An examination of the Fourier split-step method of representing electromagnetic propagation in the troposphere

The estimation of the electromagnetic propagation around a smooth spherical Earth in anomalous atmospheric conditions in the troposphere using Fourier split-step method is studied. The source of errors of Fourier split-step method and errors due to reducing the exact Helmholtz equation to the parabolic wave equation are reviewed. A quantitative measure for the accuracy of the numerical results is proposed. Optimization of the quantization parameters for accurate representation of electromagnetic propagation is investigated. The method is illustrated on different values of frequency, polarization, antenna pattern, antenna height, maximum angular frequency and range dependent refractivity. Optimal parameters are subsequently discussed. Finally, the region of validity is investigated numerically by comparison with the exact models.