EN-4
calculate the magnetic field for the electric
field value. This meter can display the
calculated magnetic field strength.
4.2 Power density (S)
Power per unit area normal to the direction
of propagation, usually expressed in units
of watts per square meter (W/m
2
) or, for
convenience, units such as mill watts per
square centimeter (mW/cm
2
)
4.3 The characteristic of electromagnetic
fields
Electromagnetic fields propagate as
waves and travel at the speed of light (C).
The wavelength is proportional to the
frequency.
λ
(wavelength) = C (speed of light) /
f (frequency)
If the distance to the field source is less
than three wavelengths, then we are
usually in the near field. If the distance is
more than three wavelengths, the far-field
conditions usually hold.
In near field conditions, the magnetic field
value cannot be calculated from the
electric field value. This meter is designed
for reliable far field measurements only.
