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The key feature of the SKA, its enormous collecting area, will be realised by complementing traditional radio telescope designs with aperture arrays. Innovative, efficient and low cost, aperture array antennas provide a large field of view and are capable of observing more than one part of the sky at once.
Used in the low and medium frequency ranges, aperture arrays comprise a large number of small radio wave receptors arranged on the ground. Whereas with a traditional radio telescope radio signals bounce off the surface of a dish and are then captured at the focus, with aperture arrays the radio signals are captured when they first hit the receptor on the ground. The signals from all the elements are then added together electronically, in phase, to synthesise reception beams, and the result is a fast and flexible system.
Two types of aperture arrays are under development for the SKA, low frequency and mid frequency.
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