Absorption of Microwave Energy by a Spherical Nonmagnetic Metal Particle

A single particle model is used to provide simple physical insight into the absorption of microwave energy by nonmagnetic metal powders. For this, Mie theory is applied to the microwave heating of a highly conductive spherical particle of micron size. The frequency of the electromagnetic wave is 2.45GHz. Energy absorption by the highly conductive particle arises from Joule heating by eddy currents which occur as a result of the magnetic component of the electromagnetic wave. Since the electric field component is screened out by conduction electrons, the particle ineffectively couples with this component. The necessary condition for complete separation of dielectric and magnetic losses is provided. Scaling of the induced current with particle size is considered. The region, where the single particle model is valid, is outlined. (C) 2009 The Japan Society of Applied Physics