The University of Southampton
University of Southampton Institutional Repository

Separation-independent wearable 6.78 MHz near-field radiative wireless power transfer using electrically-small embroidered textile coils

Separation-independent wearable 6.78 MHz near-field radiative wireless power transfer using electrically-small embroidered textile coils
Separation-independent wearable 6.78 MHz near-field radiative wireless power transfer using electrically-small embroidered textile coils

Achieving a wireless power transfer (WPT) link insensitive to separation is a key challenge to achieving power autonomy through wireless-powering and wireless energy harvesting over a longer range. While coupled WPT has been widely used for near-field high-efficiency WPT applications, the efficiency of the WPT link is highly sensitive to separation and alignment, making it unsuitable for mobile systems with unknown or loose coupling such as wearables. On the other hand, while ultra-high frequency (UHF) and microwave uncoupled radiative WPT (0.3–3 GHz) enables meters-long separation between the transmitter and the receivers, the end-to-end efficiency of the WPT link is adversely limited by the propagation losses. This work proposes radiative WPT, in the 6.78 MHz license-free band, as a hybrid solution to separation-independent WPT, thus mitigating the losses associated with coil separation. Resonant electrically small antennas were fabricated using embroidered textile coils and tuned using L-matching networks, for wearable WPT. The antenna’s efficiency and near-fields have been evaluated numerically and experimentally. The proposed WPT link achieves a stable forward transmission of S 21 > −17 dB and S 21 > −28 dB, independent of coil separation on the XZ and XY planes respectively, in a 27 m 3 volume space. The presented approach demonstrates the highest WPT link efficiency at more than 1-m separation and promises higher end-to-end efficiency compared to UHF WPT.

Coils, E-textiles, Electrically small antennas, Internet of things, Wireless energy harvesting, Wireless power transfer
1996-1073
1-14
Wagih, Mahmoud
7e7b16ba-0c64-4f95-bd3c-99064055f693
Komolafe, Abiodun
5e79fbab-38be-4a64-94d5-867a94690932
Zaghari, Bahareh
a0537db6-0dce-49a2-8103-0f4599ab5f6a
Wagih, Mahmoud
7e7b16ba-0c64-4f95-bd3c-99064055f693
Komolafe, Abiodun
5e79fbab-38be-4a64-94d5-867a94690932
Zaghari, Bahareh
a0537db6-0dce-49a2-8103-0f4599ab5f6a

Wagih, Mahmoud, Komolafe, Abiodun and Zaghari, Bahareh (2020) Separation-independent wearable 6.78 MHz near-field radiative wireless power transfer using electrically-small embroidered textile coils. Energies, 13 (3), 1-14, [528]. (doi:10.3390/en13030528).

Record type: Article

Abstract

Achieving a wireless power transfer (WPT) link insensitive to separation is a key challenge to achieving power autonomy through wireless-powering and wireless energy harvesting over a longer range. While coupled WPT has been widely used for near-field high-efficiency WPT applications, the efficiency of the WPT link is highly sensitive to separation and alignment, making it unsuitable for mobile systems with unknown or loose coupling such as wearables. On the other hand, while ultra-high frequency (UHF) and microwave uncoupled radiative WPT (0.3–3 GHz) enables meters-long separation between the transmitter and the receivers, the end-to-end efficiency of the WPT link is adversely limited by the propagation losses. This work proposes radiative WPT, in the 6.78 MHz license-free band, as a hybrid solution to separation-independent WPT, thus mitigating the losses associated with coil separation. Resonant electrically small antennas were fabricated using embroidered textile coils and tuned using L-matching networks, for wearable WPT. The antenna’s efficiency and near-fields have been evaluated numerically and experimentally. The proposed WPT link achieves a stable forward transmission of S 21 > −17 dB and S 21 > −28 dB, independent of coil separation on the XZ and XY planes respectively, in a 27 m 3 volume space. The presented approach demonstrates the highest WPT link efficiency at more than 1-m separation and promises higher end-to-end efficiency compared to UHF WPT.

Text
Separation Independent WPT, Energies - Version of Record
Available under License Creative Commons Attribution.
Download (4MB)

More information

Accepted/In Press date: 17 January 2020
e-pub ahead of print date: 21 January 2020
Published date: February 2020
Keywords: Coils, E-textiles, Electrically small antennas, Internet of things, Wireless energy harvesting, Wireless power transfer

Identifiers

Local EPrints ID: 438327
URI: http://eprints.soton.ac.uk/id/eprint/438327
ISSN: 1996-1073
PURE UUID: 2cb80f62-8969-4b86-bbf6-eb7f51034209
ORCID for Mahmoud Wagih: ORCID iD orcid.org/0000-0002-7806-4333

Catalogue record

Date deposited: 05 Mar 2020 17:31
Last modified: 24 Jul 2021 02:02

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×