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dc.contributor.authorQureshi, Muhammad Shakeelen_US
dc.date.accessioned2009-08-26T17:30:56Z
dc.date.available2009-08-26T17:30:56Z
dc.date.issued2009-06-03en_US
dc.identifier.urihttp://hdl.handle.net/1853/29613
dc.description.abstractThe 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.publisherGeorgia Institute of Technologyen_US
dc.subjectCMUTen_US
dc.subjectAnalogen_US
dc.subjectSigma Deltaen_US
dc.subjectSensorsen_US
dc.subjectOptical grating microphoneen_US
dc.subjectChopper amplifieren_US
dc.subjectUltrasounden_US
dc.subjectMEMSen_US
dc.subjectCircuitsen_US
dc.subjectCMOSen_US
dc.subjectAM demodulatorsen_US
dc.subjectLow voltageen_US
dc.subjectLow poweren_US
dc.subjectWide linear range amplfieren_US
dc.subjectWeak inversionen_US
dc.subjectTobi elementen_US
dc.subjectMixed signalen_US
dc.subject.lcshMicroelectromechanical systems
dc.subject.lcshDetectors
dc.subject.lcshDiagnostic ultrasonic imaging Image quality
dc.subject.lcshHearing aids
dc.subject.lcshMicrophone
dc.titleIntegrated front-end analog circuits for mems sensors in ultrasound imaging and optical grating based microphoneen_US
dc.typeDissertationen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentElectrical and Computer Engineeringen_US
dc.description.advisorCommittee Chair: Hasler, Paul; Committee Co-Chair: Degertekin, Levent; Committee Member: Anderson, David; Committee Member: Ayazi, Farrokh; Committee Member: Brand, Oliver; Committee Member: Hesketh, Peteren_US


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