Mutual Impedance matrix extraction from embedded element patterns of the Murchison Widefield Array

Low frequency aperture arrays for radio astronomy, one of which is the Murchison Widefield Array, are at the forefront of modern radio astronomy aiming to expand our knowledge on the universe by low-frequency science. Due to the high density of aperture arrays at the low end of the operating spectrum, strong mutual coupling is a concern. While the embedded element patterns of deployed prototypes can and have been measured using unmanned aerial vehicles, traditional direct measurements of the mutual impedance matrix are not feasible. This paper addresses the issue using a recently introduced method of mutual impedance matrix extraction from simulated array embedded element patterns. Through an iterative optimisation process, mutual impedance matrices at five frequency points within the 70-300 MHz range were extracted with a very low relative error, confirming the robustness of the method.