Real-Time Wideband Widefield Mutual Coupling Compensation for SKA-Low

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• Dr. Oscar O'Hara (Cavendish Astrophysics)
• Tuesday 25 November 2025, 11:15-12:00
• Coffee area, Battcock Centre.

If you have a question about this talk, please contact Charles Walker.

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.

This talk is part of the Hills Coffee Talks series.

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