Title:
Integrated front-end analog circuits for mems sensors in ultrasound imaging and optical grating based microphone

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dc.contributor.advisor Hasler, Jennifer
dc.contributor.advisor Degertekin, F. Levent
dc.contributor.author Qureshi, Muhammad Shakeel en_US
dc.contributor.committeeMember Anderson, David
dc.contributor.committeeMember Ayazi, Farrokh
dc.contributor.committeeMember Brand, Oliver
dc.contributor.committeeMember Hesketh, Peter
dc.contributor.department Electrical and Computer Engineering en_US
dc.date.accessioned 2009-08-26T17:30:56Z
dc.date.available 2009-08-26T17:30:56Z
dc.date.issued 2009-06-03 en_US
dc.description.abstract The objective of this research is to develop and design front-end analog circuits for Capacitive Micromachined Ultrasound Transducers (CMUTs) and optical grating MEMS microphone. This work is motivated by the fact that with micro-scaling, MEMS sense capacitance gets smaller in a CMUT array element for intravascular ultrasound imaging, which has dimensions of 70um x 70um and sub pico-farad capacitance. Smaller sensors lead to a lower active-to-parasitic ratio and thus, degrads sensitivity. Area and power requirements are also very stringent, such as the case of intravascular catheter implementations with CMOS-First CMUT fabrication approach. In this implementation, capacitive feedback charge amplifier is an alternative approach to resistive feedback amplifiers. Capacitive feedback charge amplifier provides high sensitivity, small area, low distortion and saving power. This approach of charge amplifiers is also suitable in capacitive microphones where it provides low power and high sensitivity. Another approach to overcome capacitive detection challenges is to implement optical detection. In the case of biomimetic microphone structure, optical detection overcomes capacitive detection's thermal noise issues. Also with micro-scaling, optical detection overcomes the increased parasitics without any sensitivity degradation, unlike capacitive detection. For hearing aids, along with sensitivity, battery life is another challenge. We propose the use of 1-bit front-end sigma-delta ADC for overall improved hearing aid power efficiency. Front-end interface based on envelope detection and synchronous detection schemes have also been designed. These interface circuits consume currents in microampere range from a 1.5V battery. Circuit techniques are used for maximizing linear range and signal handling with low supplies. The entire front end signal processing with Vertical Cavity Surface Emitting Laser (VCSEL) drivers, photodiodes, filters and detectors is implemented on a single chip in 0.35um CMOS process. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/29613
dc.publisher Georgia Institute of Technology en_US
dc.subject CMUT en_US
dc.subject Analog en_US
dc.subject Sigma Delta en_US
dc.subject Sensors en_US
dc.subject Optical grating microphone en_US
dc.subject Chopper amplifier en_US
dc.subject Ultrasound en_US
dc.subject MEMS en_US
dc.subject Circuits en_US
dc.subject CMOS en_US
dc.subject AM demodulators en_US
dc.subject Low voltage en_US
dc.subject Low power en_US
dc.subject Wide linear range amplfier en_US
dc.subject Weak inversion en_US
dc.subject Tobi element en_US
dc.subject Mixed signal en_US
dc.subject.lcsh Microelectromechanical systems
dc.subject.lcsh Detectors
dc.subject.lcsh Diagnostic ultrasonic imaging Image quality
dc.subject.lcsh Hearing aids
dc.subject.lcsh Microphone
dc.title Integrated front-end analog circuits for mems sensors in ultrasound imaging and optical grating based microphone en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Degertekin, F. Levent
local.contributor.advisor Hasler, Jennifer
local.contributor.corporatename School of Electrical and Computer Engineering
local.contributor.corporatename College of Engineering
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