Multiple Diffraction of Edge Waves: Grazing Incidence and Slope Diffraction

This chapter investigates two special cases. The first case is a grazing incidence of edge waves on acoustically hard planar plates. In the asymptotic theory, the incident wave is approximated by an equivalent plane wave. The second case that also needs special treatment occurs when the scattering edge is located in the zero of the incident wave. This is the case for slope diffraction. The chapter considers the important one to be the slope diffraction of the first order, when the first derivative of the incident wave is not equal to zero. Such a situation occurs, for example, in reflector antennas, when one tries to decrease side lobes, and in the process of multiple diffraction between several scatterers or between different parts of the same scatterer. The chapter founds ray asymptotics using the stationary-phase technique.