Advances in Wireless Power Transfer using Large Arrays

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Autori principali: Van der Perre, Liesbet, De Strycker, Lieven, Cox, Bert, Callebaut, Gilles
Natura: Recurso digital
Pubblicazione: Zenodo 2025
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author Van der Perre, Liesbet
De Strycker, Lieven
Cox, Bert
Callebaut, Gilles
author_facet Van der Perre, Liesbet
De Strycker, Lieven
Cox, Bert
Callebaut, Gilles
contents <p>Wireless power transfer (WPT) holds promise for enhancing device autonomy, especially in energy-limited Internet of Things (IoT) systems. A major hurdle remains the rapid decay of received power with distance when using small-aperture antennas. This talk explores how physically large antenna arrays—such as those found in cell-free and extremely large MIMO (XL-MIMO) systems, including RadioWeaves—enable a shift from far-field beamforming to near-field beam focusing, where the received power can remain nearly independent of distance. By shaping distance-adaptive gain patterns, large arrays can concentrate power at device locations while reducing unnecessary exposure elsewhere. This has direct implications for human safety, particularly to the Specific Absorption Rate (SAR)—a key regulatory constraint on electromagnetic energy absorption in biological tissue. Near-field focusing naturally aligns with SAR compliance by minimizing ambient exposure. The second part of the talk presents experimental results from the Techtile testbed—a distributed, large-scale antenna array platform for WPT in the near field. We compare coherent and non-coherent transmit diversity, demonstrating that fully synchronized beam focusing provides a 14 dB gain over non-coherent transmission, closely matching the theoretical 14.9 dB gain for a 31-element array. Furthermore, phase alignment errors below 20° result in less than 1 dB loss, while errors exceeding 40° cause performance degradation beyond 3 dB. This suggests that phase synchronization can be relaxed, and that scaling the number of antennas is a viable strategy to improve wireless power efficiency. While efficiency remains low, this work highlights a regulatory-compliant pathway toward distributed WPT for IoT deployments.</p>
format Recurso digital
id zenodo_https___doi_org_10_5281_zenodo_16316237
institution Zenodo
language
publishDate 2025
publisher Zenodo
record_format zenodo
spellingShingle Advances in Wireless Power Transfer using Large Arrays
Van der Perre, Liesbet
De Strycker, Lieven
Cox, Bert
Callebaut, Gilles
Wireless Power Transfer
Ambient IoT
MIMO
Near Field Communications
<p>Wireless power transfer (WPT) holds promise for enhancing device autonomy, especially in energy-limited Internet of Things (IoT) systems. A major hurdle remains the rapid decay of received power with distance when using small-aperture antennas. This talk explores how physically large antenna arrays—such as those found in cell-free and extremely large MIMO (XL-MIMO) systems, including RadioWeaves—enable a shift from far-field beamforming to near-field beam focusing, where the received power can remain nearly independent of distance. By shaping distance-adaptive gain patterns, large arrays can concentrate power at device locations while reducing unnecessary exposure elsewhere. This has direct implications for human safety, particularly to the Specific Absorption Rate (SAR)—a key regulatory constraint on electromagnetic energy absorption in biological tissue. Near-field focusing naturally aligns with SAR compliance by minimizing ambient exposure. The second part of the talk presents experimental results from the Techtile testbed—a distributed, large-scale antenna array platform for WPT in the near field. We compare coherent and non-coherent transmit diversity, demonstrating that fully synchronized beam focusing provides a 14 dB gain over non-coherent transmission, closely matching the theoretical 14.9 dB gain for a 31-element array. Furthermore, phase alignment errors below 20° result in less than 1 dB loss, while errors exceeding 40° cause performance degradation beyond 3 dB. This suggests that phase synchronization can be relaxed, and that scaling the number of antennas is a viable strategy to improve wireless power efficiency. While efficiency remains low, this work highlights a regulatory-compliant pathway toward distributed WPT for IoT deployments.</p>
title Advances in Wireless Power Transfer using Large Arrays
topic Wireless Power Transfer
Ambient IoT
MIMO
Near Field Communications
url https://doi.org/10.5281/zenodo.16316237