Analysis of the Loading Effect of Faulty LNAs on Embedded Element Patterns in the Murchison Widefield Array

A number of natural phenomena occurring at the Western Australian site of the Square Kilometre Array (SKA), such as lightning or whirlwinds, can cause damage to electronic parts of antenna array elements. We consider an SKA precursor, the Murchison Widefield Array (MWA), in order to evaluate the consequences of faulty low-noise amplifiers in an array. Using network analysis methods, we predict exactly the field patterns of each array element under changing loading conditions. The values of load impedances used for MWA field calculations were based on measured data. It was observed that the tile pattern of MWA is robust to occasional low-noise amplifier damage. The ability to predict the embedded element patterns without the need to repeat numerical simulations is especially useful for such large-scale projects as the SKA.