MEASUREMENT OF PARAMETERS OF PENCIL-BEAM ANTENNAS IN THE NEAR ZONE,

Abstract : The paper investigates the feasibility of near zone measurements of the side lobes and amplification coefficients of highly directional parabolic antennas whose diagrams have a width on the order of a few minutes. During the comparison of the directivity diagrams measured in the far and near zones the authors arrived at an expression which, as they found out after submitting their paper for publication, is for all practical purposes identical with the expression published earlier by J. J. Stangel and W. M. Yarnell. They also outline a method for the measurement of antenna amplifications using cosmic sources whose dimensions exceed the width of the main lobe (whose size was determined by preliminary measurements within the near zone). These methods are illustrated by the results of measurements (using the Moon as the source) of the amplification of the antenna of the 22-meter RT-22 radiotelescope carried out by FIAN in the millimeter wave band.