MEMS based multi-channel piezoelectric acoustic transducer for fully implantable cochlear implants

Date

2020

Author

Yüksel, Muhammed Berat

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

426
views

0
downloads

This thesis presents multi-channel acoustic MEMS transducer that is able to work within the audible frequency range (250-5500 Hz) and mimic the operation of a cochlea by filtering incoming sound. This transducer is composed of eight thin film piezoelectric cantilever beams possessing different resonance frequencies. The transducer is well suited to be implanted in a middle ear cavity with an active volume of 5 x 5 x0.6 mm3 and 4.8 mg. Resonance frequencies and piezoelectric outputs of the beams are modeled by using Finite Element Method (FEM). Vibration experiments showed that the transducer was capable of generating up to 139.36 mVpp under 0.1 g excitation. Test results are consistent with FEM model on frequency (97%) and output voltage (89%) values. It was also tested with acoustical excitation in a test setup including artificial tympanic membrane and flexible connection equipment. In that case, it generated up to 50.7 mVpp under 100 dB Sound Pressure Level (SPL). Output voltages observed in acoustical and mechanical characterizations are the highest reported ones to the best of my knowledge. For the first time in the literature, acoustical transducer was excited with speech sound and recovered by using software. Spectrograms of recorded and recovered signals showed close patterns. Moreover, recovered sound was recognizable. Beside stand-alone tests, in-vivo and in-vitro tests have been conducted with stimulation circuits. This stimulation system can operate in 50 dB dynamic range. Finally, a new beam structure is proposed to improve hearing quality by expanding the covered bands as a future work.

Subject Keywords

Microelectromechanical systems., Keywords: Acoustic Transducer, MEMS, Fully Implantable Cochlear Implant, Thin Film Piezoelectric.

URI

http://etd.lib.metu.edu.tr/upload/12625570/index.pdf
https://hdl.handle.net/11511/45804

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Thin-Film PZT based Multi-Channel Acoustic MEMS Transducer for Cochlear Implant Applications Yüksel, Muhammed Berat; Külah, Haluk (2021-01-01) AuthorThis paper presents a multi-channel acoustic transducer that works within the audible frequency range (250-5500 Hz) and mimics the operation of the cochlea by filtering incoming sound. The transducer is composed of eight thin film piezoelectric cantilever beams with different resonance frequencies. The transducer is well suited to be implanted in middle ear cavity with an active volume of 5 mm × 5 mm × 0.62 mm and mass of 4.8 mg. Resonance frequencies and piezoelectric outputs of the bea...
Multi-channel thin film piezoelectric acoustic transducer for cochlear implant applications YÜKSEL, MUHAMMED BERAT; İlik, Bedirhan; Koyuncuoğlu, Aziz; Külah, Haluk (2019-10-27) This paper presents a multi-channel piezoelectric acoustic transducer that is working within the audible frequency band (250- 5500 Hz). The transducer consists of eight cantilevers with thin film PLD-PZT piezoelectric layers. The transducer is well suited to be implanted in middle ear cavity with an active volume of 5x5x0.6 mm(3) and mass of 4.8 mg excluding the test frame. Finite Element Method (FEM) is used for modelling cantilever resonance frequencies and piezoelectric outputs. This model and shaker-tab...
Frequency tunable microstrip patch antenna using RF MEMS technology Erdıl, Emre; Topallı, Kagan; Unlu, Mehmet; Aydın Çivi, Hatice Özlem; Akın, Tayfun (2007-04-01) A novel reconfigurable microstrip patch antenna is presented that is monolithically integrated with RF microelectromechanical systems (MEMS) capacitors for tuning the resonant frequency. Reconfigurability of the operating frequency of the microstrip patch antenna is achieved by loading it with a coplanar waveguide (CPW) stub on which variable MEMS capacitors are placed periodically. MEMS capacitors are implemented with surface micromachining technology, where a 1-mu m thick aluminum structural layer is plac...
Thin Film PZT Acoustic Sensor for Fully Implantable Cochlear Implants İlik, Bedirhan; Koyuncuoğlu, Aziz; Uluşan, Hasan; Chamanıan, Salar; Işık Akçakaya, Dilek; Şardan Sukas, Özlem; Külah, Haluk (2017-09-06) This paper presents design and fabrication of a MEMS-based thin film piezoelectric transducer to be placed on an eardrum for fully-implantable cochlear implant (FICI) applications. Resonating at a specific frequency within the hearing band, the transducer senses eardrum vibration and generates the required voltage output for the stimulating circuitry. Moreover, high sensitivity of the sensor, 391.9 mV/Pa @900 Hz, decreases the required power for neural stimulation. The transducer provides highest voltage ou...
A Pulse-Width Modulated Cochlear Implant Interface Electronics with 513 mu W Power Consumption Yigit, Halil Andac; Ulusan, Hasan; Yüksel, Muhammed Berat; Chamanian, Salar; Çiftci, Berkay; Koyuncuoglu, Aziz; Muhtarolu, Ali; Külah, Haluk (2019-01-01) The fully implantable cochlear implant (FICI) interface circuit proposed in this work senses sound harmonics from 8 different piezoelectric cantilever sensors, and generates pulse width modulated biphasic current outputs to stimulate the auditory neurons. Signals from the piezoelectric sensors are amplified, rectified, and sampled. The sampled voltage is held and converted to current by a novel logarithmic voltage-to-current converter. The current is then digitized with a current comparator to determine the...

Citation Formats

M. B. Yüksel, “MEMS based multi-channel piezoelectric acoustic transducer for fully implantable cochlear implants,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2020.