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The flexibility of the integral equation (IE) method is limited by the available numerical solutions with uniform‐grid schemes. In this paper, a general numerical solution of the IE is presented to predict long‐range low‐frequency (LF) groundwave propagation over irregular terrain. The general numerical solution is re‐derived with the aid of Legendre–Gauss quadrature and interpolation quadrature. The great advantage of the resulting algorithm is that it can freely use non‐uniform grid sizes in the computation area without loss of accuracy. Numerical results in two surface types, including triangular mountain and actual terrain are used to demonstrate the performance of the presented algorithm. Furthermore, it is ascertained that the non‐physical perturbations at long propagation ranges in the IE predictions are caused by the inherent uniform‐grid schemes of the numerical solution rather than the several approximations in the derivation of the IE form. [ABSTRACT FROM AUTHOR]

We previously developed a tri-diagonalized finite-difference time-domain (FDTD) algorithm based on the weighted Laguerre polynomials (WLPs) for modeling wave propagation in magnetized plasma. The algorithm demonstrated dramatic CPU time reduction in comparison with the original WLP-FDTD algorithm. However, a splitting error was caused owing to the additional perturbation term. In this paper, an iterative scheme is introduced to the tri-diagonalized WLP-FDTD algorithm to further reduce the splitting error. Numerical example shows the accuracy and effectiveness of the proposed algorithm. [ABSTRACT FROM PUBLISHER]

A perfectly matched layer (PML) with complex-frequency-shifted (CFS) constitutive parameters is introduced to the alternating-direction-implicit finite-difference time-domain (ADI-FDTD) method in cylindrical grids. The new CFS-PML is based on complex stretching methodology and implemented using bilinear transform. Numerical results show the effectiveness of the proposed implementation. [ABSTRACT FROM PUBLISHER]