Acoustic wave device employing reflective elements for confining elastic energy

An acoustic wave device comprising:

• a piezoelectric material;
• metallic electrodes carried by the piezoelectric material such that a difference of potential between two adjacent electrodes generates elastic energy by piezoelectric effect, wherein a primary wave propagation of acoustic waves is along a primary wave propagation path generally perpendicular to the metallic electrodes;
• and
• a plurality of obstacles reflecting at least a portion of the acoustic waves, the plurality of obstacles positioned generally parallel to a surface of the piezoelectric material for confining the elastic energy along the primary wave propagation path, wherein obstacles within the plurality of obstacles are separated by a preselected periodicity, and wherein at least one direction of periodicity is parallel to the metallic electrodes.