title: Three-dimensional modelling of micromachined-ultrasonic-transducer arrays operating in water.
abstract: We report on the 3-D modelling of periodic arrays of capacitive micromachined ultrasonic transducers (cMUTs) operating in fluid. Specific developments have been performed to model biperiodic transducer arrays and to take into account radiation into any stratified media at the front-side as well as the back-side of the device. The model is based on a periodic finite-element-analysis/boundary-element-method (FEA/BEM). It is applied to micromachined ultrasonic transducers (MUTs), based on silicon-nitride-circular-membrane arrays on a silicon substrate, and operating in water. The spectrum characteristics of MUTs excited in phase are investigated, showing that very-large-band emission is achievable as previously demonstrated by many authors. However, other contributions are also found, depending on the excitation conditions, that do not radiate in the fluid. These contributions are identified as guided modes that could generate significant cross-talk effects. The origin and the nature of these modes is analyzed to gain insight in the actual operation of MUTs.
authors.affiliation: Département LPMO, Institut FEMTO-ST, CNRS UMR 6174, 32 avenue de l'Observatoire, 25044 Besançon Cedex, France. mikael.wilm@lpmo.edu
authors.forename: Mikaël
authors.initials: M
authors.lastname: Wilm
authors.forename: Alexandre
authors.initials: A
authors.lastname: Reinhardt
authors.forename: Vincent
authors.initials: V
authors.lastname: Laude
authors.forename: Raphaël
authors.initials: R
authors.lastname: Armati
authors.forename: William
authors.initials: W
authors.lastname: Daniau
authors.forename: Sylvain
authors.initials: S
authors.lastname: Ballandras
mesh_terms: D004867:Equipment Design; D020342:Finite Element Analysis; D006801:Humans; D008904:Miniaturization; D010507:Periodicity; D012825:Silicon / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation*; D014867:Water
chemical_list: D017655:Silicon Compounds; D014867:Water; C032734:silicon nitride; D012825:Silicon