Tunability of Bragg band gaps in one-dimensional piezoelectric phononic crystals using external capacitances

A one-dimensional stack of identical piezoelectric rods is investigated. The device exhibits a band gap related to electrical boundary condition. A separate control of the central frequency and of the width of the band gap is performed by an electrical boundary condition involving two different variable capacitances. Because the capacitances are grounded, a specific model has been developed and validated. Finally, experiments unambiguously confirmed previous theoretical observations.