Reverberation reduction in capacitive micromachined ultrasonic transducers (CMUTs) by front-face reflectivity minimization
| Autor: | Monica La Mura, Giosue Caliano, Barbara Mauti, Nicola Lamberti, Alessandro Stuart Savoia |
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| Přispěvatelé: | Dr. Nico F. Declercq, Savoia, ALESSANDRO STUART, La Mura, Monica, Mauti, Barbara, Lamberti, Nicola, Caliano, Giosue' |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Microelectromechanical systems
Materials science CMUT Transducer reflectivity Acoustics Reverberation Physics and Astronomy(all) Dissipation Capacitive Micromachined Ultrasonic Transducer (CMUT) MEMS Capacitive micromachined ultrasonic transducers Transducer Object-relational impedance mismatch Acoustic impedance Electrical impedance Microfabrication |
| Popis: | Front-face acoustic reflectivity of ultrasonic imaging transducers, due to acoustic impedance mismatch with the propagation medium, may cause reverberation phenomena during wideband pulse-echo operation. Front-face reflectivity may be reduced by promoting the transmission of the echoes, received from the medium, to the transducer backing, and by maximizing the mechanical-to-electrical energy conversion and dissipation by tuning the electrical load impedance connected to the transducer. In Capacitive Micromachined Ultrasonic Transducers (CMUTs), the energy transfer from the medium to the backing is very low due to the large impedance mismatch between the medium and the transducer substrate, typically made of silicon. Reverse Fabrication Process (RFP) makes it possible providing CMUTs with custom substrate materials, thus eliminating the original silicon microfabrication support. In this paper, we propose two methods for the front-face reflectivity reduction in RFP-CMUTs: the first one is based on the use of low-impedance, highly attenuating backing materials, and the second one is based on the maximization of the mechanoelectrical energy conversion and dissipation. We analyze the methods by finite element simulations and experimentally validate the obtained results by fabricating and characterizing single-element RFP-CMUTs provided with different backing materials and electrical loads. |
| Databáze: | OpenAIRE |
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