1–3 Piezocomposites Based on Super-Cell Structuring for Transducer Applications

Abstract

In ultrasound transducers, the most popular fabrication method for 1–3 piezocomposites is the « dice and fill » method where lateral periodicity p is introduced and leads to the occurrence of lateral modes. These spurious modes can drastically damage the performance of the device if they appear near its thickness (h) mode, thus limiting the operational frequency range. In order to overcome the previous limitations while maintaining a good electromechanical efficiency for the 1–3 piezocomposites, a new fabrication method based on lamination is proposed. The piezocomposite is partially regular with a supercell structure composed of five piezoelectric rods and two different pitches in one direction. The chosen cell shape allows numerical modeling to be performed (ATILA software). This study is made in the frequency range 0.4–1.3 MHz. Experimental results (electroacoustic responses in water) confirm those obtained with the numerical simulations, showing that the super-cell composite can be used in a larger range of frequencies than regular composites, while keeping similar sensitivity and bandwidth.