Effects of non-periodic variations in periodic RF structures
The theory of perfectly periodic RF structures has been extensively developed, motivated largely by the many applications, some of which are millimeter wave radiation sources, amplifiers, and slow-wave circuits. Of course, the realization of a periodic structure is never perfect, due to fabrication tolerances and variations in material properties from cell to cell. Such differences among cells may also be intentionally introduced in order to tailor the structure properties for a specific application. In the perfectly periodic case, the geometry and composition of a single cell determines the dispersive and other electromagnetic properties of the structure; these properties are also affected by the properties of the terminations, for structures of finite length.