A new detection method for capacitive micromachined ultrasonic transducers

Citation
As. Ergun et al., A new detection method for capacitive micromachined ultrasonic transducers, IEEE ULTRAS, 48(4), 2001, pp. 932-942
Citations number
25
Categorie Soggetti
Optics & Acoustics
Journal title
IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL
ISSN journal
08853010 → ACNP
Volume
48
Issue
4
Year of publication
2001
Pages
932 - 942
Database
ISI
SICI code
0885-3010(200107)48:4<932:ANDMFC>2.0.ZU;2-N
Abstract
Capacitive micromachined ultrasonic transducers (cMUT) have become an alter native to piezoelectric transducers in the past few years. They consist of many small circular membranes that are connected in parallel. In this work, we report; a new detection method for cMUTs. We model the membranes as cap acitors and the interconnections between the membranes as inductors. This k ind of LC net-work is called an artificial transmission line. The vibration s of the membranes modulate the electrical length of the transmission line, which is proportional to the frequency of the signal through it. By measur ing the electrical length of the artificial line at a high RF frequency (in the gigahertz range), the vibrations of the membranes can be detected in a very sensitive manner. Far the devices we measured, we calculated the mini mum detectable displacement to be in the order of 10(-5) Angstrom/root Hz w ith a possible improvement to 10(-7) Angstrom/root Hz.