On the accuracy of the complex image method

The far-field asymptotic expressions for the vector potential Green´s function of an infinitesimal vertical magnetic dipole (VMD), radiating above a half-space, are used to explain the failure of the standard CI method, when the source and observer are near to the interface, but separated by a large lateral distance. In these types of problems the field at the observation point is dominated by a lateral wave that is not modeled accurately by the standard Cl method. It is shown for the first time that by applying the Cl approximation process over a different path in the k/sub z0/ plane, the accuracy and robustness of the Cl method for such a problem geometry can be improved.