The Practical Behavior of Various Edge-Diffraction Formulas

The scalar knife-edge diffraction (KED) solution is a workhorse for RF and optics engineers who regularly encounter practical diffraction phenomena. However, the approximate, polarization-independent KED result is formulated in a way that does not provide direct physical insight. In this article, we demonstrate how the KED formula contains similar underlying physics to other more-rigorous half-screen diffraction solutions, allowing engineers to apply common geometrical theory of diffraction (GTD) formulations for all screen diffraction problems. The underlying geometrical behavior of the scalar KED solution sheds new light on these old problems, revealing why it is so useful for solving real-word problems in radiowave propagation.