Finite conductivity uniform GTD versus knife edge diffraction in prediction of propagation path loss

The prediction of effects of intervening terrain on the propagation of high frequency electromagnetic waves has important applications with respect to the evaluation of communication links and low altitude radar performance. In the present investigation the frequency range from 100 MHz to 10 GHz is considered. The Fresnel knife edge diffraction method proposed by Schelleng et al. (1933) is still widely employed for intervening terrain which has one dominant diffracting ridge. The diffracting ridge can also be approximated as a wedge. Keller (1962) has considered a solution to wedge diffraction which serves as a canonical problem in the geometrical theory of diffraction (GTD). The current investigation has the objective to show that, with a minor increase in computation effort, wedge diffraction can be used to obtain path loss predictions which agree with knife edge diffraction for the cases where it is valid, and be significantly more accurate where it is not.