MICROWAVE POWER ABSORPTION CHARACTERISTICS OF IRON OXIDES

摘要

The microwave power absorption characteristics of iron oxides, including Fe_2O_3, Fe_3O_4 and Fe_(0.925)O, have been studied by determining dielectric loss and magnetic loss distributions in 0.05-m-thick oxide slabs irradiated with 1.2-kW, 2.45-GHz microwaves. The results reveal that the dielectric loss is the main factor contributing to microwave absorption in Fe_2O_3 and Fe_(0.925)O, while the magnetic loss dominates the power absorption in Fe_3O_4 below its Curie point. Uneven power distributions are observed in the slabs and this phenomenon becomes even worse at high temperatures at which the permittivity increases significantly. Quantification of power absorption in the oxides is of great importance for efficient and uniform microwave heating.