Fdtd Method For Analyzing The Dielectric Waveguide And Dielectric Loaded Cavity Electromagnetic Mode Field Distribution

Finite-difference Time-domain(FDTD) method is one of the most developed electromagnetic method. It has been applied extensively, including in radiation, scattering, electromagnetic compatible and optoelectronics.In this paper, the principle of FDTD has been reviewed and some complementarity has been given. The general computing way of electromagnetic question with FDTD method was illustrated and field equations in anisotropic perfectly matched layer(APML) were derived.With FDTD method, the fields at every time steps could computed once for all, coupled with the discrete Fourier transform, it's easy to receive the cut-off frequency of every modes. Compared with other numerical method, facility of FDTD was distinctive for just one time computation for all. The cut-off characteristics of metal waveguide, loaded waveguide, resonator and loaded resonator were computed, and comparison with datas was given to illustrate of the applicability of FDTD method. Further more, the cut-off characteristics of unreported half loaded and anisotropically dielectric full loaded rectangular resonators was computed and analyzed with common program.When computing optical waveguide, because of the unbounded frame of object and the limitation of computing speed, we cut off the lattice with absorbing boundary which made of APML. Representative computational examples, the TEO, TE1 and TE2 fields-distribution of planar waveguide was calculated and an comparison with analytical solution was presented to validate the theory. For the engineering design, propagation of electromagnetic wave also can be achieved with FDTD method.