Near-field is only a few wavelengths away when the antenna itself is a half wavelength in dimension. Otherwise you would calculate the size of the near field as a function of the physical dimension of the antenna and the wavelength: r2 = 2d^2/λ.

E.g. The radiating near field of a 2.4GHz antenna about 8 meters long would extend about 1km.

[1] - https://www.giangrandi.org/electronics/anttool/regions.shtml