Research on the interception power of finite object in plane wave

Scattering field is usually associated with incident field. When we mention scattering field, it simultaneously means an existence of incident field, and the complete field is the superposifion of them. However, if we ask what´s the relationship between the scattering power and incident power of a finite object, it may not be easy to answer. In this paper, some new concepts, such as the theoretical interception power and medium factor, are introduced to study the relationship between the scattering power and incident power of finite object. The results can be used to calculate the emissivity of finite objects.