Near-field region

In telecommunication, the term near-field region has the following meanings:

1. The close-in region of an antenna wherein the angular field distribution is dependent upon distance from the antenna. Synonyms near field, near zone.

2. In optical fiber communications, the region close to a source or aperture.

Note: The diffraction pattern in this region typically differs significantly from that observed at infinity and varies with distance from the source.

Source: from Federal Standard 1037C and from MIL-STD-188