High-Frequency Techniques in Diffraction Theory: 50 Years of Achievements in GTD, PTD, and Related Approaches [Special section introduction]

As stated in the title, this special section of the IEEE Antennas and Propagation Magazine was conceived to celebrate 50 years since the publications of two fundamental scientific works: the paper by J. B. Keller, “Geometrical Theory of Diffraction,” Journal of the Optical Society of America, 52, 1962, pp. 116–130; and the book by P. Ya. Ufimtsev, Method of Edge Waves in the Physical Theory of Diffraction, Moscow, Soviet Radio, 1962 (in Russian).