Physically Large Apertures for Wireless Power Transfer : Performance and Regulatory Aspects
Deutschmann, Benjamin J.B. ; Muehlmann, Ulrich ; Kaplan, Ahmet ; Callebaut, Gilles ; Wilding, Thomas ; Cox, Bert ; Van Der Perre, Liesbet LU ; Tufvesson, Fredrik LU
; Larsson, Erik G.
and Witrisal, Klaus
(2026)
In IEEE Wireless Communications
33(2).
p.126-133
- Abstract
Wireless power transfer (WPT) is a promising service for the Internet of Things (IoT), providing a cost-effective and sustainable solution to deploy so-called energy-neutral devices on a massive scale. The power received at the device side from a conventional transmit antenna with a physically small aperture decays rapidly with the distance. New opportunities arise from the transition from conventional far-field beamforming to near-field beam focusing. We argue that a physically large aperture, that is large with respect to the distance to the receiver, enables a power budget that remains practically independent of distance. Distance-dependent array gain patterns allow focusing the power density maximum precisely at the device location,... (More)
Wireless power transfer (WPT) is a promising service for the Internet of Things (IoT), providing a cost-effective and sustainable solution to deploy so-called energy-neutral devices on a massive scale. The power received at the device side from a conventional transmit antenna with a physically small aperture decays rapidly with the distance. New opportunities arise from the transition from conventional far-field beamforming to near-field beam focusing. We argue that a physically large aperture, that is large with respect to the distance to the receiver, enables a power budget that remains practically independent of distance. Distance-dependent array gain patterns allow focusing the power density maximum precisely at the device location, while reducing the power density near the infrastructure. Physical aperture size is a key resource in enabling efficient yet regulatory-compliant WPT. We use real-world measurements to demonstrate that a regulatory-compliant system operating at sub-10 GHz frequencies can increase the power received at the device into the milliwatt range. Our empirical demonstration shows that power-optimal near-field beam focusing inherently exploits multipath propagation, yielding both increased WPT efficiency and improved human exposure safety.
(Less)
- author
- Deutschmann, Benjamin J.B.
; Muehlmann, Ulrich
; Kaplan, Ahmet
; Callebaut, Gilles
; Wilding, Thomas
; Cox, Bert
; Van Der Perre, Liesbet
LU
; Tufvesson, Fredrik
LU
; Larsson, Erik G.
and Witrisal, Klaus
- organization
- publishing date
- 2026-04-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Beam focusing, channel measurements, energy-neutral, Internet of Things, near-field, wireless power transfer
- in
- IEEE Wireless Communications
- volume
- 33
- issue
- 2
- pages
- 8 pages
- publisher
- IEEE - Institute of Electrical and Electronics Engineers Inc.
- external identifiers
-
- scopus:105032219841
- ISSN
- 1536-1284
- DOI
- 10.1109/MWC.2025.3636246
- language
- English
- LU publication?
- yes
- id
- 0d47d2f3-5c09-489c-bcfa-a08772b07794
- date added to LUP
- 2026-05-04 14:22:49
- date last changed
- 2026-05-04 14:24:00
@article{0d47d2f3-5c09-489c-bcfa-a08772b07794,
abstract = {{<p>Wireless power transfer (WPT) is a promising service for the Internet of Things (IoT), providing a cost-effective and sustainable solution to deploy so-called energy-neutral devices on a massive scale. The power received at the device side from a conventional transmit antenna with a physically small aperture decays rapidly with the distance. New opportunities arise from the transition from conventional far-field beamforming to near-field beam focusing. We argue that a physically large aperture, that is large with respect to the distance to the receiver, enables a power budget that remains practically independent of distance. Distance-dependent array gain patterns allow focusing the power density maximum precisely at the device location, while reducing the power density near the infrastructure. Physical aperture size is a key resource in enabling efficient yet regulatory-compliant WPT. We use real-world measurements to demonstrate that a regulatory-compliant system operating at sub-10 GHz frequencies can increase the power received at the device into the milliwatt range. Our empirical demonstration shows that power-optimal near-field beam focusing inherently exploits multipath propagation, yielding both increased WPT efficiency and improved human exposure safety.</p>}},
author = {{Deutschmann, Benjamin J.B. and Muehlmann, Ulrich and Kaplan, Ahmet and Callebaut, Gilles and Wilding, Thomas and Cox, Bert and Van Der Perre, Liesbet and Tufvesson, Fredrik and Larsson, Erik G. and Witrisal, Klaus}},
issn = {{1536-1284}},
keywords = {{Beam focusing; channel measurements; energy-neutral; Internet of Things; near-field; wireless power transfer}},
language = {{eng}},
month = {{04}},
number = {{2}},
pages = {{126--133}},
publisher = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
series = {{IEEE Wireless Communications}},
title = {{Physically Large Apertures for Wireless Power Transfer : Performance and Regulatory Aspects}},
url = {{http://dx.doi.org/10.1109/MWC.2025.3636246}},
doi = {{10.1109/MWC.2025.3636246}},
volume = {{33}},
year = {{2026}},
}