Experimental and Theoretical Validation for the Incremental Theory of Diffraction

Experimental and theoretical approaches to verify the validity of the incremental theory of diffraction (ITD) are considered. After providing a simple recipe for the application of the ITD, three geometries are examined for its validation. First, the ITD formulation of the diffraction from a perfect electric conductor (PEC) straight wedge is compared with the uniform theory of diffraction (UTD) and with measurement results. Second, the ITD formulation of the diffraction from a PEC disc is compared with measurement results and with the exact solution of a boundary value problem involving oblate spheroidal functions. Third, the ITD formulation of the diffraction from a hole in a PEC plane is compared with the exact solution of a boundary value problem involving oblate spheroidal functions. In particular, this is the first time that ITD results for diffraction from the disc and hole in a plane geometries are validated using exact solutions computed at a caustic. In all cases examined, very good agreement is found.