Targeted band gap creation using mixed sonic crystal arrays including resonators and rigid scatterers

Sonic crystals are periodic structures that have acoustic band gaps centred at frequencies depending on the lattice constant of the array and on the direction of the incident acoustic wave. To eliminate this dependence, this work presents designed mixed structures constructed with rigid scatterers and resonators embedded in air. Specifically, balloons filled with a blend of air and helium were used as resonators, showing experimental evidence about the resonant behavior of an array formed with these balloons. As a result, the authors obtain full band gaps in a predetermined range of frequencies desired. (c) 2007 American Institute of Physics.