Numerical analysis for wave propagation in circular waveguide using cylindrical coordinate system-based FDTD method

Abstract

Several problems of electromagnetic fields can be solved by various numerical methods. One of the methods is finite-difference time-domain (FDTD) where in this work is addressed for modeling a hollow circular waveguide and its wave propagation analysis. Different from other FDTD methods which is usually based-on Cartesian coordinate system, in current paper the cylindrical coordinate system is employed as a basis for computation. The method in two- and three-dimension (2D and 3D) systems is employed to model a circular waveguide which has the radius of 50m and length of 100m. A sine wave modulated Gaussian signal with frequency of 3MHz is applied as a wave source for computation. To truncate the computation area, the second order absorbing boundary condition (ABC) is assigned at the outer side and the center of waveguide. From the numerical result, it shows that the amplitude of wave that propagates from the inner to the outer of waveguide decreases along the radius due to the grid size in cylindrical coordinate system based-FDTD method both in 2D and 3D systems.