Significant contribution of nonphysical leaky mode to the field excited by a source

We were the first to report on printed-circuit transmission lines that nonphysical improper real solutions may have a significant effect on the physical total field excited by a source. We have recently studied such interesting and unexpected effects in more detail, and we have discovered here that a nonphysical leaky solution may also cause a significant effect on the physical near field excited by a source, contrary to earlier belief. This effect has been investigated from the viewpoint of the evolution of eigenvalue solutions, which are extracted from both the finite-difference time-domain numerical data and the measurement data through the generalized pencil of functions technique