Assessing the Intrinsic Radiation Efficiency of Tissue Implanted UHF Antennas

Research output: Contribution to journalArticle

Abstract

Dielectric loss occurring in tissues in close proximity to UHF implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency measures external to the tissue phantom employed. This approach means that radiation efficiency is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic radiation efficiency of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least λg/2 from the radiating structure. Simulated results are presented for canonical antennas at 403 MHz and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas nearfield dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.
LanguageEnglish
JournalIEEE Transactions on Antennas and Propagation
Early online date19 Aug 2019
DOIs
Publication statusEarly online date - 19 Aug 2019

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Tissue
Antennas
Radiation
Dielectric losses
Oils and fats
Muscle
Water content
Numerical analysis
Communication systems
Testing
Water

Keywords

  • Antenna efficiency
  • radiation efficiency
  • implantable antennas
  • reactive near-field
  • path loss
  • antenna characterization

Cite this

@article{60a648016c1a44e98b3a5b71008d5e30,
title = "Assessing the Intrinsic Radiation Efficiency of Tissue Implanted UHF Antennas",
abstract = "Dielectric loss occurring in tissues in close proximity to UHF implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency measures external to the tissue phantom employed. This approach means that radiation efficiency is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic radiation efficiency of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least λg/2 from the radiating structure. Simulated results are presented for canonical antennas at 403 MHz and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas nearfield dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.",
keywords = "Antenna efficiency, radiation efficiency, implantable antennas, reactive near-field, path loss, antenna characterization",
author = "Yomna El-Saboni and Dmitry Zelenchuk and Gareth Conway and William Scanlon",
year = "2019",
month = "8",
day = "19",
doi = "10.1109/tap.2019.2935113",
language = "English",
journal = "IEEE Transactions on Antennas and Propagation",
issn = "0018-926X",
publisher = "Institute of Electrical and Electronics Engineers Inc.",

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TY - JOUR

T1 - Assessing the Intrinsic Radiation Efficiency of Tissue Implanted UHF Antennas

AU - El-Saboni, Yomna

AU - Zelenchuk, Dmitry

AU - Conway, Gareth

AU - Scanlon, William

PY - 2019/8/19

Y1 - 2019/8/19

N2 - Dielectric loss occurring in tissues in close proximity to UHF implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency measures external to the tissue phantom employed. This approach means that radiation efficiency is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic radiation efficiency of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least λg/2 from the radiating structure. Simulated results are presented for canonical antennas at 403 MHz and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas nearfield dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.

AB - Dielectric loss occurring in tissues in close proximity to UHF implanted antennas is an important factor in the performance of medical implant communication systems. Common practice in numerical analysis and testing is to utilize radiation efficiency measures external to the tissue phantom employed. This approach means that radiation efficiency is also dependent on the phantom used and antenna positioning, making it difficult to understand antenna performance and minimize near-field tissue losses. Therefore, an alternative methodology for determining the intrinsic radiation performance of implanted antennas that focuses on assessing structural and near field tissue losses is presented. The new method is independent of the tissue phantom employed and can be used for quantitative comparison of designs across different studies. The intrinsic radiation efficiency of an implant antenna is determined by assessing the power flow within the tissue phantom at a distance of at least λg/2 from the radiating structure. Simulated results are presented for canonical antennas at 403 MHz and 2400 MHz in homogeneous muscle and fat phantoms. These illustrate the dominance of propagating path losses in high-water content tissues such as muscle, whereas nearfield dielectric losses may be more important in low-water tissues such as fat due to the extended reactive near-field.

KW - Antenna efficiency

KW - radiation efficiency

KW - implantable antennas

KW - reactive near-field

KW - path loss

KW - antenna characterization

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DO - 10.1109/tap.2019.2935113

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JF - IEEE Transactions on Antennas and Propagation

SN - 0018-926X

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