Cross-validation of the EM simulations of SKALA4.1 with HARP

Simulations of SKA1 LOW data are important for driving the development of SDP pipelines and for the analysis of SKA1 data for a number of science use cases (eg EoR) that are very sensitive to the spatial and frequency behaviour of the LOW station beam. 

Improving our tooling for this will enable more sophisticated tests to be carried out before SKA data is available and, in the longer term, analysis of SKA data products against simulations which is anticipated to greatly help improve understanding of how to optimise the use of the telescope. 

Results and detail can be found on the confluence page (https://confluence.skatelescope.org/display/SE/SPO-2066+%3A+Validate+HARP+simulations+of+SKALA4.1). The comparison of isolated SKALA4.1 antenna was performed using two models. A model used in the FEKO simulation provided by David Ung (model_v1) and simplified has roughly 2.5x fewer mesh elements and basis functions. The impedance and the radiation pattern using model_v1 has very good agreement with FEKO simulations. The simplified model has a good agreement for higher frequencies. A comparison of two-element configuration, small 3x3 regular array, and full station in Vogel Layout (256 elements) compared to FEKO was carried out. All configurations show good agreement with the FEKO simulation on a range of tested frequencies. The AAVS2 was not tested as the minimum distance between antennas is not suitable for HARP, and further work is needed.