Electromagnetic Characterization of Volcanic Ash

An open-ended coaxial probe is designed for making permittivity measurements on volcanic ash. Reference liquids such as water and methanol are used for calibrating the probe, whose input admittance is related to the complex permittivity by Marcuvitz integral. The reflection coefficient of the probe in the presence of volcanic ash samples from Etna volcano, Italy, is measured from 1 to 15 GHz and subsequently processed to retrieve the complex permittivity of the material under test.