Accession Number : AD0670830

Title :   THEORETICAL AND EXPERIMENTAL INVESTIGATION OF FOCAL PLANE ADAPTIVE ANTENNA TECHNIQUES.

Descriptive Note : Final rept. 1 Apr 67-31 Mar 68,

Corporate Author : ADVANCED TECHNOLOGY CORP TIMONIUM MD

Personal Author(s) : Cohn,Marvin ; Littlepage,Robert S.

Report Date : APR 1968

Pagination or Media Count : 81

Abstract : A scalar analysis was performed to determine the field structure in the focal region of apertures focused in their near field (f/D<1). Solutions are given for plane waves at normal incidence, and several selected angles of arrival. The results indicate a substantial variation from the Fraunhofer far field patterns. Because it is a scalar approach, it is limited to large apertures (D>> wavelength) and small diffraction angles. An experiment was designed to complement the analysis. The qualitative agreement is very good. Sources of experimental error have been found which account for the quantitative variations. A technique for determining the field structure in the focal region, due to a reasonably arbitrary distribution in the aperture plane, is given. It consists of the superposition of an ensemble of plane waves, whose amplitude, relative phase, and angle of arrival are determined by the aperture plane distribution. (Author)

Descriptors :   (*ANTENNA APERTURES, ANTENNA RADIATION PATTERNS), ANTENNAS, ADAPTIVE SYSTEMS, DIFFRACTION, ANGLE OF ARRIVAL, FOCUSING, ELECTROMAGNETIC FIELDS, PROPAGATION, INTEGRALS, NUMERICAL ANALYSIS

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE