An essential building block for next-generation phased array antennas, developed by Thales Alenia Space (TAS) in the frame of the European Space Agency’s Technology Development Element programme, proudly presented by TAS’s antenna expert Benoit Lejay.
While traditional antennas rely on mechanically tilting their dishes in order to maintain contact with a satellite, phased array antennas steer their signals electronically. This technology enables more precise and faster pointing and allows an antenna to communicate with multiple satellites at the same time without any moving parts.
However, with satellite technology and its applications evolving faster than ever, the current radio frequency ‘highways’ carrying information to and from satellites – the Ku and Ka bands – are becoming increasingly congested.
Expanding the available range of frequencies to the extremely-high-frequency region of the electromagnetic spectrum leads to more bandwidth, meaning more data can be transmitted by a network in a given time.
At their site in Toulouse, France, Thales Alenia Space develop key building blocks for next-generation phased array antennas operating at a very special frequency – the Q/V-band, which offers more bandwidth than the more widespread Ku- and Ka-bands.
More than ten years ago, the Aldo Paraboni technology demonstration payload on ESA’s Alphasat mission became the first instrument to use Q/V-band communications on a commercial satellite over Europe. Since then, several satellites with Q/V-band payloads have emerged in different orbits, offering extremely high throughputs.
Václav Valenta, ESA’s engineer and phased array expert, talks about one of the key enabling technologies: “A major breakthrough has been the maturity of Gallium Nitride (GaN) semiconductor devices, which enable compact high-power transmitters. These transmitters are now small enough to be used in large numbers within phased array antennas — a key technology already common at lower frequencies and now becoming applicable in the Q-band as well.”
But building phased arrays at extremely high frequencies comes with challenges. “To make the phased array work, hundreds of high-power transmitters must be placed very close together — depending on the orbit, this can be even a fraction of a wavelength,” explains Václav. “At these frequencies, that distance can be only a few millimetres, which makes the integration of complex functions extremely challenging.
“Then there is the challenge of thermal management. With so many high-power elements packed into a small area, new and efficient methods were needed to remove heat from critical components.”
In a recent activity funded by ESA’s Technology Development Element, Thales Alenia Space (TAS) integrated many innovative technologies in one, developing a demonstrator of a radio frequency ‘front end’ for a Q-band phased array antenna – a key building block encompassing all the electronic components on the antenna’s receiving end.
Benoit Lejay, antenna expert and lead of the activity at TAS, comments: “In this great achievement, we have demonstrated the feasibility of the key building block required for next-generation phased array antennas. Moreover, we’ve shown that our industrialised manufacturing processes are suitable for the building of extremely-high- frequency front ends, which underlines the outstanding position of TAS in the area of phased array antennas.”