The effects of point defects on transmission coefficients in two-dimensional piezoelectric phononic crystals

Based on finite-difference time-domain （FDTD） method, the wave propagation and localization in two-dimensional defect-containing piezoelectric phononic crystals are investigated when the mechanical-electrical coupling is taken into account. The characteristics of localized defect modes are studied, and the effects of the number and direction of defects on the defect modes and transmission coefficients are discussed. Numerical results of defect modes and transmission coefficients are presented for BaTiO3/polymer piezocomposite, and from which we can see that the number and direction of defects have pronounced effects on the defect modes and transmission coefficients. The results also show the existence of elastic wave localization in piezoelectric phononic crystals containing defects.