Phased-Array Transducer for Intracardiac Echocardiography Based on 1–3 Piezocomposite

Abstract

In this study, an ultrasonic phased-array transducer was proposed, which could effectively improve the imaging performance by using 1–3 piezocomposite. The piezocomposite consists of PZT and epoxy, with a pitch of 70 μm, kerf of 20 μm, and thickness of 170 μm. The phased-array transducer has 64 elements; the size of each element is 85 μm × 1.3 mm; the pitch of the transducer is 100 μm; and the kerf between the elements is only 15 μm. To minimize the transducer size, the 1–3 composite uses an encase structure, which connects the upper surface of the composite directly to the flexible circuit board bonded to the lower surface as the ground electrode. The size of the final fabricated transducer is 2 mm × 7.4 mm, and the transducer is mounted on a 9 F (3 mm diameter) catheter, which can bend in four directions and is primarily used for intracardiac echocardiography (ICE). The acoustic and electrical properties of the transducer were tested, including impedance, echo sensitivity, center frequency (9 MHz), bandwidth (BW) (55%), and consistency. Finally, the wire phantom experiments were carried out to demonstrate the spatial resolutions and imaging performance. This study shows that this transducer with compact design and construction can bring higher performance for the single-use disposable ICE catheter.