There is certainly no shortage of technologies, time and investment being poured into satellite connectivity, as the anticipated 3GPP Release 18 will further integrate satellite non-terrestrial network (NTN) access into 5G. In more recent news, researchers from the University of Glasgow reported having successfully created a 2D metamaterial which they say will lead to improved satellite communications, high speed data transmission and remote sensing.
The innovation in question – an ultrathin 2D surface – uses the properties of metamaterials, referring to structures which have been created to include properties that wouldn’t be seen in naturally occurring materials, to manipulate and convert radio waves across frequencies used by satellites. The metamaterial was published in a new paper in the journal ‘Communications Engineering’.
Satellite connectivity is not perfect. Existing communication antennas are designed to transmit and receive electromagnetic waves either vertically or horizontally. Misalignment between transmitting and receiving antennas can lead to signal degradation, which can have a significant impact.
Current forecasts have been optimistic, as ABI Research predicted the satellite IoT market to receive 26 million connections by 2030; while Omdia said the revenues of satellite IoT are steadily growing, projected to top $1.5 billion by 2030. There are those watching with interest to see how satellite connectivity might be another tool in the kit to improve coverage in areas that struggle, particularly rural areas with limited infrastructure.
The research team has developed a novel 2D metamaterial capable of converting linearly polarised electromagnetic waves into circular polarisation, a breakthrough that could improve communication quality between satellites and ground stations. The use of circular polarisation in satellite communications improves reliability and performance by reducing signal loss caused by polarisation mismatch and multipath interference.
Circular polarisation is particularly resilient against atmospheric disturbances, such as rain fading and ionospheric fluctuations, ensuring more stable connections. This is especially advantageous in mobile applications, as it negates the need for precise antenna orientation.
Additionally, circular polarisation increases channel capacity by employing both right-hand and left-hand circular polarisation. This feature simplifies the design of antennas for small satellites, improves satellite tracking, and ensures robust communication links in demanding conditions, making it well-suited for modern satellite systems.
The metamaterial developed by the team is only 0.64mm thick and consists of small, geometrically-patterned copper cells positioned on a commercially available circuit board, often used in high-frequency communication applications.
The metamaterial’s surface is engineered to enable advanced reflection and repolarisation of electromagnetic waves. In laboratory experiments, signals were transmitted to the metamaterial surface using horn antennas, and the reflected waves were analysed with a network analyser. This allowed the team to measure the device’s efficiency in converting linear polarisation to circular polarisation, with experimental results closely matching the simulated predictions.
“Previous developments in metamaterials have provided new ways for electromagnetic waves to be manipulated in devices with small form factors. However, they’ve largely been limited to narrow bands of the spectrum, which has limited their practical applications so far,” explained Professor Qammer H. Abbasi, the paper’s lead and corresponding author, from the University of Glasgow’s James Watt School of Engineering.
“The metamaterial surface we’ve developed works across a wide range of frequencies across the Ku-, K- and Ka-bands, which span 12 GHz to 40Ghz, and are commonly used in satellite applications and remote sensing,” he added. “This kind of 2D metamaterial surface, capable of the complex task of linear to circular polarisation, can enable antennae to communicate with each other more effectively in challenging conditions.
“It could help satellites provide better signals for phones, and more stable connections for data transmission. It could also improve satellites’ ability to scan the surface of the Earth, improving our understanding of the effects of climate change or our ability to track wildlife migration.”
Professor Muhammad Imran, co-author of the paper, who leads the University of Glasgow’s Communications, Sensing and Imaging (CSI) Hub, said: “This kind of 2D metamaterial surface, capable of the complex task of linear to circular polarisation, can enable antennae to communicate with each other more effectively in challenging conditions. It could help satellites provide better signals for phones, and more stable connections for data transmission. It could also improve satellites’ ability to scan the surface of the Earth, improving our understanding of the effects of climate change or our ability to track wildlife migration.”
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