TRANSIENT ANALYSIS OF CONDUCTING HALF-PLANE PROBLEM WITH NONCAUSAL SCATTERING IMAGE

In the present article two-dimensional transient scattering from a per fectly conducting halfplane is studied. The excitation is an infinite impulsive line current parallel to edge of the conductor. Due to the s ymmetry of the problem the electromagnetic field everywhere is TM alon g the direction defined by the edge. The analysis presented in this ar ticle is based on a new time-harmonic image solution found for the sca ttered field. The frequency-domain image current giving the reflected and diffracted fields is an exact function that can be expressed in te rms of simple trigonometric functions. It is dependent only on the coo rdinates and the amplitude of the source, but interestingly, it is ind ependent of the used frequency. Thus, the corresponding time-domain im age is independent of time, which makes it noncausal. However, when in tegrating this image to compute the actual field, physical and causal results are obtained. (C) 1994 John Wiley & Sons, Inc.