Network theoretic analysis of transducers

Abstract

Starting with the open-circuit or short-circuit electroelastic normal modes of a piezoelectric body, one can compute an equivalent electromechanical admittance matrix or hydrid parameter matrix. This matrix effectively transforms the piezoelectric body into an N-port network. One is thus able to bring to bear upon transducer problems the well-developed theory of N-port networks. We have done this for a radially polarized and tangentially polarized (segmented) ferroelectric shell. In particular, we have computed the open-circuit voltage response of the radially polarized shell (assuming it to be in a hydrophone) by utilizing the admittance matrix approach, which is based on the short-circuit normal modes, and the hybrid parameter approach, which is based on the open-circuit normal modes. A comparison of the two approaches is made. In addition, we describe an application of the theory to determining the driving-point (electrical) impedance of a projector consisting of a coaxial array of segmented shells. This is done by treating both the array of shells and the surrounding fluid medium as coupled N-port networks.