70977

Generalisation

Although we have studied the case of normal incidence only, the generał picture we have

derived is considered to the applicable to a wide rangę of practical cases.

Thus whenever we have a metallic boundary supporting a magnetic field, we will always assume the magnetic field is supported by a total surface current density K equal

in magnitude but at right angles in direction to the tangential component Htof H, and

that the power dissipated per unit area of surface is

Wa=

1

21 Ht | 2Rs (9.21)

where

Rs=

1

6 o

(9.22)

and

6=

s

2

Ułpo • (9.23)

We will find this ability to calculate the power lost, due to skin effect, per unit surface area of a boundary, useful in the determination of the attenation of waves in both coaxial

lines and in hollow waveguides