Dual-concentric LiNbO₃/P(VDF-TrFE) copolymer transducer for high-frequency ultrasound imaging

In this paper, a dual-concentric transducer made of LiNbO₃ (lithium niobate) and P(VDF-TrFE) (poly(vinylidene fluoride-trifluoroethylene)) copolymer for high-frequency ultrasound imaging is presented. Typically, LiNbO₃ is a good transmitter because it has a high-electromechanical-coupling coefficient. Meanwhile, the P(VDF-TrFE) copolymer has been frequently used as a receiver because it has a high voltage constant and a low acoustic impedance capable of providing a transducer with a broad bandwidth. In the proposed dual-concentric transducer, the ultrasound is transmitted by an outer-ring-type transducer made of LiNbO₃, and the reflected pulse echo signal is received by an inner-disk-type transducer made of the P(VDF-TrFE) copolymer. This study showed the feasibility of a dual-concentric LiNbO₃/P(VDF-TrFE) copolymer transducer capable of simultaneously achieving a high sensitivity and a broad bandwidth.