Active control of a piezoelectric Phononic Crystal using electrical impedance

We consider a one dimensional Phononic Crystal (PC) based on a stack of plates including piezoelectric layers. The model takes into account electrical external circuit connected to the piezoelectric layers with the exception of the layer for which the impedance is evaluated. Only longitudinal waves propagation (thickness modes) through the PC is taken into account. Experimentally, a finite periodic structure based on a PMMA/Pz26 elementary stack is studied in the MHz frequency range. Different types of external electrical load are investigated. The electrical impedance of an active layer is affected by the electrical boundary conditions and is related to changes in the band structure of the acoustic transmission through the PC.