Plane wave diffraction by a large semicircular cylindrical boss

The diffraction of a plane wave by a large semicircular cylindrical boss on a plane of infinite extent has been studied by application of the Watson Transformation. Three cases are considered: plane ground wave incidence, vertically polarized oblique plane wave incidence, and horizontally polarized oblique plane wave incidence. The transformed solutions give physical meaning to the diffraction process by isolating each contribution. The results show the diffraction to be composed of three primary terms: "creeping waves", waves reflected from the boss, and waves reflected from the ground plane. Numerical calculations are made comparing the classical "harmonic series" with the transformed solution. These calculations show good agreement with the classical results. Some plots of the normalized magnetic or electric field are given for the three cases. An approximate method for studying the imperfectly conducting boss and ground plane is suggested.