Piezocomposite array transducers optimization by breaking periodicity

In this work decreasing of the influence of spurious lateral vibration modes over a piezocomposite transducer array performance reached by means of breaking the periodicity of the piezoelectric elements of the array is quantitatively evaluated. 1-3 and 2-2 connectivity samples fabricated for evaluation by using conventional dice-and-fill technique have their thickness mode frequency nearby 0.5 MHz. Pitch periodicity is broken by extracting a certain number of piezoelectric elements of the array. We measured the acoustoelectric response of the transducer. We evaluated the effects of breaking periodicity over the behavior of the radiated field as well as over the power consumption of the samples as a function of frequency. Frequency scanning is applied over the transducer frequency range and measurements are made by means of Schieleren acousto-optic measuring system. In order to understand the dynamics of vibration of these structures we study the radiating surface vibration modes. The energy transfer between constituent piezoelectric elements is determined using an acoustic spectroscopy measuring method. Experimental results are compared with that obtained evaluating models known from the literature as well as and with the results gained from the calculation on a simple coupled oscillators model developed for this application. Interpretation of these results is made starting from a simple local one dimension model which well approach the experimental results of the 2-2 case. A suitable model construction take possible the design of rod-extracting strategies which lead us to obtain the desired transducer performances in spite of the fact that simple and easy to do array structures are used. Conclusions obtained in this work allow the optimization of design and fabrication of piezocomposite arrays.