Three different kinds of Fraunhofer approximations: 1. Propagation of the field amplitude


  • William H. Carter


The Fraunhofer approximations as usually used in diffraction, radiation, and antenna theories have some important and very useful differences. This paper examines three kinds of Fraunhofer approximations in applications to the propagation of a scalar field amplitude from sources to detectors. Each of the three approximations is examined to make clear the differences in their conditions for validity and mathematical structure. Some differences in their applications are also discussed.