Intermediate-field region

Intermediate-field region: For an antenna, the transition region--lying between the near-field region and the far-field region--in which the field strength of an electromagnetic wave is dependent upon the inverse distance, inverse square of the distance, and the inverse cube of the distance from the antenna.

Note: For an antenna that is small compared to the wavelength in question, the intermediate-field region is considered to exist at all distances between 0.1 wavelength and 1.0 wavelength from the antenna. Synonyms: intermediate field, intermediate zone, transition zone.

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