Improving the operational bandwidth of a 1-3 piezoelectric composite transducer using Sierpinski Gasket fractal geometry

Wider operational bandwidth is an important requirement of an ultrasound transducer across many applications. It has been reported mathematically that by having elements with varying length scales in the piezoelectric transducer design, the device may possess a wider operational bandwidth or a higher sensitivity compared to a conventional device. In this paper, the potential for extending the operational bandwidth of a 1-3 piezoelectric composite transducer configured in a fractal geometry, known as the Sierpinski Gasket (SG), will be investigated using finite element analysis package PZFlex (Thornton Tomasetti). Two equivalent piezocomposite designs will be simulated: a conventional 1-3 piezocomposite structure and the novel SG fractal geometry arrangement. The transmit voltage response and open circuit voltage extracted from the simulations are used to illustrate the improved bandwidth predicted from the fractal composite design.