Model and full-scale study of soil berm for Karoo array telescope shielding

The Karoo region in the Northern Cape of South Africa has been chosen to host the country's Square Kilometre Array (SKA) [1] telescope core due its low radio frequency interference (RFI) levels. With the construction of the Karoo Array Processor Building (KAPB), self-generated radio frequency interference (RFI) and its potential propagation into telescopes has attracted close attention throughout the design and development phases of the project. During the construction of the KAPB, excavated soil was used to form a berm. This paper presents the results of a study of the berm properties using laboratory, physical and computational scale models along with site field measurements. Real soil dielectric properties are incorporated into well-known computational electromagnetic modelling (CEM) packages. A conducting ground plane serration technique is proposed in the model to simulate infinite conditions. The models form the basis of simplified CEM versions of the real berm. The laboratory measurements closely match the CEM models to the point where the CEM models can be used for operational studies as well as planning measurements. Measurements of this berm were made using an unmanned aerial vehicle (UAV).