Dielectric Properties investigation of Commercial Milk Powder at 2.45 GHz

Abstract

Milk powder can be contaminated by pathogens, leading to major health concerns. dielectric properties can detect and help in treatment of such contaminations.  Hence, dielectric properties relevant to dielectric heating were investigated at 2.45 GHz which is a common ISM frequency. These properties (Dielectric constant and dielectric loss factor) were determined using cavity perturbation method with the help of a vector network analyzer (VNA) in moisture and temperature range 3 – 17% (w.b) and 15-65 ℃ respectively.  Present studies showed that dielectric constant and loss factor increased with temperature and moisture content. Calculated penetration depth based on these properties decreased with moisture and temperature. A 2^nd order regression equation was generated to know dielectric properties values at 2.45 GHz at desired moisture content and temperature, for which R² is 0.9947.