2. Physical analysis of wave absorption

This paragraph attempts to clarify the links between the concepts of attenuation and power dissipation of waves propagated in an infinitely extended absorbing medium.

The macroscopic aspect of the problem, restricted to calculating the power dissipated in a sample of the medium, is discussed first, along with composite absorbing media.

Microscopic properties of electrical conduction and energy dissipation by dipolar absorption are then discussed.