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 …