Various equivalent circuits for thickness mode piezoelectric transducers

The equivalent transmission line model originally proposed by Nukiyama [5] and applied to the thickness mode piezoelectric transducers by Kikuchi et al. [6] is reviewed and its characteristics are described. The model is compared with those proposed by Mason [4] and by Krimholz et al. [2]. The equivalent transmission line model developed by Kikuchi et al. [6] was derived from the fundamental piezoelectric equation and Newton's equation of motion via the Laplace transformation. A new equivalent circuit in a time domain was derived as well. By comparing the equivalent circuit in a time domain with the equivalent transmission line model [6], it was demonstrated that the equivalent transmission line model is a fundamental equivalent circuit that is effective both for analyses in a time domain and for conventional analyses in a frequency domain. It is also demonstrated that, when the simultaneity between electric and acoustic signals is neglected, the equivalent circuits [2, 4] can be derived from the equivalent transmission line model.