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In optics, the Fraunhofer diffraction equation is used to model the diffraction of waves when plane waves are incident on a diffracting object, and the diffraction pattern is viewed at a sufficiently long distance (a distance satisfying Fraunhofer condition) from the object (in the far-field region), and also when it is viewed at the focal plane of an imaging lens.
In optics, the Fraunhofer diffraction equation is used to model the diffraction of waves when the diffraction pattern is viewed at a long distance from the diffracting object, and also when it is viewed at the focal plane of an imaging lens. [1] [2]
The Fraunhofer distance, named after Joseph von Fraunhofer, is the value of: d = 2 D 2 λ , {\displaystyle d={{2D^{2}} \over {\lambda }},} where D is the largest dimension of the radiator (in the case of a magnetic loop antenna , the diameter ) and λ {\displaystyle {\lambda }} is the wavelength of the radio wave .
In the study of diffraction and antenna design, the near field is that part of the radiated field that is below distances shorter than the Fraunhofer distance, [1] which is given by = from the source of the diffracting edge or antenna of longitude or diameter D.
The result is the Fraunhofer approximation, which is only valid very far away from the object + + Depending on the size of the diffraction object, the distance to the object and the wavelength of the wave, the Fresnel approximation, the Fraunhofer approximation or neither approximation may be valid. As the distance between the measured point of ...
The intensity profile can be calculated using the Fraunhofer diffraction equation as ... (Fraunhofer diffraction), that is, at a distance much larger than the width ...
Fraunhofer diffraction returns then to be an asymptotic case that applies only when the input/output propagation distance is large enough to consider the quadratic phase term, within the Fresnel diffraction integral, negligible irrespectively to the actual curvature of the wavefront at the observation point. [5]
In contrast the diffraction pattern in the far field region is given by the Fraunhofer diffraction equation. The near field can be specified by the Fresnel number, F, of the optical arrangement. When the diffracted wave is considered to be in the Fraunhofer field. However, the validity of the Fresnel diffraction integral is deduced by the ...