Radio frequencies and bandwidths are a hotly contested resource the world over. They are mainly used for terrestrial applications like mobile phones, TV and many others. The required bandwidth resulting from these application effect also the satellite domain, where the bandwidth needs for traditional satellites and the new mega-constellations, is enormous. Now, for the first time in Graz, satellite signals at 75 GHz from an altitude of 500 kilometres have been received on the roof of JOANNEUM RESEARCH. The signals are transmitted by the W-CubeSat that was launched on the 30th of June 2021 into polar orbit as a part of the payload aboard a Falcon 9 rocket from Cape Canaveral. The aim is to transmit 75 GHz (W-band) and 37.5 GHz (Q-band) signals and generate new knowledge of atmospheric attenuation during the propagation of radio signals at such high frequencies.
New Data Highways
The required capacity for data transmission today is continuously increasing. All over the world, research is being conducted on new data highways for digital consumption. Alongside increasingly strict regulations, use is being made of higher and higher frequencies. New frequencies are now being tested in order to connect the new, powerful satellites to the internet. This sounds simple, but it is actually complex since the short wavelengths are heavily affected by weather events and not every frequency range is suitable for transmission.
Michael Schmidt, telecommunications engineer, and expert for space communication at DIGITAL, explains, “In a way, there is a competition to see who can make use of the very high frequencies.”
Breaking New Technical Ground
While the so-called Ka and Ku band frequencies (20/30 and 12/14 GHz) are already heavily occupied, there are several research activities and experimental satellite payloads in the Q/V band ranges (40/50 GHz). The W-band (71-76 GHz for satellite communication) was, until recently, considered to be a long way off.
As Schmidt said, “Although there have been attempts by international players, no results have been published so far.”
The team of researchers in Graz, together with the international team, have been conducting pioneering work with the signal reception and the start of evaluation phase:
“The measurement phase starts now with the first signals that we receive from the W-CubeSat. We need to understand the new band in order to use it to its full potential. The results will make it possible to create models that will enable the planning and dimensioning of future satellite links and to run them efficiently”, project manager Schmidt reports. “We have broken new technological ground and are at the forefront in Europe”, Schmidt enthused.
The development of the WCubeSat took place in Finland. The mini satellite can be seen from Graz five to six times per day.
International Collaboration
The receiving antenna was developed by the project partner Luis Cupido Technologies, the satellite by Reaktor Space Lab, Fraunhofer and VTT Technical Research Centre of Finland, and the received data is evaluated by the team at JOANNEUM RESEARCH, who also lead the project, and the University of Stuttgart.
Financing
The project was financed by the Federal Ministry for Climate Protection, Environment, Energy, Mobility, Innovation and Technology to the tune of approximately one million Euros after a competitive international ESA tender. The Austrian contribution is thus the largest in the project consortium. The countries of Finland, Germany, and Portugal also support the project with a total of two million Euros.