New Technologies for Efficient Wireless Power Transfer at Distance

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.

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.