Multiple matching scheme for broadband 0.72Pb(Mg[sub ⅓]Nb[sub ⅔])O₃−0.28PbTiO₃single crystal phased-array transducer

Abstract

Lead magnesium niobate–lead titanate single crystal 0.72Pb(Mg[sub ⅓]Nb[sub ⅔])O₃−0.28PbTiO₃(abbreviated as PMN-PT) was used to fabricate high performance ultrasonic phased-array transducer as it exhibited excellent piezoelectric properties. In this paper, we focus on the design and fabrication of a low-loss and wide-band transducer for medical imaging applications. A KLM model based simulation software PiezoCAD was used for acoustic design of the transducer including the front-face matching and backing. The calculated results show that the −6 dB transducer bandwidth can be improved significantly by using double λ/8 matching layers and hard backing. A 4.0 MHz PMN-PT transducer array (with 16 elements) was fabricated and tested in a pulse-echo arrangement. A −6 dB bandwidth of 110% and two-way insertion loss of −46.5 dB were achieved.