Tuning of band gaps for a two-dimensional piezoelectric phononic crystal with a rectangular lattice

In this paper,the elastic wave propagation in atwo-dimensional piezoelectric phononic crystal is studiedby considering the mechanic-electric coupling.The gener-alized eigenvalue equation is obtained by the relation of themechanic and electric fields as well as the Bloch-Floquet the-orem.The band structures of both the in-plane and anti-planemodes are calculated for a rectangular lattice by the plane-wave expansion method.The effects of the lattice constantratio and the piezoelectricity with different filling fractionsare analyzed.The results show that the largest gap width isnot always obtained for a square lattice.In some situations,a rectangular lattice may generate larger gaps.The band gapcharacteristics are influenced obviously by the piezoelectric-ity with the larger lattice constant ratios and the filling frac-tions.