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Engineers from the European Space Agency\u2019s Radio Frequency Equipment and Technology section successfully tested a new radio beamforming concept \u2013 developed, patented and prototyped in-house in ESA\u2019s Microwave Laboratory.<\/p>\n
This beamforming prototype, tested in ESA\u2019s Antenna Laboratory, demonstrates a new way of controlling radio signals in an antenna array to focus multiple beams in desired directions, using far fewer components than traditional systems with similar capabilities do today.<\/p>\n
The key to the success of this innovative idea lies in a relatively simple concept \u2013 natural geometrical symmetry of antennas and radio beams. \u00a0\u00a0\u00a0<\/p>\n
Listening to the radio, watching TV, making a mobile phone call, using satellite navigation or forecasting the weather \u2013 without antennas that enable transmission and reception of electromagnetic waves, these everyday activities would be impossible.<\/p>\n
With the unstoppable growth of the amount of data, users and a continuous technological development, the complexity of antennas is increasing tremendously.<\/p>\n
Instead of using a single high-power, mechanically steerable antenna, modern systems employ a set of multiple, low-power antennas working together to steer the radio waves in desired directions \u2013 without pointing the antenna itself. Such \u2018antenna arrays\u2019 can contain hundreds or even thousands of individual antenna elements \u2013 each of them fed separately with signals generated by a \u2018beamformer\u2019, with precisely calculated timing.<\/p>\n
Hugo Deberg\u00e9, ESA\u2019s microwave engineer, explains: \u201cBy changing the signal\u2019s phase and amplitude for each individual element in an array, we can steer the resulting signal in a desired direction. We don\u2019t do this by physically tilting the antenna, as we used to do, but instead by adjusting the electrical signals we feed into individual antenna elements.<\/p>\n
\u201cThe new beamforming technology we are testing builds on two separate discoveries, both patented by ESA. The first one is a concept known for over 10 years \u2013 it showed that if your antenna array is symmetrical (which is likely the case), you can treat symmetrical elements as couples and simplify the calculation of individual signals in a digital processor. By feeding each couple with signals that are complementary to each other, you will have the same functionality as if you were controlling them as two independent elements.\u201d<\/p>\n
If you think of an antenna as a clock face, then the elements located at 12 and 6 o\u2019clock would form a couple, and the elements at 3 and 9 o\u2019clock would form another. If we draw the line of symmetry going across the clock in a slightly different place, the 12 and 9 o’clock elements would form a couple, and the 3 and 6 o’clock elements would form another one.<\/p>\n
Hugo adds: \u201cThe second innovation, patented by ESA in 2023, focuses on the way the electrical signals for antenna couples are created by an electrical circuitry. We came up with a way to simplify the electrical circuit within the system so that it allows us to remove half the components and still maintain the same functionality \u2013 this is a major improvement, drastically reducing the overall complexity, mass and power consumption of the entire setup, while doing the exact same job.\u201d<\/p>\n
Antennas are fundamental for every spacecraft, allowing the transfer of communication or navigation signals \u2013 transmitting and receiving radar radio waves to observe planets, receiving scientific data from deep space or measuring altitude during entry descent and landing missions.<\/p>\n
As with any spacecraft or instruments destined for space, a prototype like this one needs to be tested in an environment that recreates certain conditions found in space as closely as possible.<\/p>\n
For antennas, this is done in anechoic chambers \u2013 shielded rooms designed to isolate the device under test from the outside world, simulating the endless void of space.<\/p>\n
An anechoic chamber\u2019s thick metal walls block all outside signals such as radio, TV broadcasts, Wi-Fi and mobile network. On the inside, the walls are covered with pyramid-shaped foam protrusions that absorb any signals produced by the device being tested, creating a space without echoes to ensure that only the contributions of the antenna are measured.<\/p>\n
The Hybrid European Radio Frequency and Antenna Test Zone (HERTZ), part of ESA\u2019s Antenna Testing Facility at ESTEC in the Netherlands, is one such chamber.<\/p>\n
\u201cThe concept demonstrated here in HERTZ is very convincing, but this is just the beginning,\u201d adds Vaclav Valenta, ESA\u2019s microwave engineer a co-inventor of the concept.<\/p>\n
\u201cNow, this patented beamforming concept and associated experimental results are available to industries in ESA member states for space use, free of charge. They can integrate this solution into a single microchip that will allow for more compact and low-power solutions for both space and ground applications.<\/p>\n
\u201cSince the concept attracts a lot of attention among our industrial partners, a dedicated R&D program will be initiated soon to further increase the technology readiness. This will be implemented in the frame of an Open Space Innovation Platform (OSIP) call \u2013 a tool for the commercial maturation of ESA inventions,\u201d concludes Vaclav.<\/p>\n
Through the cooperation of the Antenna and Microwave laboratories, ESA covers end-to end engineering capabilities from design and simulation to prototyping and testing. All this is done within one division team, allowing ESA engineers to quickly demonstrate new concepts. This suite of facilities is also available for industries and research institutes for their own R&D purposes.<\/p>\n<\/p><\/div>\n