Prediction of VLF electric strength based on waveguide mode theory using GA

An equation which describes the propagation of the very low frequency(VLF) electromagnetic waves in the earth ionosphere waveguide is created based on waveguide mode theory. The eigenvalues of the equation i.e. the complex angles of wave incidence is obtained by genetic algorithm(GA). Then the electromagnetic fields in the waveguide are calculated. For perfectly conducting earth and perfectly reflecting ionosphere there is a gap between the numerical method of GA and the analytical method especially for higher modes. The simulation trails show that the GA method has a higher accuracy than the analytical method within 1000 km where the minimum field strength appears in the distance of about 500 km fron transmitter. The fields calculated from it have a closer approximation to the actual data so it can be uesd to predict the field strength of VLF waves in the propagation if the influence of atmospheric noise is not considered.