Comments on "Radiation of an aperture antenna covered by a spherical-shell chiral radome and fed by a circular waveguide"

In a recent paper, Li et al. (see ibid., vol.46, p.664-71, May 1998) used image theory to ascertain the electromagnetic response of a bounded region-a hemispherical shell-filled with an isotropic chiral medium situated above a perfect electrically conducting (PEC) ground plane. Although no details are given on the manner in which image theory was applied, the constitutive properties of the actual medium and its image medium are taken in the above paper to coincide exactly. The present author points out that the formulation and the results provided are incorrect, having emerged from an incorrect application of image theory.