Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In the field of antenna design the term ''radiation pattern'' most commonly refers to the directional (angular) dependence of radiation from the antenna or other source (synonyms: antenna pattern, far-field pattern). Particularly in the fields of fiber optics, lasers, and integrated optics, the term radiation pattern, or near-field radiation pattern, may also be used as a synonym for the near-field pattern or Fresnel pattern. This refers to the positional dependence of the electromagnetic field in the near-field, or Fresnel region of the source. The near-field pattern is most commonly defined over a plane placed in front of the source, or over a cylindrical or spherical surface enclosing it.