Pulsed beam diffraction by a perfectly conducting wedge: local scattering models

摘要

Develops local scattering models for a collimated wavepacket (pulsed beam, PB) impinging on a perfectly conducting wedge. They are derived from an exact solution that has been derived previously. Unlike the exact solution, the local solutions have explicit space-time forms which parameterize the problem in terms of tractable phenomena that may be extended to noncanonical configurations. This is done in the second half of the paper wherein the local models are extended to accommodate astigmatic wavepackets for which there is no exact solution. The local models developed have the format of the geometrical theory diffraction and of the uniform theory of diffraction (UTD), extended to accommodate PB fields: they are governed by transient diffraction functions (time-domain counterparts of the UTD diffraction coefficient) but also include structure functions that describe the space-time distribution of the scattered wavepacket. They explain, uniformly, the physics of the scattering phenomena as a function of the PB parameters: direction, distance from the edge, spatial collimation, and pulse length.