Comparisons of experimental data with theory for the diffracted fields behind a parallel planar array of dielectric cylinders indicate the importance of iterative focusing in explaining field anomalies.
L. Barkley, B. A. Howarth, and T. J. F. Pavlasek, "Iterative focusing in a parallel planar array of dielectric cylinders," J. Opt. Soc. Am. 63, 673-675 (1973)