Phase characteristics of thick metal gratings

Average Transition Conditions for Electromagnetic Fields at a Metascreen of Nonzero Thickness

“…The same behavior will occur in the TM polarization if X s TM = −X a TM /4, but the presence of k x = k 0 sin θ in (36) means that it can happen only for a single angle of incidence given fixed aperture size and screen thickness. A similar phenomenon has been previously observed for a grating of parallel wires [25], [26], and is explained by the compensation of the phase shift due to the thickness of the metascreen with that of the distortion of the local fields in the neighborhood of the apertures.…”

“…For the TE field, let E y → V and H x → −I. Inserting these into (26) and (27), we find that the metascreen can be represented by the equivalent circuit of Figure 3 placed at z = 0, wherein…”