Broad band single crystal transducer for contrast agent harmonic imaging

• Published in: IEEE Ultrasonics Symposium, 2004 Vol. 2; pp. 1030 - 1033 Vol.2
• Main Authors: Hackenberger, W., Xiaoning Jiang, Rehrig, P.W., Xuecang Geng, Winder, A., Forsberg, F.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2004
• Subjects: Bandwidth; Crystals; Educational institutions; Frequency; Impedance; Piezoelectric transducers; Resonance; Testing; Ultrasonic imaging; Ultrasonic transducers
• ISBN: 9780780384125; 0780384121
• ISSN: 1051-0117
• DOI: 10.1109/ULTSYM.2004.1417946

A broadband single element transducer was constructed from single crystal PMN-PT and tested to determine the feasibility of using this material for simultaneous sub-harmonic and second harmonic imaging. The transducer consisted of a 1-3 PMN-PT/epoxy composite with two quarter wave matching layers and a backing. The transducer face was spherically curved to yield a 53 mm focal point. The transducer's impulse response had a center frequency of 5.2 MHz and -6 dB bandwidth over 130%. The transmit response for tone burst excitation indicated a shift in center frequency to 6.5 MHz and a 6 dB bandwidth of 100%. Receive sensitivity was high at the lower end of the band and decreased with increasing frequency; this behavior was probably due to electrical impedance mismatch. Contrast agent testing using Sonazoid/spl reg/ showed that the second harmonic could be easily detected. The sub-harmonic was not detected due to the center frequency shift under tone burst excitation. Simultaneous sub, and second harmonic testing could probably be accomplished with a lower center frequency and better electrical impedance matching.