给出了时域非连续伽辽金(Discontinuous Galerkin Time Domain,DGTD)法的基本思想,从Maxwell方程出发得到弱解形式和矩阵方程,进一步给出了DGTD步进计算式.计算了空腔和填充谐振腔的谐振频率,并与解析结果相比较.算例表明在谐振腔计算中...给出了时域非连续伽辽金(Discontinuous Galerkin Time Domain,DGTD)法的基本思想,从Maxwell方程出发得到弱解形式和矩阵方程,进一步给出了DGTD步进计算式.计算了空腔和填充谐振腔的谐振频率,并与解析结果相比较.算例表明在谐振腔计算中DGTD可以达到很高的精度.展开更多
时域有限元方法(Finite Element Time Domain Method—FETD)是近几年发展起来的一种可用于分析复杂电磁问题的数值方法。它可以对目标的复杂几何结构和介质组成特性进行精确模拟,其分析结果比频域分析方法更具有直观性。文章基于FETD,...时域有限元方法(Finite Element Time Domain Method—FETD)是近几年发展起来的一种可用于分析复杂电磁问题的数值方法。它可以对目标的复杂几何结构和介质组成特性进行精确模拟,其分析结果比频域分析方法更具有直观性。文章基于FETD,分析了两种典型的微波电路—微带低通滤波器(Microstrip Lowpass Filter)和共面带状线(CPS)。展开更多
为了提高配电线路的安全可靠性并对线路防雷设计提供有价值的参考依据,基于非均匀传输线理论和Agrawal场线耦合模型,实现了一种用于求解非均匀多导体传输线场线耦合模型改进电报方程的单变量时域有限元(FETD)法,通过与双变量FETD法对比...为了提高配电线路的安全可靠性并对线路防雷设计提供有价值的参考依据,基于非均匀传输线理论和Agrawal场线耦合模型,实现了一种用于求解非均匀多导体传输线场线耦合模型改进电报方程的单变量时域有限元(FETD)法,通过与双变量FETD法对比,验证该方法的正确性。针对典型35 k V架空配电线路,计算了不同大地电导率和雷击距离条件下考虑导线弧垂的雷电感应电压,并分析了弧垂对雷电感应电压的影响机理。结果表明实现线路雷电感应电压的准确计算需要计及弧垂的影响。此外,比较了考虑弧垂、电晕和架设地线对雷电感应电压的影响,进一步说明了考虑导线弧垂的必要性。展开更多
时域离散伽略金法(Discontinuous Galerkin Time Domain,DGTD)是一种兼备时域有限元(FETD)网格剖分的灵活性和时域有限差分(FDTD)显式迭代特点的新兴算法。现有文献在非结构网格情形下相邻四面体公共面的判定方面缺乏简便的快速算法。...时域离散伽略金法(Discontinuous Galerkin Time Domain,DGTD)是一种兼备时域有限元(FETD)网格剖分的灵活性和时域有限差分(FDTD)显式迭代特点的新兴算法。现有文献在非结构网格情形下相邻四面体公共面的判定方面缺乏简便的快速算法。本文给出一种基于"空间投盒子"技术的四面体公共面快速判断方法。数值结果说明了本文算法的准确性和有效性。展开更多
电磁场时域计算方法由于一次计算可以获得目标的时域响应,结合傅里叶变换得到宽带信息等的优势越来越受到关注.本文介绍了近年来时域有限差分(finite-difference time-domain,FDTD)法和时域有限元(finite element time-domain,FETD)无...电磁场时域计算方法由于一次计算可以获得目标的时域响应,结合傅里叶变换得到宽带信息等的优势越来越受到关注.本文介绍了近年来时域有限差分(finite-difference time-domain,FDTD)法和时域有限元(finite element time-domain,FETD)无条件稳定算法方面的研究进展以及FETD算法的更新方案--时域非连续伽辽金(discontinuous Galerkin time-domain,DGTD)方法的新进展.展开更多
As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order elec...As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order electromagnetic wave equation. However, the PML boundary condition is difficult to apply in GPR Finite Element Time Domain (FETD) simulation based on the second order electromagnetic wave equation. This paper developed a non-split perfectly matched layer (NPML) boundary condition for GPR FETD simulation based on the second order electromagnetic wave equation. Taking two-dimensional TM wave equation as an example, the second order frequency domain equation of GPR was derived according to the definition of complex extending coordinate transformation. Then it transformed into time domain by means of auxiliary differential equation method, and its FETD equation is derived based on Galerkin method. On this basis, a GPR FETD forward program based on NPML boundary condition is developed. The merits of NPML boundary condition are certified by compared with wave field snapshots, signal and reflection errors of homogeneous medium model with split and non-split PML boundary conditions. The comparison demonstrated that the NPML algorithm can reduce memory occupation and improve calculation efficiency. Furthermore, numerical simulation of a complex model verifies the good absorption effects of the NPML boundary condition in complex structures.展开更多
In this paper,we propose a finite element time-domain(FETD)method for the Maxwell’s equations in chiral metamaterials(CMMs).The time-domain model equations are constructed by the auxiliary differential equations(ADEs...In this paper,we propose a finite element time-domain(FETD)method for the Maxwell’s equations in chiral metamaterials(CMMs).The time-domain model equations are constructed by the auxiliary differential equations(ADEs)method.The source excitation method entitled total-field and scattered-field(TF/SF)decomposition technique is applied to FETD method for the first time in simulating the propagation of electromagnetic wave in CMMs,based on which a unified ADE-FETD-UPMLTF/SF scheme is proposed to simulate the wave in CMMs.The following properties of CMMs can be observed successfully from the numerical experiments based on our method,i.e.,the ability of the polarization rotation,and the negative phase velocity.The amplitude of reflected wave can effectively be controlled by the physical parameters of CMMs.展开更多
文摘给出了时域非连续伽辽金(Discontinuous Galerkin Time Domain,DGTD)法的基本思想,从Maxwell方程出发得到弱解形式和矩阵方程,进一步给出了DGTD步进计算式.计算了空腔和填充谐振腔的谐振频率,并与解析结果相比较.算例表明在谐振腔计算中DGTD可以达到很高的精度.
文摘时域有限元方法(Finite Element Time Domain Method—FETD)是近几年发展起来的一种可用于分析复杂电磁问题的数值方法。它可以对目标的复杂几何结构和介质组成特性进行精确模拟,其分析结果比频域分析方法更具有直观性。文章基于FETD,分析了两种典型的微波电路—微带低通滤波器(Microstrip Lowpass Filter)和共面带状线(CPS)。
文摘为了提高配电线路的安全可靠性并对线路防雷设计提供有价值的参考依据,基于非均匀传输线理论和Agrawal场线耦合模型,实现了一种用于求解非均匀多导体传输线场线耦合模型改进电报方程的单变量时域有限元(FETD)法,通过与双变量FETD法对比,验证该方法的正确性。针对典型35 k V架空配电线路,计算了不同大地电导率和雷击距离条件下考虑导线弧垂的雷电感应电压,并分析了弧垂对雷电感应电压的影响机理。结果表明实现线路雷电感应电压的准确计算需要计及弧垂的影响。此外,比较了考虑弧垂、电晕和架设地线对雷电感应电压的影响,进一步说明了考虑导线弧垂的必要性。
文摘时域离散伽略金法(Discontinuous Galerkin Time Domain,DGTD)是一种兼备时域有限元(FETD)网格剖分的灵活性和时域有限差分(FDTD)显式迭代特点的新兴算法。现有文献在非结构网格情形下相邻四面体公共面的判定方面缺乏简便的快速算法。本文给出一种基于"空间投盒子"技术的四面体公共面快速判断方法。数值结果说明了本文算法的准确性和有效性。
文摘As a highly efficient absorbing boundary condition, Perfectly Matched Layer (PML) has been widely used in Finite Difference Time Domain (FDTD) simulation of Ground Penetrating Radar (GPR) based on the first order electromagnetic wave equation. However, the PML boundary condition is difficult to apply in GPR Finite Element Time Domain (FETD) simulation based on the second order electromagnetic wave equation. This paper developed a non-split perfectly matched layer (NPML) boundary condition for GPR FETD simulation based on the second order electromagnetic wave equation. Taking two-dimensional TM wave equation as an example, the second order frequency domain equation of GPR was derived according to the definition of complex extending coordinate transformation. Then it transformed into time domain by means of auxiliary differential equation method, and its FETD equation is derived based on Galerkin method. On this basis, a GPR FETD forward program based on NPML boundary condition is developed. The merits of NPML boundary condition are certified by compared with wave field snapshots, signal and reflection errors of homogeneous medium model with split and non-split PML boundary conditions. The comparison demonstrated that the NPML algorithm can reduce memory occupation and improve calculation efficiency. Furthermore, numerical simulation of a complex model verifies the good absorption effects of the NPML boundary condition in complex structures.
基金supported partially by the Science and Technology Development Fund,Macao SAR(0070/2019/A2)and National Natural Science Foundation of China,Grant No.11701598,Scientific Research Fund of Hunan Provincial Science and Technology Department(No.2018WK4006)NSFC Projects No.11771371,and Key Project of Hunan Education Department No.18A056.
文摘In this paper,we propose a finite element time-domain(FETD)method for the Maxwell’s equations in chiral metamaterials(CMMs).The time-domain model equations are constructed by the auxiliary differential equations(ADEs)method.The source excitation method entitled total-field and scattered-field(TF/SF)decomposition technique is applied to FETD method for the first time in simulating the propagation of electromagnetic wave in CMMs,based on which a unified ADE-FETD-UPMLTF/SF scheme is proposed to simulate the wave in CMMs.The following properties of CMMs can be observed successfully from the numerical experiments based on our method,i.e.,the ability of the polarization rotation,and the negative phase velocity.The amplitude of reflected wave can effectively be controlled by the physical parameters of CMMs.
