Analytic Approximation of Free-Space Path Loss for Implanted Antennas

Fuente: arXiv
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Main Authors: Gao, Mingxiang, Raman, Sujith, Sipus, Zvonimir, Skrivervik, Anja K.
Format: Preprint
Published: 2023
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author Gao, Mingxiang
Raman, Sujith
Sipus, Zvonimir
Skrivervik, Anja K.
author_facet Gao, Mingxiang
Raman, Sujith
Sipus, Zvonimir
Skrivervik, Anja K.
contents Implantable wireless bioelectronic devices enable communication and/or power transfer through RF wireless connections with external nodes. These devices encounter notable design challenges due to the lossy nature of the host body, which significantly diminishes the radiation efficiency of the implanted antenna and tightens the wireless link budget. Prior research has yielded closed-form approximate expressions for estimating losses occurring within the lossy host body, known as the in-body path loss. To assess the total path loss between the implanted transmitter and external receiver, this paper focuses on the free-space path loss of the implanted antenna, from the body-air interface to the external node. This is not trivial, as in addition to the inherent radial spreading of spherical electromagnetic waves common to all antennas, implanted antennas confront additional losses arising from electromagnetic scattering at the interface between the host body and air. Employing analytical modeling, we propose closed-form approximate expressions for estimating this free-space path loss. The approximation is formulated as a function of the free-space distance, the curvature radius of the body-air interface, the depth of the implanted antenna, and the permittivity of the lossy medium. This proposed method undergoes thorough validation through numerical calculations, simulations, and measurements for different implanted antenna scenarios. This study contributes to a comprehensive understanding of the path loss in implanted antennas and provides a reliable analytical framework for their efficient design and performance evaluation.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14731
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Analytic Approximation of Free-Space Path Loss for Implanted Antennas
Gao, Mingxiang
Raman, Sujith
Sipus, Zvonimir
Skrivervik, Anja K.
Medical Physics
Applied Physics
Implantable wireless bioelectronic devices enable communication and/or power transfer through RF wireless connections with external nodes. These devices encounter notable design challenges due to the lossy nature of the host body, which significantly diminishes the radiation efficiency of the implanted antenna and tightens the wireless link budget. Prior research has yielded closed-form approximate expressions for estimating losses occurring within the lossy host body, known as the in-body path loss. To assess the total path loss between the implanted transmitter and external receiver, this paper focuses on the free-space path loss of the implanted antenna, from the body-air interface to the external node. This is not trivial, as in addition to the inherent radial spreading of spherical electromagnetic waves common to all antennas, implanted antennas confront additional losses arising from electromagnetic scattering at the interface between the host body and air. Employing analytical modeling, we propose closed-form approximate expressions for estimating this free-space path loss. The approximation is formulated as a function of the free-space distance, the curvature radius of the body-air interface, the depth of the implanted antenna, and the permittivity of the lossy medium. This proposed method undergoes thorough validation through numerical calculations, simulations, and measurements for different implanted antenna scenarios. This study contributes to a comprehensive understanding of the path loss in implanted antennas and provides a reliable analytical framework for their efficient design and performance evaluation.
title Analytic Approximation of Free-Space Path Loss for Implanted Antennas
topic Medical Physics
Applied Physics
url https://arxiv.org/abs/2312.14731