Simulation and analysis of the PMN-PT based phased array transducer with the high sound velocity matching layer

Abstract

The finite element modeling (FEM) simulation and comparison of electroacoustic properties of the PMN-PT based phased arrays with high sound velocity (HSV) and low sound velocity (LSV) matching layers were investigated. The simulated keff of HSV layer based phased arrays (2.7 MHz) is higher than that of LSV matching layer based phased arrays, which reveals that the higher energy conversion efficiency is obtained. The vibration modal analysis shows that the average value of displacement ratio Rdisp of HSV matching layer based arrays (2.7 MHz) is 0.850, which is larger than that of LSV layer based arrays, indicating that the transmission efficiency of longitudinal energy can be enhanced with HSV matching layer. The interaction of transverse vibration between the adjacent elements for HSV layer based arrays become much weaker, which reduce the acoustic energy loss and the interference of transverse wave. The simulation results of echo performance illustrate that the relative error of all data is controlled at 2%, which proves that the FEM simulation has excellent accuracy compare to the practical results. The measured -6 dB bandwidth of the HSV layer based arrays (2.7 MHz) is 7.28 % higher than that of the LSV layer based arrays while the relative sensitivity is almost the same. Besides, the simulated results of electroacoustic properties of phased arrays with different center frequencies demonstrate that the -6 dB bandwidth increased by an average of 7.03 % and the crosstalk level decreased by an average of 1.91 dB when using the HSV matching layer. The crosstalk and clutter wave caused by the transverse vibration can be reduced by applying the HSV matching layer and thus a shorter pulse-echo response and enhancement of the bandwidth of the arrays can be obtained.