Combination of the Improved Diffraction Nonlocal Boundary Condition and Three-dimensional Parabolic Equation Decomposed Model for Predicting Radiowave Propagation

Diffraction nonlocal boundary condition is one kind of the transparent boundary condition which is used in the Finite Difference (FD) Parabolic Equation (PE). The biggest advantage of the diffraction nonlocal boundary condition is that it can absorb the wave completely by using of one layer of grid. However, the computation speed is low because of the time consuming spatial convolution integrals. To solve this problem, the recursive convolution and vector fitting method are introduced to accelerate the computational speed. The diffraction nonlocal boundary combined with these two kinds of methods is called as improved diffraction nonlocal boundary condition. Based on the improved nonlocal boundary condition, it is applied to Three-Dimensional Parabolic Equation (3DPE) decomposed model. Numeric computation results demonstrate the computational accuracy and the speed of this three-dimensional parabolic equation decomposed model combined with the improved diffraction nonlocal boundary condition.