Comparison of bandgaps of mushroom-type EBG surface and corrugated and strip-type soft surfaces

Corrugated and strip-loaded soft surfaces are characterised in the same way the electromagnetic bandgap (EBG) surfaces are characterized, that is, in terms of the bandgaps in their dispersion diagrams. The strip-loaded surfaces are provided with metalised via holes, and both central and lateral locations of these are investigated. It is found that strip-loaded surfaces with vias have the same bandgaps as mushroom-type EBG surfaces of the same period. It is also found that the strip-loaded surface can be designed to have the bandgap appearing at lower frequency than the mushroom surface, by locating the vias at the edge rather than in the middle and by optimising the period of the vias along the strips