Near-field effect of the microwaves power applicators investigated for liquid processing applications

Microwave heating of high loss liquids was performed using two applicator types, a coaxial configuration and a pair of rectangular slot antennas. The temperature profiles in the as-heated liquid samples were investigated in real time. The dielectric properties of the samples were measured over a broad band of frequencies at the same temperature value as the highest one reached in the temperature profile. The heating depth in the liquid was compared to the dielectric loss for different samples. These investigations were performed for surface microwave processing in liquid mixtures (living tissues), for extraction applications and medical thermal treatments.