The zone within a fraction of a wavelength from a transmitting antenna element. In this region, the electric and magnetic fields are distinct and do not propagate as a transverse electromagnetic wave, meaning their strength drops off extremely rapidly with distance. Engineers use this localized energy for short-range communication technologies without causing distant interference.
You have to hold the badge directly against the reader because it relies on near field coupling to power the chip.
Also heard as
- reactive near field
Do not mix it up with
- Far field: The near field is the non-radiating zone right next to the antenna, while the far field is where the signal actually propagates outward as a radio wave.
Related terms
Far field
The region surrounding an antenna where the electromagnetic field behaves as a predictable plane wave.
RFID
Radio-frequency identification, a system that uses electromagnetic fields to track tags.
Radio-frequency identification
A wireless tracking technology that uses electromagnetic fields to automatically identify and read tags attached to objects.