Uniform theory of diffraction

In numerical analysis, the uniform theory of diffraction (UTD) is a high-frequency method for solving electromagnetic scattering problems from electrically small discontinuities or discontinuities in more than one dimension at the same point. UTD is an extension of Joseph Keller's geometrical theory of diffraction (GTD) and was introduced by Robert Kouyoumjian and Prabhakar Pathak in 1974.