Similarity of Properties of Metamaterial Slow-Wave Structures and Metallic Periodic Structures

A study of the evolution of wave dispersion in systems of all-metallic periodic structures with increasing corrugation depth shows a similarity of the properties of waves in metamaterial slow-wave structures (MSWSs) and traditional metallic SWSs used in high-power microwave sources. We show that the main properties of MSWSs, such as the existence of a lowest order negative dispersion wave below cutoff, also appear in ordinary metallic periodic systems with deep corrugations. Furthermore, we find that the appearance of negative dispersion in all-metallic periodic structures with increasing corrugation depth is accompanied by a hybrid mode being identified as the lowest order negative dispersion mode.