Abstract

Mutual coupling (MC) among SKA -Low’s log-periodic antennas introduces narrowband resonances that imprint sharp spectral structure on the embedded element patterns (EEPs). These features disrupt the spectral smoothness required by time-gating foreground-removal techniques, allowing bright astrophysical emission to leak into and obscure the faint 21-cm cosmological signal. Full-wave, end-to-end simulations show that MC substantially increases spectral complexity, and that effective foreground suppression therefore requires station-beam models with high spectral resolution and far-field accuracy at the level of 4–5 significant digits, well beyond the assumptions of many current EoR pipelines.

In this talk, we leverage the formal equivalence between phased-array beamforming and interferometric imaging to perform real-time, wideband, wide-field, direction-dependent calibration directly on the incoming voltage streams, through reconstructing element patterns through inversion of stacked Jones matrices. We demonstrate how station-level processing can partially compensate severe MC effects before quantify the required EEP accuracy for interferometric MC mitigation. This work links antenna theory with radio-interferometric calibration, outlining a practical path toward robust, wideband mutual-coupling suppression for 21-cm EoR experiments.