[1] In this paper a set of frequency domain (500 Hz to 1 MHz) experimental data on electrical and magnetic parameters of magnetite/silica mixtures as Martian soil simulants is presented. Complex permittivity was obtained by measuring the magnitude and phase of the electrical impedance of a capacitive cell filled with the tested material. Complex magnetic permeability was obtained by measuring the impedance of a toroid fully embedded in the mixtures. Both the permittivity and magnetic permeability exhibited an appreciable increase with the magnetite volume fraction and a complex behavior with grain size and origin. Furthermore, to assess the possibility of extending the data acquired at 1 MHz to higher frequencies (tens to hundreds of MHz), some comparisons were made between these data and Time Domain Reflectometry measurements. Finally, the attenuation versus magnetite volume fraction and frequency (in a band consistent with the MARSIS and SHARAD sounders) was computed for various types of magnetite/silica mixtures. The results indicate that in a dry soil which contains a significant fraction of magnetic material both the wave velocity and the attenuation are a combination of different factors, including the dimension, shape, and origin of the magnetic material.

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In this work, the effects of magnetic inclusions in a Mars-like soil are considered with reference to the electromagnetic propagation features of ground-penetrating radars (GPRs). Low-frequency and time-domain techniques, using L-C-R meters and TDR instruments, respectively, are implemented in laboratory experimental set-ups in order to evaluate complex permittivity and permeability and wave velocity for different scenarios of a dielectric background medium (silica) with magnetic inclusions (magnetite). Attenuation and maximum detection ranges have also been evaluated by taking into account a realistic GPR environment, which includes the transmitting/receiving antenna performance and the complex structure of the subsurface. The analysis and the interpretation of these results shed new light on the significant influence of magnetic inclusions on the performance of Martian orbiting and rover-driven GPRs.

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In this work, an extensive theoretical and experimental analysis has been carried out on the main factors that affect the accurate evaluation of dielectric properties using time domain reflectometry (TDR). Dielectric constant measurements have been performed under different experimental conditions for various types of materials having a wide range of permittivity values. Interpretation of the results on the basis of the transmission-line theory emphasizes the importance of a suitable\ud calibration procedure that takes into account several critical aspects, some of which seem to have been disregarded or underestimated in the literature. Qualitative and quantitative information is given on the kind of corrections needed in order to significantly improve the reliability of the TDR technique for permittivity measurements

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