title: A finite difference model for cMUT devices.
abstract: A finite difference method was implemented to simulate capacitive micromachined ultrasonic transducers (cMUTs) and compared to models described in the literature such as finite element methods. Similar results were obtained. It was found that one master curve described the clamped capacitance. We introduced normalized capacitance versus normalized bias voltage and metallization rate, independent of layer thickness, gap height, and size membrane, leading to the determination of a coupling factor master curve. We present here calculations and measurements of electrical impedance for cMUTs. An electromechanical equivalent circuit was used to perform simulations. Our experimental measurements confirmed the theoretical results in terms of resonance, anti-resonance frequencies, clamped capacitance, and electromechanical coupling factor. Due to inhomogeneity of the tested element array and strong parasitic capacitance between cells, the maximum coupling coefficient value achieved was 0.27. Good agreement with theory was obtained for all findings.
authors.affiliation: LUSSI FRE CNRS 2448/ GIP Ultrasons, 37032 Tours, France. certon@univ-tours.fr
authors.forename: Dominique
authors.initials: D
authors.lastname: Certon
authors.forename: Franck
authors.initials: F
authors.lastname: Teston
authors.forename: Frédéric
authors.initials: F
authors.lastname: Patat
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D025802:Electric Capacitance; D004582:Electronics, Medical; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D016014:Linear Models; D008567:Membranes, Artificial; D008904:Miniaturization; D014159:Transducers; D014463:Ultrasonography / Q000295:instrumentation* / Q000379:methods
chemical_list: D008567:Membranes, Artificial