Applying perfectly absorbing thin screen to the 3D parabolic equation method

In this paper, perfectly absorbing thin screen is applied to the three-dimensional (3D) parabolic equation method in order to predict the propagation of electromagnetic waves in urban environments. The impedance boundary condition is used to represent the lossy nature of the ground and the Tukey window is adopted to attenuate the fields smoothly at the upper boundary without reflections. Besides, buildings are equivalent to a series of perfectly absorbing thin screens arranged along the direction of propagation and we use the split-step Fourier transform algorithm to solve the 3D parabolic equation. Finally, in order to validate the proposed method, several numerical simulations of a typical building on a flat ground are made and the results are compared with those in the literature. As a result, good agreements are observed.