Frequency-Interleaved MEMS Ultrasound Transducer

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This paper presents an ultra-sensitive, broad-bandwidth ultrasound transducer based on frequency interleaving of resonant transducers. A large number of cantilever-like diaphragm transducers with piezoelectric ZnO films have been optimally connected in series and parallel, so that the sensitivity as a receiver and the sound output as a transmitter are measured to be about 30 times larger than those of a single transducer. The interleaving of the transducers not only increases the sensitivity but also broadens the useable bandwidth greatly. Each individual transducer’s sound pressure output was measured about 3 mm away from the transducer in an open field with a calibrated microphone. A single transducer was measured to produce 0.8Pa at 22kHz when it was driven with 75Vpeak-to-peak , while it was measured to have a receiving sensitivity of 100μV/Pa at 22kHz. When 16 such transducers were connected in parallel, both the sound output and the sensitivity were improved to 4Pa and 1.05mV/Pa, respectively. When 64 such transducers were connected in parallel, followed by 4 such sets in series, the sound output and the sensitivity were improved to 10Pa and 2.9mV/Pa, respectively. The useable bandwidth also was greatly improved.

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Journal: TechConnect Briefs
Volume: 2, Nanotechnology 2010: Electronics, Devices, Fabrication, MEMS, Fluidics and Computational
Published: June 21, 2010
Pages: 312 - 315
Industry sector: Sensors, MEMS, Electronics
Topic: MEMS & NEMS Devices, Modeling & Applications
ISBN: 978-1-4398-3402-2