The far field, or Fraunhofer region, begins at a specific distance from a transmitting antenna where the angular distribution of the radiated energy becomes independent of the distance. In this zone, the electric and magnetic fields are orthogonal to each other and to the direction of propagation. Antenna gain and radiation patterns are almost exclusively measured in the far field.
We need to move the test rig back another ten meters to ensure we're taking measurements in the far field.
Also heard as
- Fraunhofer region
Do not mix it up with
- Near field: Near field is the region immediately around the antenna where fields are complex and non-radiating; far field is where the stable radio wave propagates.
Related terms
Near field
The electromagnetic region immediately surrounding an antenna where fields are not yet fully formed into a radiating wave.
Directivity
A measure of how concentrated an antenna's radiated power is in a specific direction.
Feedpoint
The physical location on an antenna where the transmission line connects to transfer radio frequency power.