Transient Analysis of Conducting Half-Plane Problem with Noncausal Scattering Image

摘要

Two-dimensional transient scattering from a perfectly conducting half plane is studied. The excitation is an infinite impulsive line current parallel to edge of the conductor. Due to the symmetry of the problem, the electromagnetic field everywhere is TM along the direction defined by the edge. The analysis presented in the paper is based on new time-harmonic image solution found for the scattered field. The frequency-domain image current giving the reflected and diffracted fields is an exact function that can be expressed in terms of simple trigonometric functions. It is dependent only on the coordinates and the amplitude of the source, but interestingly, it is independent of frequency. Thus, the corresponding time-domain image is independent of time, which makes it noncausal. However, when integrating this image to compute the actual field, physical and causal results are obtained.