4. Lines with losses

4.1 Origin of losses

• Metal losses

  These losses are due to the linear resistance R, characteristic of the conductor. This linear resistance R is generally not constant with frequency, due to the skin effect: as frequency increases, the current tends to flow at the periphery of the conductor, resulting in a reduction in the conductor's effective cross-section, and therefore an increase in its resistance.

  By noting σ the conductivity of the conductor, we then show that everything happens as if the current flows at the periphery of the conductor in a "skin thickness" e whose value is equal to :