Giant space antenna designed to beam 5G to Earth

Cambridge Consultants is working to deliver the largest airborne communications antenna available commercially.

The technology consultancy and product-development firm, which is part of Capgemini, has built a functioning, scaled-down version of a wireless antenna designed to beam connectivity from the sky. The prototype, announced this month, is part of a four-year project with UK-based start-up Stratospheric Platforms Limited (SPL).

SPL is developing a High-Altitude Platform (HAP) and communication system that’s designed to deliver affordable, fast connectivity. The HAP aircraft system, as envisaged, would beam its Internet from the stratosphere, which is the second major layer of Earth’s atmosphere. The aircraft, with a 60-meter wingspan, would be powered by hydrogen and could deliver nine days of flight stamina. Each HAP could supply coverage over an area of up to 140 kilometres in diameter, and around 60 aircraft could blanket a country the size of the U.K., according to Cambridge Consultants.

“Operating at a fraction of the cost of building and maintaining terrestrial infrastructure, and with minimal environmental impact due to its zero-emission hydrogen power system, such a fleet could rewrite the economics of mobile broadband,” the company says in its press release announcing the project’s progress.

The antenna itself would measure three-meters square and weigh 120 kilograms.

One of the key conceptual differentiators that Cambridge Consultants touts is the antenna’s highly shapeable beam pattern. Each HAP would produce 480 steerable beams that would allow coverage to be concentrated on specific physical areas, such as a freeway or a railroad, for example.

The company sees its airborne antenna as something much more flexible than classical fixed masts found in today’s mobile networks. The company has found that using Fibonacci spirals – a sequential pattern found in nature – for the coverage area, rather than traditional hexagonal cells, can improve traffic performance by 15%.

“Projecting cells from the sky enables service providers to dynamically change location and power allocation to meet changing end-user demands,” Cambridge Consultants says on its website.

Traditional spot beams are used in satellite transmissions and allow satellites to share frequencies. Their signals can be directed only at a limited geographic area, which allows direct broadcast satellite television to deliver a local broadcast, for example. Different data signals can use the same, limited, frequencies in different parts of the coverage area without interfering.

The Cambridge Consultants/SPL project takes that one step further. Their digital beamforming technology will be able to “paint” coverage as specifically as targeting an individual vehicle or following a physical boundary.

“A unique, wholly digital beamforming capability gives massive flexibility in how services are deployed, allowing in-flight reconfiguration to deliver services beyond the reach of conventional fixed terrestrial networks,” Cambridge Consultants said. “This includes following mobile users, including trains and autonomous vehicles, and providing coverage exactly where required, for example ending at national borders.”

SPL completed its first successful test trial in September of this year. Rollout of the first commercial service is expected to begin in Germany in 2024. Deutsche Telekom is reportedly a backing partner.

In the bigger picture, drone Internet is capturing imaginations. SoftBank is planning a drone-delivered IoT and internet service, for example. The Japanese multinational company has been working alongside California’s AeroVironment to develop a drone with a wingspan of 79 meters. In 2019, SoftBank said it’s aiming for service in 2023.

Internet balloons, too, can operate in the stratosphere. Alphabet’s Loon balloon project successfully delivers Internet from about 12 miles up, for example.