# Dictionary:Far-field

Field remote from the source. Spherical waves involve terms that decrease as both 1/*r* and 1/*r*^{2}, where *r* is distance from the source (see Sheriff and Geldart, 1995, 48); far-field implies that the terms that depend on 1/*r*^{2} are unimportant. The far-field represents radiated energy and implies that *r*≫λ, where λ=wavelength. Compare *near-field*.