抄録
This paper is concerned with a finite volume time domain (FVTD) analysis of the electromagnetic wave (EM) scattering from a periodic roughsurface such as a building wall in connection with the ray tracing method (RTM). In the RTM analysis, we take account only of the conventional optical reflection which responds to the zero-th Bragg reflection. In this context the field estimation by the RTM analysis may exibit a poor accuracy when we cannot neglect the higher order Bragg recflections. In this paper, we investigate what conditions are needed in order to be able to ignore the higher order Bragg reflections for the RTM.