Frequency modulation in the transmittivity of wave guides elastic-wave band-gap materials

It is shown, for the first time, that the transmittivity of wave guides cre ated as rectilinear defects in periodic elastic band-gap materials oscillat es as a function of frequency. The results are obtained using the finite di fference time domain method for elastic waves propagating in two-dimensiona l inhomogeneous media. The oscillations of the transmittivity are due to th e richness of modes in the elastic systems and, mainly, due to the periodic ity of the potential in the direction of the wave propagation. Results are presented for a periodic array of Ph and Ag cylinders inserted in an epoxy host, as well as for Hg cylinders in an Al host.