Treatment of boundary conditions in the analysis of PBG structures

Floquet theory is used in the analysis of periodic structures such as photonic crystals. We argue in this paper, that we can use the first form of the Floquet transform to treat the boundary conditions. The advantage is that we can use standard (nonperiodic) software for the analysis by the finite-element method. We give an example of this technique to the electromagnetic Kronig-Penny model in three space dimensions, where the use of vector elements is essential