Thin flexible RF energy harvesting rectenna surface with a large effective aperture for sub µW/cm2 powering of wireless sensor nodes

Wagih, M. and Beeby, S. (2022) Thin flexible RF energy harvesting rectenna surface with a large effective aperture for sub µW/cm2 powering of wireless sensor nodes. IEEE Transactions on Microwave Theory and Techniques, 70(9), pp. 4328-4338. (doi: 10.1109/TMTT.2022.3192532)

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Abstract

The dc power collected by radio frequency energy harvesting (RFEH) absorbing surfaces is limited by their physical aperture. Here, a compact, conformable, and ultrathin sub-1 GHz large-area RFEH surface is proposed based on electrically small ( ka=0.58 ) “wire-type” rectenna elements, with an effective area exceeding its physical aperture size. Using optimized large-signal complex source tuning, the rectifiers achieve up to 36% measured power conversion efficiency (PCE) at 20 dBm. The proposed 15 cm-diameter six-element array generates a 27.5 μ W at 1 V output from a 0.17 μ W/cm 2 incident power density across a 40 k Ω load. Owing to its series connection, the voltage output is boosted, and the load resistance dependence is suppressed enabling over 60% of the maximum RF-to-dc PCE to be preserved for loads between 7 and 100 k Ω , with an area-normalized figure-of-merit nearly 100% higher than previous arrays. The proposed array is integrated with a commercial DC-DC converter and demonstrated powering a Bluetooth low energy (BLE) wireless sensor node (WSN) from an unprecedented incident power density of 0.25 μ W/cm 2 . A practical demonstration using a commercial 3 W, 915 MHz Powercast source is presented, showing an 11 m operation range with a 1 V output and illustrating the impact of polarization mismatch on the proposed array.

Item Type:Articles
Additional Information:This work was supported by the UK Royal Academy of Engineering and the Office of the Chief Science Adviser for National Security under the UK Intelligence Community Post-Doctoral Research Fellowship programme. S. Beeby was supported by the UK Royal Academy of Engineering under the Chairs in Emerging Technologies scheme.
Keywords:Rectenna, rectennas, rf energy harvesting, rectenna arrays, RF energy harvesting arrays, antenna arrays, metamaterial energy harvesting, dipole antennas, matching network elimination, complex-conjugate matching, flexible rectenna arrays, aperture efficiency, compact rectennas, compact antennas, battery-less sensors, wireless sensor networks, RF-powered Bluetooth, energy harvesting Bluetooth Low Energy, antenna effective area, matching network-free rectennas, antenna-rectifier co-design, RF energy harvesting surface, RFEH, microwave power transmission, wireless power transfer, WPT, WPT arrays, WPT metasurface, WPT surfaces.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Wagih, Dr Mahmoud
Authors: Wagih, M., and Beeby, S.
College/School:College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
Research Group:Communication Sensing and Imaging
Journal Name:IEEE Transactions on Microwave Theory and Techniques
Journal Abbr.:IEEE TMTT
Publisher:IEEE
ISSN:0018-9480
ISSN (Online):1557-9670
Published Online:03 August 2022
Copyright Holders:Copyright © 2022 IEEE
First Published:First published in IEEE Transactions on Microwave Theory and Techniques 2022
Publisher Policy:Reproduced in accordance with the publisher copyright policy
Data DOI:10.5525/gla.researchdata.1312

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