New Technologies for Efficient Wireless Power Transfer at Distance

Lead Research Organisation: Queen's University Belfast
Department Name: Sch of Electronics, Elec Eng & Comp Sci

Abstract

The ability to transmit high power wirelessly over long distances is a potential game changer. In this project we are ambitiously investigating the area of medium power (200 W) medium distance (25 m) microwave wireless power transmission (WPT). Current research on microwave WPT tends to focus on low power "scavenging" techniques, with power levels of < 1mW. This can be useful for applications such as low power sensors, but is unlikely to be disruptive for commonly used wireless devices requiring higher power such as smartphones, or even electric vehicles. Higher powered WPT can be carried out using low frequency inductive coupling techniques, although range is very short (<20 cm). Therefore we see microwave WPT, as the only way of breaking the barrier of longer distance and higher power.

We intend to take commercial Unmanned Aerial Vehicles (Drones) as a demanding, high added value, and un-resolved application example. Current drone technology is battery powered with a flight time of around only 20 minutes. The ability for continuous drone flight would be highly disruptive allowing many new applications for the technology that currently cannot be accessed e.g. first response situations such as delivery of emergency medical supplies. The development of new strategies for medium (<25m) range wireless power transmission (WPT) that permit high efficiency end to end energy transfer delivering up to 200W d.c. power will be a game changer, as it will largely offset the current critical dependence on rechargeable battery technology. This proposal will provide a step change in microwave WPT technology in order to allow continuous powering of arbitrarily located mobile electrical systems entirely wirelessly over distance in an energy effective way. We are not aware of any other research programme that has studied efficient end to end WPT to moving platforms with arbitrary orientation that are capable of both near and far field power delivery ensuring 24/7 endurance.

We intend to address complex research challenges in microwave WPT regarding both transmit and receive rectifying antenna (rectenna) technology. We propose an innovative microwave WPT system that; (i) can transfer power to an object or objects whose position relative to the wireless power source is/are unknown a-priori, (ii) can lie in either the near or the far-field of each other with arbitrary orientation in both line of sight and non-line sight situations (iii) can operate using small, arbitrarily spaced, transmit sub-arrays, to artificially enhance the transmit aperture, since WPT with a single, conventional antenna, requires a massive aperture to produce reasonable efficiency.

This will require major innovations that currently lie beyond state of the art. (a) Near/far field auto focusing tracking antenna array technology, with a high degree of focusing from a distributed array transmitter, allowing for extremely low free space path loss (b) Power amplifiers that can maintain extremely high efficiency over a range of power levels (c) Conformal, orientation agnostic rectifying antenna (rectenna) systems.

In addition to the above we are aware that applying a conformal rectenna around a drone will be highly challenging, if the drone is still to be capable of efficient and stable flight. Therefore staff from the QUB school of Mechanical and Aerospace engineering are also involved in the project to establish novel conformal rectenna flight-ready solutions.

As a grand finale to the research programme we propose to show two high impact practical demonstrations. We intend to show a laboratory measurement of high efficiency microwave WPT, but, to put this research project on the world stage, we plan to show a long duration vertical take-off and landing (VTOL) flight, by flying a drone continuously, powered entirely by microwave wireless power.

Planned Impact

The learnings from our research on Efficient WPT at Distance will be transferred throughout the project to our industrial partners, QinetiQ, Flyte Technologies, Belfast City Council and Nightingale Security who are committed to supporting us during the research and becoming potential users of the research findings.

We will also connect with trade associations in telecoms and aeronautics, such as the GSMA (mobile operators) and the Royal Aeronautics Society (RAeS) to inspire their members to build an ecosystem around and exploit the benefits of 24/7 UAV flights, thus making the UK a global hub for UAV research and development.

We will share the project outcomes with industry and the public via exhibiting and demonstrating WPT at major trade events, such as the International Drone Expo (co-located with the Mobile World Congress in Barcelona every February)

We also intend to organise a "WPT for UAV" one-day boot camp in three UK regions (Scotland, Greater London and Northern Ireland) to educate and inspire professionals from multiple sectors, such as agriculture, environment, city councils, law enforcement, health/medical, blue lights, sports, event security, video-based media and film producers, about the new opportunities offered by continuous drone operation made possible by WPT.

We will also send our researchers to networking meetings, such as technology "meetups" that take place on regular basis throughout the UK, and to discussions with industry, academic and public authorities, such as the CAA and NATS.

We will further disseminate the results via the QUB Media Team who have access and contacts with hundreds of mainstream and scientific media outlets in the UK and overseas. This will be very relevant to the results of WP5 where we intend to break the world record for the longest duration autonomous vertical take-off and landing (VTOL) flight, by flying a drone continuously for longer than 23 hours.

The ECIT institute, host of the Centre for Wireless Innovation where the project will take place, is directly supported by a Commercial Team whose members have built strong and significant relationships with industry across all continents, and feature regularly in articles from tech and general news outlets. This project will be included in the portfolio of topics which the Commercial Team publicises.

This project will enhance UK's academic and commercial reputation in the field of advanced wireless communications, signal processing and specifically power-type applications. The proposed research will devote to educating and training highly skilled engineers so that they acquire world-leading expertise vital to the demands of their future career paths. At the same time, the academic researchers on this project will gain from a highly commercial emphasis at QUB's School of Aerospace Engineering and the ECIT institute, to develop a well-balanced technical expertise in close collaboration with the industry partners. The opportunity to engage directly with staff from Qinetiq and Flyte Technologies will expose the project's researchers to world-leading and wireless communications and UAV expertise.

When looking towards educating the next generation of researchers, this research programme will be perfect for demonstrations to schools and University open days. Dr Neil Buchanan (PI) is currently responsible for marketing QUB Electronic Engineering to schools and it is anticipated that the research project will be publicised at 7 events per year (4 regional schools events, 2 university open days, 1 teacher's dinner event).

Prosperity Outcomes: We see this project fulfilling the following: Productive Nation: P1, Healthy Nation: H1, Connected Nation: C2, C3.

Publications

10 25 50
 
Description The main areas of focus have been the development of various components required to achieve a suitable state of readiness for a complete end to end wireless power transmission (WPT) demonstration. These components include the transmit/receive antenna arrays, Transmit power amplifiers, and receive rectifiers. In all cases the components aim to achieve a level of novelty or increase in performance above the state of the art. Key findings are as follows: (1) A Novel power amplifier configuration has been produced which allows a low power pilot signal to be received in the presence of the high power WPT signal. This does not require any transmit/receive isolation circuits and is capable of producing the required phase conjugation for retrodirective operation of the transmit array with efficiencies >80% (2) A new Transmit Array structure has been implemented which includes more lightweight and better aligned elements, with a smaller and lighter matching structure. The elements are also enclosed in a partial square cavity, which was found to increase the transmitted power directivity by around 5%, which is an impressive increase when attempting to achieve a high WPT end to end efficiency. (3) A receive array has been designed and fabricated, using cavity backed helical elements which improves the received power by around 3%. The helices were made of 1mm diameter wire to have less weight, to allow better integration with applications such as WPT to drones. (4) Several High efficiency power amplifiers have been designed, specifically demonstrating higher efficiency over a wide range of power levels, compared to state of the art. This was achieved by implementation of a novel feedback circuit, amongst others. (5) A new differential topology for high power rectification has been designed and tested. The differential topology is a very significant step forward as it allows the rectifier to integrate directly to differential antennas such as dipoles without the requirement for baluns, thus maximising efficiency. The circuit has been demonstrated to operate with high efficiency (>70%) for RF input power levels up to 1.6W. These rectifiers also have the advantage of being able to be produced from low cost off the shelf components. (6) Higher power rectifiers have been implemented using reverse configured power amplifiers as rectifiers. A rectifier has been fabricated and measured which was found to produce >75% efficiency at power levels of 10W. In addition efficiency >70% was produced over a dynamic range of 8 dB, which is a significant result for such a rectifier. (7) An extensive study has been carried out of the suitability of off-the-shelf diodes as RF rectifiers, resulting in rectifiers that can operate at up to 2W with high efficiency. These rectifiers are extremely low cost and would be well suited to the power densities required for ground based rectennas for applications such as the solar power space satellite which will require billions of mass-produced rectenna elements.
Exploitation Route Primarily the research has targeted an end application of wirelessly powered drones, to allow continuous flight without recharging, however our industry/government engagements in the project have shown other areas where the technology can have significant impact. One very promising application area is the solar power space satellite. This will allow solar power to be beamed to earth via a satellite, allowing 24/7 solar power. The WPT power densities at the receive rectenna of 200 W/m2 produced in this EPSRC project are very compatible with the solar power space satellite. The positive consequence of this is that we were in a unique position to successfully obtain almost £0.5M of funding to provide the first practical demonstration of retrodirective antenna technology for the solar power space satellite. This is a significantly high impact follow on project working towards UK government Net Zero targets.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Digital/Communication/Information Technologies (including Software),Electronics,Energy,Environment,Transport

 
Description The findings of the project has provided a new engagement with Satapps Catapult, Harwell, where a new development project with a total funding of £1M has been obtained between three partners (Satapps Catapult, Imperial College London and Queens University Belfast). The project is funded by UK Government Department for Business, Energy & Industrial Strategy. The project will develop a self steered antenna demonstration for the proposed solar power space satellite, which has the aim of beaming power harnessed by the sun at a satellite, back to earth via a microwave beam, offering 24/7 clean energy in the gigawatt levels. Queens University Belfast will be the first worldwide to demonstrate such technology at the required power densities. The resulting impact is highly significant as the technology can be directly applied to the next phase of the solar power space satellite, which will include a high altitude platform demonstration and in-space wireless power transmission experiment.
First Year Of Impact 2022
Sector Electronics,Energy,Environment
Impact Types Societal,Economic

 
Description CASSIOPeiA Antenna with Steering Scaled Indoor Experiment (CASSIE)
Amount £999,512 (GBP)
Organisation UK Space Agency 
Sector Public
Country United Kingdom
Start 04/2023 
End 04/2025
 
Description BT Research Labs, Adastral Park, Martlesham 
Organisation BT Group
Department BT Research
Country United Kingdom 
Sector Private 
PI Contribution Presentation "Secure Intelligence Wireless Power Transfer (WPT)" given online 8 Mar 2021. Bi Yearly industrial collaborator progress reports are disseminated on the EPSRC project to BT labs
Collaborator Contribution Discussions of how wireless power transfer could be incorporated in to BT's future research plans and influence future product lines
Impact Presentation "Secure Intelligence Wireless Power Transfer (WPT)" given online 8 Mar 2021. Bi Yearly industrial collaborator progress reports
Start Year 2021
 
Description Belfast City Council (UK) 
Organisation Belfast City Council
Country United Kingdom 
Sector Public 
PI Contribution Provision of an annual report sent on 17 Dec 2020. Continuous collaboration with the ECIT institute on a higher level as part of initiatives such as Belfast regional City deal
Collaborator Contribution Networking/publicity as part of initiatives such as Belfast regional City deal
Impact Networking/publicity as part of initiatives such as Belfast regional City deal
Start Year 2019
 
Description Collaboration with Chargifi as a project partner 
Organisation Chargifi
Country United Kingdom 
Sector Private 
PI Contribution Providing a new technology for mobile device charging
Collaborator Contribution Providing a potential business plan where mobile charging technology can be setup as a global, profitable resource
Impact NDA between QUB and Chargifi
Start Year 2019
 
Description Nightingale Security (USA) 
Organisation Nightingale Security
Country United States 
Sector Private 
PI Contribution Provision of an annual report sent on 17 Dec 2020
Collaborator Contribution The partner is a potential end user of the technology - we expect further contributions towards the end of the project
Impact No outcomes to date
Start Year 2019
 
Description QinetiQ plc (UK) 
Organisation Qinetiq
Department QinetiQ (Malvern)
Country United Kingdom 
Sector Private 
PI Contribution Provision of a part time PhD in the area of distributed wireless power transfer to a staff member at QinetiQ. Provision of 6 monthly progress reports on the project.
Collaborator Contribution Progress meetings are held every 2 weeks. Significant technical expertise has been offered by the partner to the project, which is already having a significant impact on the research results being achieved.
Impact Internal PhD reports
Start Year 2019
 
Description Satellite Applications Catapult, Harwell 
Organisation Satellite Applications Catapult
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution Significant discussions via meetings (online and in person on 28-2-23) leading to a successfully funded proposal to UK Gov BEIS and UK space agency, to develop the solar power space satellite. Project to start in April 2023
Collaborator Contribution Coordination and project management of a proposal to UK Gov BEIS and UK space agency, to develop the solar power space satellite.
Impact Successfully funded proposal to UK Gov BEIS and UK space agency, to develop the solar power space satellite. Project to start in April 2023 Involving Satapps Catapult as lead project management, QUB and Imperial College. Overall project funding of £999,512
Start Year 2021
 
Description "Wireless power Transfer and Space Antennas" Presentation at QUB Centre for Wireless Innovation Annual Symposium, Creating Future Connected Spaces, ECIT, QUB May 2021 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Follow on engagement with Satapps Catapult centre, potentially leading to exciting new opportunities in solar power space satellite research. A significant (£0.5M) source of research funding is currently being explored to support this. The solar power space satellite research promises to deliver solar power from space, via Microwave wireless power transfer, addressing very significant environmental needs. It was clearly recognised that the technology being developed in this EPSRC project could offer significant enhancements in the efficiency of wireless power transfer from space.
Year(s) Of Engagement Activity 2021
URL https://www.qub.ac.uk/ecit/Events/AnnualCWISymposium2021-CreatingFutureConnectedSpaces.html
 
Description Exhibition stand (virtual) at European Microwave Week 2020 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Virtual Exhibition stand at European Microwave week 2020 - Held as virtual event - 10 January 2021 until 15 January 2021
Year(s) Of Engagement Activity 2021
URL http://wp.lancs.ac.uk/epsrcrffor6gcluster/
 
Description Industrial Meeting with Spirit Aerospace at ECIT Belfast, 4th May 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Presentation and discussion on potential collaborations on Novel Antenna concepts for High Altitude Platforms (HAPS)
Year(s) Of Engagement Activity 2022
 
Description Industrial Visit to Taoglas, Antenna Manufacturer, Co. Wexford, Ireland, 10th Aug 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact An in-person visit to Taoglas to facilitate presentations and discussions about future collaborations on custom antenna designs
Year(s) Of Engagement Activity 2022
URL https://www.taoglas.com/
 
Description Invited Presentation "Wireless power Transfer and Space Antennas" Spacebar, AstroAgency, 26th May 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Invited Presentation "Wireless power Transfer and Space Antennas". Meaningful follow on discussions with the space sector within an active Q&A.
Year(s) Of Engagement Activity 2022
URL https://twitter.com/theAstroAgency/status/1527335984374767617?s=20
 
Description Meeting to discuss Wireless Spectrum Centre in Wales (QinetiQ) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The meeting was set up to discuss a proposed wireless spectrum centre in Wales. The new centre will open up the possibility of testing experimental wireless prototypes, without the requirememnt for lengthy licensing type apporvals. This EPSRC project has been chosen as one of several pilot experiments that will be conducted on the site. Essentially this means that we could be the first customer to use the spectrum centre which will result in significant publicity for the project, which will be used as an ideal example of the type of testing offered by the new centre. It is also crucial for this project that we have access to this test facility to allow a full scale test of wireless power to a drone, as we do not have this type of facility at the University.
Year(s) Of Engagement Activity 2020
 
Description Membership of Space Energy Initiative 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Discussions shaping future space energy Initiatives via quarterly meetings attended by significant industry and policymakers
Year(s) Of Engagement Activity 2022,2023
URL https://spaceenergyinitiative.org.uk/
 
Description Presentation by Dr Dmitry Zelenchuk (QUB) at SPRINT R&I SEMINAR: "ANTENNA DEVELOPMENT FOR SATCOMMS IN 2030", Mar 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact Promotion of wireless power transfer in space, leading to potential further opportunities, such as the solar Power Space Satellite.
Year(s) Of Engagement Activity 2022
URL https://sprint.ac.uk/events/online-sprint-ri-seminar-antenna-development-for-satcomms-in-2030/
 
Description Presentation to BT proposed use of Wireless Power transfer within 5G in Belfast 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Introductory session, with a section head at BT, to explore using Wireless Power Transfer technology within 5G networks in Belfast
Year(s) Of Engagement Activity 2021
 
Description Spacebar, AstroAgency "Wireless power Transfer and Space Antennas" Invited speaker 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact "Wireless power Transfer and Space Antennas" Presentation and Panel Discussion - attended by 100+ space enthusiasts and
professionals monthly. Spacebar runs these events to allow people to network, while conversing about current (and sometimes
controversial) topics. Previous speakers include Helen Sharman, Tim Peake, Dr Kevin Fong, Dr Lucy Roberts, and many others
Year(s) Of Engagement Activity 2022
 
Description UK Space Agency visit of CEO Paul Bate to QUB Centre for Wireless Innovation, Feb 2022 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Presentation of Wireless power transfer project to UK space agency to scope out further funding and business opportunities for wireless power transfer in space.
Year(s) Of Engagement Activity 2022
 
Description Visit to Mobile World Congress 2020 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Prmoting the project to relevant industires at the Trade show
Year(s) Of Engagement Activity 2020
 
Description Visit to Satapps Catapult, Harwell for workshop "Space Solar WPT: linking projects to the roadmap" 28 Feb 2023 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Follow up plan involving spin out company "Space Solar Ltd" to produce space solar power wireless power transmissions practical demonstrations.
Year(s) Of Engagement Activity 2023
 
Description Work experience visit to QUB from lower sixth form school pupils 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact 21 lower sixth form pupils visited from 6 schools in Northern Ireland. They visited QUB for 2 days work experience on 22-23rd Jan 2020. During this time they spent 1/2 day with the PI of this EPSRC project learning to build simple breadboard circuits, demonstrating some of the priciples of wireless power transfer. At this session, the PI presented to them the overall aims of the EPSRC project.
Year(s) Of Engagement Activity 2020