Unbiased charged circular CMUT microphone: lumped-element modeling and performance
Date
2018
Editor(s)
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Print ISSN
0885-3010
Electronic ISSN
1525-8955
Publisher
Institute of Electrical and Electronics Engineers
Volume
65
Issue
1
Pages
60 - 71
Language
English
Type
Journal Title
Journal ISSN
Volume Title
Series
Abstract
An energy-consistent lumped-element equivalent circuit model for charged circular capacitive micromachined ultrasonic transducer (CMUT) cell is derived and presented. It is analytically shown and experimentally verified that a series dc voltage source at the electrical terminals is sufficient to model the charging in CMUT. A model-based method for determining this potential from impedance measurements at low bias voltages is presented. The model is validated experimentally using an airborne CMUT, which resonates at 103 kHz. Impedance measurements, reception measurements at resonance and off-resonance, and the transient response of the CMUT are compared with the model predictions.