ACOUSTIC CHARACTERIZATION OF A MINIATURE MATRIX TRANSDUCER FOR PEDIATRIC 3D TRANSESOPHAGEAL ECHOCARDIOGRAPHY

This paper presents the design, fabrication and characterization of a miniature PZT-on-CMOS matrix transducer for real-time pediatric 3-dimensional (3D) transesophageal echocardiography (TEE). This 3D TEE probe consists of a 32 x 32 array of PZT elements integrated on top of an Application Specific Integrated Circuit (ASIC). We propose a partitioned transmit/receive array architecture wherein the 8 x 8 transmitter elements, located at the centre of the array, are directly wired out and the remaining receive elements are grouped into 96 sub-arrays of 3 x 3 elements. The echoes received by these sub-groups are locally processed by micro-beamformer circuits in the ASIC that allow pre-steering up to +/- 37 degrees. The PZT-on-CMOS matrix transducer has been characterized acoustically and has a centre frequency of 5.8 MHz, -6 dB bandwidth of 67%, a transmit efficiency of 6 kPa/V at 30 mm, and a receive dynamic range of 85 dB with minimum and maximum detectable pressures of 5 Pa and 84 kPa respectively. The properties are very suitable for a miniature pediatric real-time 3D TEE probe. (C) 2018 World Federation for Ultrasound in Medicine & Biology. All rights reserved.