On the design of piezoelectric sensors and actuators

Abstract Piezoelectric devices are becoming more common with the introduction of smart sensors and actuators, and new developments in piezoelectric polymers and ceramics. However, as the authors found, obtaining relevant information for a comprehensive design of piezoelectric sensors and actuators is quite an ordeal. The literature on piezoelectricity is mainly divided on oversimplified explanations based on quartz crystals or on journals and books requiring an extensive background in solid state physics. This paper provides a non-trivial description of piezoelectricity from the perspective of sensor/actuator design. Contributions include: (a) using a simple matrix approach to (i) clearly describe the piezoelectric relationships, and (ii) clearly show how to manipulate the boundary conditions to experimentally obtain the constitutive parameters; (b) showing how the coefficients in the transfer function of a pressure sensor vary as the mode of operation change from isothermal to adiabatic by defining effective capacitances, permitivity, piezoelectric, and compliance constants; (c) showing that the wave equation is a natural result of introducing a kinetic energy term into the energy balance.