Ever since I was a little kid, I was fascinated with the many wonders of our planet and the enormity of the Universe in which it dwells. I often wondered if there was a finite “edge” to the Universe or if it extended into infinity. If there was an edge, what could possibly be beyond that? Blank darkness? Another Universe with more planets and other people? If it was infinite, then what? Could it really be possible that there is no end to something? My young mind just could not get a grasp of that concept. Growing up in an era without the internet, I could only fuel my imagination with movies, books and the news.
Now, many years later, working for Corporate Marketing at Altair Engineering, imagine my delight when I was tasked to work on a story about the Square Kilometer Array (SKA) project. This is a project led by the SKA Organization from Jodrell Bank Observatory in the UK, supported by 11 member countries – South Africa, Australia, Canada, China, Germany, India, Italy, New Zealand, Sweden, The Netherlands and the United Kingdom. The SKA, a collection of various types of antennas, seeks to challenge Einstein’s seminal theory of relativity to the limits, how the very first stars and galaxies formed just after the Big Bang, the study of dark energy and the vast magnetic fields in the cosmos, and the age old question “Are we alone in the Universe?” as some of its key scientific goals.
Construction of the SKA will be completed in two phases: Phase 1 (SKA1) is being built in South Africa and Australia and is estimated to be completed in 2023 and; Phase 2 (SKA2) will start after SKA1 and will take the project into other African countries, with the Australian component also being expanded. For Phase 1 the 64-dish MeerKAT precursor array, which is currently under construction and expected to come online in a few years’ time, will be integrated into SKA1 MID, with the construction of another 190 dishes.
Radio frequency interference (RFI) mitigation for the SKA EM Environment
The proximity of adjacent antennas and other systems can result in unwanted inter-coupling which needs to be minimized by first identifying the coupling mechanisms, and then applying measures to improve isolation, for example shielding or re-routing of cables. These on-site radio frequency (RF) coupling investigations can only be done after installation. During the design, planning and installation stages such characterization of the electromagnetic (EM) environment has to be done on scale models and through simulations.
Characterization of Electromagnetic (EM) Environment for the SKA through simulation
The electrical size of the structure and the broad spectrum covered in this case requires significant computational resource requirements. Altair FEKO, an electromagnetic simulation software tool, based on state of the art computational electromagnetics (CEM) techniques, was run at the Centre for High Performance Computing (CHPC) in Cape Town and the simulations were completed in a matter of days. The validated FEKO model could then be used to do rigorous RFI studies and make design, layout, shielding and bonding recommendations to mitigate the interference between these extremely sensitive telescopes.
“FEKO modelling on the Cape Town CHPC has been pivotal in my RFI mitigation research at Stellenbosch University for the MeerKAT Telescope. We have successfully validated dish scale models with measurement and continue to use FEKO to study EM induced current paths and provide RFI mitigation recommendations to SKA South Africa” said Dr Gideon Wiid, Lecturer, E & E Engineering, University of Stellenbosch, South Africa.
When completed, the SKA will be 10,000 times faster and 50 times more sensitive than any existing radio telescope. It will be so sensitive that it will be able to detect an airport radar on a planet tens of light years away. Its central computer will have the processing power of about one hundred million PCs and the dishes of the SKA will produce 10 times the global internet traffic.
While we are extremely fortunate to live in an era of abundant resources with a wealth of information just a mouse click away, there is still so much more to learn and discover. The SKA is a perfect example of technology innovation that seeks to answer questions and solve mysteries about the Universe we live in. I certainly hope it will motivate and fire the imagination of many young minds as they look up and wonder at the night sky as I often did.
(photo credits: SKA site – www.ska.ac.za )
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