Abstract
We have developed the periodic FMM in Helmholtz' equation in 2D. Indeed periodic boundary problems are deemed to be more and more important in engineering. In particular, photonic cristals, which have periodic structures, attract a great deal of interest as new types of optic devices in the field of electronics. As the first step of development of the solver of models of such periodic devices, we focus on scattering problems with cracks in 2D in this reserch. Through numerical analyses, the stop-band phenomenon is observed, which is the typical of photonic cristals.
