fdtd )及其近场到远场的变换公式，并对自编的fdtd计算程序进行了验证。 - Using the simulation program , far zone radiation of tem - horn array is analyzed . the result of analysis proved that the mutual coupling between elements of array did not affect the main radiation wave of very much
应用这一模拟程序，分析了tem喇叭天线阵列轴上远场辐射，分析表明阵元间互耦对阵列轴上远场主辐射波形影响不大。 - In order to validate the feasibility of the novel algorithm , ultrawide band pulse wave is used as incident wave . computational domains are limited by absorbing boundary condition . the transformation technique from near zone to far zone is used when the sampling spot is outside of the computational domains
时域成像技术以超宽带脉冲源作为入射波源，用吸收边界条件来界定计算域，而当采样点远离计算区域时，需要通过近?远场的转换技术把近场等效面上的信息转换到远场，本文采用简单而实用的柱面波外推法作为近?远场的转换方法，收到了较好的效果。 - 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。