title: FEA modeling of CMUT with membrane stand-off structures to enable selectable frequency-mode operation.
abstract: A selectable, dual-frequency, capacitive micro- machined ultrasonic transducer (CMUT) designed for both high-frequency imaging and low-frequency therapeutic effect is presented. A validated finite element analysis (FEA) CMUT model was used to examine the performance of the proposed dual-frequency transducer. CMUT device simulations were used to design a hybrid device incorporating stand-off structures that divide a large, low-frequency membrane into smaller, high-frequency sub-membranes when the membrane is partially collapsed so that the stand-offs contact the substrate. In low-frequency operation, simulations indicated that the peak negative pressure achieved by the hybrid device, when biased by 30.0 VDC and excited by a 2-MHz signal with 30.0 V amplitude, exceeded 190 kPa, which is sufficient for microbubble rupture. Low-frequency mode bandwidth was 93% at a center frequency of 2.1 MHz. In the high-frequency mode of operation, the device was excited by 175 Vdc and 87.5 Vac, which generated a peak negative pressure of 247 kPa. Device center frequency was 44.1 MHz with a - 6-dB fractional bandwidth of 42%.
authors: Matthew D C
authors: MD
authors: Eames
authors: Theodore J
authors: TJ
authors: Reck
authors: Joseph P
authors: JP
authors: Kilroy
authors: John A
authors: JA
authors: Hossack
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D025802:Electric Capacitance; D004867:Equipment Design; D019544:Equipment Failure Analysis; D020342:Finite Element Analysis; D008567:Membranes, Artificial; D008962:Models, Theoretical; D014159:Transducers; D014464:Ultrasonic Therapy / Q000295:instrumentation*
chemical_list: D008567:Membranes, Artificial