Q. Ke, W. H. Liew, L. Zhang, C. K. I. Tan, C. Jiang and K. Yao, "Broadband Ultrasonic Array Transducer From Multilayer Piezoelectric Ceramic With Lowered Co-Firing Temperature," in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 67, no. 5, pp. 968-974, May 2020, doi: 10.1109/TUFFC.2019.2959038.
Abstract:
Increasing array transducer bandwidth and signal-to-nose ratio (SNR) is a critical issue for producing high-quality medical ultrasound image. However, array elements with small size tend to have a poor sensitivity due to a much higher impedance compared to the electrical impedance of transmit and receive circuit. Implementation of multilayer ceramic (MLC) is an effective way for reducing impedance, thus with potential for improving SNR for ultrasonic probe. In this work, we fabricated multilayer piezoelectric ceramic with a composition of 0.1Pb(Ni1/3Nb2/3)O3-0.35Pb(Zn1/3Nb2/3)O3-0.15Pb(Mg1/3Nb2/3)O3-0.1PbZrO3-0.3PbTiO3-4mol% excess NiO (PNN-PZN-PMN-PZ-PT), by a roll to roll tape casting process and co-fired with 90Ag/10Pd electrode at low temperature of 950 °C. Using 5-layer MLC (5L-MLC) as obtained, we designed and demonstrated a 5 MHz 32-element array transducer for ultrasonic and photoacoustic imaging. The 5-layer transducer element exhibited a bandwidth of 87% at -6 dB, substantially higher than 62% for single layer ceramic (SLC) element. In addition, the insertion loss was improved by 16.2 dB over the SLC element with external impedance of 50 Ω. Both the experimental results and theoretical analysis showed that our array transducer made of the PNN-PZN-PMN-PZ-PT multilayer ceramic is promising for acquiring high quality ultrasonic and photoacoustic images.
License type:
PublisherCopyrights
Funding Info:
This project is supported by National Research Foundation Competitive Research Programme of Singapore, NRF-CRP15-2015-04, (IMRE/16-9P1122).