A new equivalent circuit for piezoelectrics with three losses and external loads

High power density is an important target to achieve in the piezoelectric devices and it is primarily limited by internal losses in a piezoelectric material. There are three losses in piezoelectric materials: dielectric, elastic and piezoelectric losses. In this paper, a new equivalent circuit is proposed considering these three losses. First, a six-terminal equivalent circuit is derived based on the Mason's equivalent circuit. In order to verify the feasibility of the new circuit, four different external loads configurations which reflect intensive and extensive loss behaviors are explored and simulated. The resonance and antiresonance frequencies and their corresponding mechanical quality factors derived from the circuits are compared with the actual samples with the different loads and boundary conditions. The simulation results have the same trend as the experimental measurements. Equivalent circuits with only dielectric, elastic losses were simulated to verify the accuracy improvement of the new equivalent circuits. The voltage distribution of non-electrode sample is simulated with the proposed equivalent circuit and matches the experimental result on the actual sample.