Novel Compact Antennas for Biomedical Implants and Wireless Applications

dc.contributor.advisorDr. Robert J. Trew, Committee Memberen_US
dc.contributor.advisorDr. Zhilin Li, Committee Memberen_US
dc.contributor.advisorDr. Gianluca Lazzi, Committee Chairen_US
dc.contributor.advisorDr. Brian Hughes, Committee Memberen_US
dc.contributor.authorGosalia, Keyoor Chetanen_US
dc.date.accessioned2010-04-02T18:55:12Z
dc.date.available2010-04-02T18:55:12Z
dc.date.issued2005-08-09en_US
dc.degree.disciplineElectrical Engineeringen_US
dc.degree.leveldissertationen_US
dc.degree.namePhDen_US
dc.description.abstractNovel design methodologies and implementation techniques for antennas with an extremely small form factor (kr < 1; k is the wavenumber and r is the radius of enclosing spherical volume) are presented. These size reduction techniques are applied to design antennas for two emerging fields: Short (or long) range wireless connectivity and human body implants (prosthetic devices). The first test bed describes compact microstrip patch antennas employing polarization diversity for optimizing the available channel bandwidth in conventional wireless communications. Extremely small antennas (for implantation in an eye ball) operating at microwave frequencies for a visual prosthesis are designed and implemented for the second test bed. The visual prosthesis under consideration is an implantable prosthetic device which attempts to restore partial vision in the blind (patients suffering from retinal degeneration) by artificial stimulation of the retinal cells. Mutually exclusive power and data transfer via a wireless link with the implanted device is proposed where inductive coil coupling transfers power at low frequencies while data communication is performed using extraocular and intraocular antennas at microwave frequencies. The microwave data telemetry link is characterized computationally (using Finite Difference Time Domain-FDTD) and experimentally with appropriately sized external and implanted antennas. It is observed that the head and eye tissues act as a form of dielectric lens and improve the coupling performance between the two antennas (with intraocular antenna embedded in the eye ball) as compared to coupling in free space. The data telemetry link is characterized with novel small microstrip patch and planar wire dipole as intraocular antennas. An electromagnetic and thermal analysis of the operation of such a visual prosthesis is performed. Electromagnetic power deposition in the head is evaluated in terms of Specific Absorption Rate (SAR). Temperature rise in the tissues is characterized by computationally discretizing and implementing the bio-heat equation in three dimensions in an anatomically accurate head model.en_US
dc.identifier.otheretd-08092004-121935en_US
dc.identifier.urihttp://www.lib.ncsu.edu/resolver/1840.16/4508
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectplanar meander line dipoleen_US
dc.subjectsmall antennaen_US
dc.subjectcompact antennasen_US
dc.subjectbio-heat equationen_US
dc.subjectretinal prosthesisen_US
dc.subjectthermal elevationen_US
dc.subjectSARen_US
dc.subjecthuman body implanten_US
dc.titleNovel Compact Antennas for Biomedical Implants and Wireless Applicationsen_US

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