Wideband measurement of dielectric properties of powder materials. Developing an experimental set-up

Knowledge of dielectric properties of materials is at the basis of the application of microwaves as non-destructive and non-invasive tools for quality evaluation of foods. In this contribution, the development of an experimental framework to characterize on a wide frequency range dielectric properties of powder food is proposed. The used methodologies include the open-ended coaxial probe technique and a waveguide system, the former being inherently a wideband technique but suffering from the typology of material under test, the latter being a medium-band technique. Examples of measured materials are reported, with particular reference to the measurement of sugar.