Application of moving window FDTD to prediction of path loss over irregular terrain

Abstract

The full wave electromagnetic calculation method that is most efficiently applied to electrically large problems is the Finite Difference Time Domain (FDTD) method. FDTD offers several advantages over the commonly used ray and PE methods. It is full wave, so that the approximations and assumptions needed for application of PE and ray methods do not limit its accuracy. It call include all of the pertinent information available for the propagation path, including terrain profile, terrain permittivity and conductivity, vegetation features, and atmospheric conditions. The FDTD mesh, assuming a uniform atmosphere, need be only long enough (the dimension along the propagation path) to contain the dispersed pulse, and high enough to include the terrain profile and a few Fresnel zones above the highest elevation.