Permittivity variations of the dust, ice, and vacuum mixture for corresponding variations in composition. The ice fraction correspond to a mixture of 73% H₂O ice (mass fraction), 14% CO₂ ice, and 15% CO ice with an effective permittivity equal to 2.7. The dust fraction is a mixture of 68% of organics (mass fraction) and 32% silicates for an effective permittivity equal to 2.6. The orange arrow corresponds to a variation in the density and constant composition and D/I (case a), the red arrow to a variation in the D/I and constant porosity and composition (case b), and the blue arrow to the same dust fraction, but desiccated or ice enriched.