To estimate the electromagnetic field circumstance of the particle-shaped material in high frequency electromagnetic field application, the penetration scale length is shown in this paper by means of micro-sized calculation model, in which the eddy current and displacement current is considered and finite element method based on j omega method is used. From the calculation results, the following items are introduced. The eddy current, which is induced by external magnetic field, plays an important role, when electromagnetic field is applied to the particle-shaped materials in high-frequency. It is important that the electromagnetic field is in the high frequency domain where the side wave occurs, in order that the electromagnetic field is transmitted deeply into the particle-shaped materials. When the electrical conductivity of the particle substance of the particle-shaped materials varies, the eddy current distribution within the particle is different and the estimated penetration scale length has a peak value. In the high electrical conductivity, the eddy current has a clean circle within the particle, which flows around the external magnetic field direction. High Joule energy consumption is obtained. In the electrical conductivity at which the penetration scale length has a peak value, the eddy current flows in one-sided within the particle and small Joule energy consumption is obtained. In the low electrical conductivity, the eddy current flows in the same direction within all area of the particle, and high Joule energy consumption is obtained. The particle begins to behave like a dielectric and then the continuity of eddy current is not formed.
