Scanning performance of SKA-low sparse array configurations incorporating realistic element patterns and sky noise contributions

Broadband antenna arrays have become widely used for high sensitivity imaging application such as radio astronomy and are envisaged for the low frequency SKA telescope which will contain approximately 500,000 antennas in phase 1 alone operating over the 70 MHz to 450 MHz band. For wide angle beamforming a crucial design aspect is the antenna element radiation pattern which directly affects the performance of the instrument particularly at wide scan angles off zenith. These effects have not been studied in detail, particularly for sparse and irregular geometries and are therefore crucial for analyzing performance trade-offs as well as for understanding the underlying assumptions made for instrument calibration. This paper provides a brief study of the various tradeoffs regarding the antenna element radiation pattern and irregular array geometries which can be utilized to optimize the performance. For this purpose the far-field station patterns will be convolved with the sky brightness temperature distribution from the Haslam 408 MHz survey which is then scaled to observations in the SKA-low frequency band.