Radiation impedance study of a capacitive micromachined ultrasonic transducer by finite element analysis


BAYRAM B.

JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, vol.138, no.2, pp.614-623, 2015 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 138 Issue: 2
  • Publication Date: 2015
  • Doi Number: 10.1121/1.4923361
  • Title of Journal : JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
  • Page Numbers: pp.614-623

Abstract

In this study, radiation impedance of a capacitive micromachined ultrasonic transducer composed of square-shaped membranes arranged in m x m configuration (m = 1 - 5) is investigated using finite element analysis (FEA) of a commercially available software package (ANSYS). Radiation impedance is calculated for immersed membranes operating in conventional and collapse modes. Individual membrane response within the multi-membrane configuration is analyzed, and excited modes and their effects on radiation impedance and the pressure spectra are reported. This FEA provides an accurate behavior of the acoustic coupling of a thin membrane in a multi-membrane configuration, and extends above the anti-resonance frequency. The first resonance frequency of the membrane is excited for m x m (m >= 3) configuration in conventional mode and for m x m (m >= 2) configuration in collapse mode. Therefore, this frequency is determined to be responsible for the adverse effects observed in radiation impedance and pressure spectrum. A membrane configuration, which is missing the central membrane from the full m x m configuration is proposed, and is investigated with the FEA. This study is beneficial for the design of precise transducers suited for biomedical applications. (C) 2015 Acoustical Society of America.