MEMS BASED MULTI-MODE MULTI-CHANNEL PIEZOELECTRIC SENSOR FOR FULLY IMPLANTABLE COCHLEAR IMPLANTS

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2022-9
Pirim, Feyza
This thesis presents a novel multi-mode, multi-channel piezoelectric sensor with broad bandwidth that is placed on the ossicles via an attachment system. The proposed sensor collects the vibration of the ossicles and mechanically filters the incoming sound. The finite element model of the middle ear is constructed as a starting point to examine the characteristics of the middle ear. The vibration characteristic of the ossicle chain is studied and the most suitable locations for the sensor placement are discussed. The attachment mechanism is designed. The finite element model of the middle ear and the attachment mechanism is verified with the cadaver experiments. Requirements and limitations of the sensor are presented. Thin film pulsed laser deposited PZT is selected as piezoelectric material. The proposed sensor design is composed of 4 multi-mode M-shape cantilevers together with 11 standard cantilevers. It has a volume of 4.6×4.2×0.5 mm3. Resonance frequencies of the cantilevers are tuned by using finite element methodology. The performance of the sensor is examined experimentally. It is observed that multi-mode, multi-channel sensor can fully perform at 0.1g for the interval of 300Hz and 6kHz. Acoustic performance characterization of the sensor is conducted by placing the sensor on the artificial tympanic membrane. Sensor gives peak-to-peak voltage readouts of 546.2mVpp, 252.6mVpp, and 69.7mVpp at 100dB, 90dB and 80dB respectively. An alternative multi-mode design P-shape is presented. A maximum of 120.5mVpp is recorded from the P-shape design at 0.1g. Its results are examined and compared with M-shape multi-mode design.

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Citation Formats
F. Pirim, “MEMS BASED MULTI-MODE MULTI-CHANNEL PIEZOELECTRIC SENSOR FOR FULLY IMPLANTABLE COCHLEAR IMPLANTS,” M.S. - Master of Science, Middle East Technical University, 2022.