Abstract
This thesis is divided into two distinct parts. Part I, consisting of chapters 1 to 3, deals with the determination of the far field when an E-polarised electromagnetic plane wave is incident on an imperfectly conducting rectangular cylinder. In chapter 1 the field is determined when an E-polarised plane wave is incident on an imperfectly conducting right-angle wedge. In chapter 2, the results of chapter 1 and Keller's method of geometrical diffraction are used to determine the far field when an E-polarised plane wave is incident on an imperfectly conducting rectangular cylinder. Chapter 3 deals with certain singular directions for which the results of chapter 2 are no longer valid. Part II, consisting of chapters 4 to 7, deals with the determination of the electromagnetic field when an electromagnetic wave is incident on a dielectric wedge. In chapter 4 a basic integral equation and an iteration scheme for its solution, subject to certain restrictions on the refractive index of the wedge, is derived for incidence by an E or H-polarised field on an arbitrary angle dielectric wedge. Chapter 5 determines the electromagnetic field when an E-polarised plane wave is incident on a right-angle dielectric wedge whose refractive index (= n) is such that 1 < |n| < √2. In chapter 6 the electromagnetic far field is determined, when an arbitrary angle dielectric wedge whose refractive index is such that n ≈ 1, is illuminated by an E-polarised plane wave. The method of approach is different to that used in chapters 4 and 5, uses Kontorovich-Lebedev transforms In chapter 7 the field near to the tip of an arbitrary angle dielectric wedge of arbitrary refractive index, when illuminated by a line source of E or H-polarisation, is determined.