Estimating Soil Electrical Parameters in the Canadian High Arctic From Impedance Measurements of the MIST Antenna Above the Surface

Abstract The MIST experiment aims to detect the cosmological 21‐cm signal through sky observations at 25–125 MHz using a wide‐beam antenna. The antenna is mounted above the soil and the beam characteristics are highly dependent on the soil's electrical properties. Accurate models for the beam obtained from electromagnetic simulations are crucial for detecting the 21‐cm signal. Determining the soil properties to inform the beam simulations is therefore a very high priority for MIST. Here we report the first electrical characterization of the MIST observation site in the Canadian High Arctic, which was conducted in July 2022. The electrical parameters were estimated using impedance measurements of the instrument's antenna, which is a very advantageous approach for MIST. Our best‐fit soil model is consistent with a thawed active layer underlain by permafrost, and the parameters were estimated with a precision close to the requirements for the detection of the cosmological 21‐cm signal.