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Capacitive micromachined ultrasonic transducer arrays as tunable acoustic metamaterials

2014; American Institute of Physics; Volume: 104; Issue: 5 Linguagem: Inglês

10.1063/1.4864635

1520-8842

Shane Lani, M. Wasequr Rashid, Jennifer Hasler, Karim G. Sabra, F. Levent Degertekin,

Innovative Energy Harvesting Technologies

Capacitive Micromachined Ultrasonic Transducers (CMUTs) operating in immersion support dispersive evanescent waves due to the subwavelength periodic structure of electrostatically actuated membranes in the array. Evanescent wave characteristics also depend on the membrane resonance which is modified by the externally applied bias voltage, offering a mechanism to tune the CMUT array as an acoustic metamaterial. The dispersion and tunability characteristics are examined using a computationally efficient, mutual radiation impedance based approach to model a finite-size array and realistic parameters of variation. The simulations are verified, and tunability is demonstrated by experiments on a linear CMUT array operating in 2-12 MHz range.