Interaction of Microwave Magnetic Field With Materials

Microwave is an electromagnetic wave and consists of the electric and the magnetic fields.The microwave electric field interacts with dielectric materials and heat is generated due to the dielectric loss,which is a major mechanism of microwave heating of water.Microwave magnetic field interaction with materials has to be discussed in terms of two different mechanisms.The first class is the induction current generation in（mainly）metallic materials,which gives rise the Joule heat,although the penetration distance into metals are limited within a microns or less.In this article,a characteristic application of microwave induction heating of metal thin film is presented.The second class is the microwave interaction with the ferro（or ferri）magnetic materials.Effect of ferromagnetic resonance（FMR）is taken into consideration as the fundamental heating mechanism of the ferro-magnetic materials.The FMR heating behavior of Fe3O4 is presented.Discussion is made for the phenomena observed in the experiments.