Accession Number : AD0622407

Title :   UNIFORM EVALUATION OF RADIATION FIELDS.

Descriptive Note : Scientific rept.,

Corporate Author : RHODE ISLAND UNIV KINGSTON

Personal Author(s) : Kane,Julius ; Cretella,John P.

Report Date : JUN 1965

Pagination or Media Count : 36

Abstract : Solutions to many problems involving electromagnetic wave propagation are often given as contour integrals in the wave number plane which unfortunately cannot be readily evaluated. By employing the method of steepest descents, asymptotic expansions can be found to determine the far fields, but these furnish little information on the transition region from the source to the Fraunhofer region. In this work, a procedure is introduced which facilitates the evaluation of Fourier-type integrals in the Fresnel zone. The present method decomposes the integral representation into a standard form: a linear combination of two Hankel functions of the first kind, trigonometric functions. With this result, an exact representation which is uniformly valid from the near zone to the far field is obtained. The useful domain also includes such regions as the critical angles in real space, corresponding to the shadow boundaries associated with the pole contributions.

Descriptors :   (*FIELD THEORY, DIFFRACTION), (*INTEGRAL TRANSFORMS, FIELD THEORY), INTEGRALS, SPECIAL FUNCTIONS(MATHEMATICAL), TRIGONOMETRY, FOURIER ANALYSIS, ELECTROMAGNETIC RADIATION, PROPAGATION

Distribution Statement : APPROVED FOR PUBLIC RELEASE