Optimization, Design and Analysis of a MEMS Microphone with PVDF as a Structural Layer for Cochlear Implant Applications
The cochlear implants are the most advanced technology for hearing aid impairments. It consists of a microphone or sensor, speech processor, stimulator, and the electrodes. The speech processor in the implant uses the MEMS microphones to pick the signals
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S. R. Karbari et al.
MEMS acoustic sensor is validated, and thus, demonstrating it can be reliably used as a piezoelectric membrane in a MEMS process of a product. Keywords Analytical Model · COMSOL Multiphysics · MEMS microphone · Cochlear Implants
1 Introduction Microphones are mechanical, acoustic, electrical sensors, and transducers which convert the signals from acoustic form into electrical form. These types of sensors are utilized in various numbers of electronic applications. MEMS-based microphones are dominant in the market due to the reasons such as their compact dimensions and size, a very good SNR ratio, faster response, very good sensitivity, and their stability for longer durations. In the past decade, the MEMS microphones have acquired a significant market share in various consumer applications like hearing aids and mobile handsets. With the advent of newer technologies and consumer demand, the quality of audio recording is expected to be high along with microphones that have the ability to suppress maximum amount of noise. Hence, for this reason, MEMS microphones are extensively used. The microphone picks up the acoustic waves and forwards to the speech processor where the processor decomposes to eight overlapping sub-bands and transmitted to an electrode that is surgically implanted into the cochlea of a deaf person in such a way that they can stimulate the appropriate region in the cochlea for the frequency they are transmitting. Here the proposed model with piezoelectric layer of PVDF and PVDF + PZT increases the spatial frequency band with reduced footprint and mass less than 20 mg. The microphone picks up the acoustic waves and forwards to the speech processor where the processor decomposes to eight overlapping sub-bands and transmitted to an electrode that is surgically implanted into the cochlea of a deaf person in such a way that they can stimulate the appropriate region in the cochlea for the frequency they are transmitting. Here the proposed model with piezoelectric layer of PVDF and PVDF + PZT increases the spatial frequency band with reduced footprint and mass less than 20 mg. The detection method for the commercially available MEMS microphone is by varying the capacitance and measuring it for the input acoustic vibrations. The electrodes micromachined using silicon technology for a capacitive-based includes the design that facilitates the changes in acoustic vibration to specific variations in capacitance. Along with the packaging, the dedicated read-out with analog or digital output has dimensions of few millimeters. The typical specifications of a MEMS microphone used in cochlear implants are as in Table 1. Weigold et al. analog devices fabricated successfully a spherical moving membrane of polysilicon and SCS with perforations on the back plate to reduce the stress of an SOI wafers. A spring suspension diaphragm with suspensions at the corners proposed by analog devices leads to increase in the sensitivity of the device
Optimization, Design and Analysis of a MEMS Microphone
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