Implantable ferrite antenna for biomedical applications

dc.contributorHong, Yang-Ki
dc.contributorHu, Fei
dc.contributorLemmon, Andrew N.
dc.contributorMankey, Gary J.
dc.contributor.advisorHong, Yang-Ki
dc.contributor.authorFazeli, Maxwell
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractWe have developed an implantable microstrip patch antenna with dimensions of 10×10×1.28 mm, operating around the Industrial, Scientific and Medical (ISM) band (2.4 – 2.5 GHz). The antenna is characterized in skin-mimicking gels and compared with simulation results. The experimental measurements are in good agreement with simulations, having a -16 dB reflection coefficient and -18 dBi realized gain at resonance, with a 185 MHz -10 dB bandwidth. The simulated effects of ferrite film loading on antenna performance are investigated, with comparisons made for 5 and 10 µm thick films, as well as for 10 µm thick films with varying magnetic loss (tan δµ = 0.05, 0.1 and 0.3). Our simulations reveal that the addition of 10 µm thick magnetic layers has effectively lowered the resonant frequency by 70 MHz, while improving return loss and -10 dB bandwidth by 3 dB and 40 MHz, respectively, over the uncoated antenna. Ferrite film coating also improved realized gain within the ISM band, with largest gain increases at resonance found for films having lower magnetic loss. Additionally, the gain (G) variance at ISM band limits, ΔGf(2.5GHz)-f(2.4GHz), decreased from 1.97 to 0.44 dBi for the antenna with 10 µm films over the non-ferrite antenna. The measured dip-coated NiCo ferrite films effectively reduces the antenna resonance by 110 MHz, with a 4.2 dB reflection coefficient improvement as compared to an antenna without ferrite. The measured ferrite antenna also reveals a 6 dBi and 35 MHz improvement in realized gain and -10 dB bandwidth, respectively, at resonance. Additionally, the ferrite-coated antenna shows improved directivity, with wave propagation attenuated at the direction facing the body internal. These results indicate that implantable antenna miniaturization and reliable wireless communication in the operating frequency band can be realized with ferrite loading.en_US
dc.format.extent70 p.
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectElectrical engineering
dc.subjectBiomedical engineering
dc.titleImplantable ferrite antenna for biomedical applicationsen_US
dc.typetext of Alabama. Department of Electrical and Computer Engineering and Computer Engineering University of Alabama's
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