On Scattering from Faceted Radomes

At any rate, the characterization of the surface waves on a finite FSS structure by their actual propagation constant appears not to have occurred until recently in papers by Munk et al. [87] and Tanning and Munk [88], as well as in the dissertation by Tanning [77] and the thesis by Pryor [76], 

It is instructive to speculate on the reasons for this scant attention. Some of them appear to be related to the following  

Instead of finite wire sections, infinite long wires (or narrow strips) were used that is, instead of a double periodic surface, only a single periodic one was nsed. These cannot support surface waves of the type discussed here (see Section 4.9.3). 

The frequency band investigated was not sufficiently below the resonance of the structure (20-30%). For further discussion see Section 4.9.3. 

The interelement spacings Dx were not less than X/2 that is, grating lobes could occur as we move into imaginary space. As discussed in Section 4.9.3, that automatically rules out free surface waves. 

---