Study of ultrasound transducer which produces second harmonic superimposed signal

Zulfadhli Zaini, Shin Ichiro Umemura, Hayato Jimbo, Ryo Takagi, Shin Yoshizawa

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Cavitation is the formation of gas cavities in a liquid, in the consequence of rarefactional pressure acting upon the liquid. Producing such negative pressure exceeding the cavitation threshold in a travelling wave mode is hard to achieve due to nonlinear propagation followed by focal phase shift. Superimposing the second harmonic to fundamental is an alternative way to solve the problem while able to efficiently form and control the cavitation bubbles which expedite the treatment with high intensity focused ultrasound (HIFU). However, an air-backed transducer in conventional design is not suitable to generate both the second harmonic and fundamental at the same time. In order to overcome this problem, we propose a high impedance matching layer approach. We further explore the possibility of a double matching layer design with an additional lighter layer, to increase the performance of the transducer. Numerical simulation and experimental measurement have shown that by using high impedance matching layer, efficiently generating both the second harmonic (2 MHz) and fundamental (1 MHz) at the same time is possible. Numerical simulation also showed that further study is needed for the double matching layer approach to significant improve the performance.

Original languageEnglish
Title of host publication2015 IEEE International Ultrasonics Symposium, IUS 2015
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781479981823
Publication statusPublished - 2015 Nov 13
EventIEEE International Ultrasonics Symposium, IUS 2015 - Taipei, Taiwan, Province of China
Duration: 2015 Oct 212015 Oct 24

Publication series

Name2015 IEEE International Ultrasonics Symposium, IUS 2015


ConferenceIEEE International Ultrasonics Symposium, IUS 2015
Country/TerritoryTaiwan, Province of China


  • cavitation bubbles
  • double matching layer
  • high impedance matching layer
  • high intensity focused ultrasound
  • piezocomposite


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