Accession Number : ADA189543

Title :   Modification of Parabolic Dish Antenna Pattern Using Two Symmetrically Placed Circular Flat Plates.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s) : Thorpe, Glen C

PDF Url : ADA189543

Report Date : Dec 1987

Pagination or Media Count : 106

Abstract : This study aims to formulate a method of predicting the far field pattern of a parabolic dish antenna with two moveable flat plates mounted symmetrically on either side of the feed horn. The approach taken has been to first analyze the radiation pattern of the antenna with the disks at certain heights out from the surface of the dish. To do this the near-field radiation in amplitude and phase was measured over a plane surface in the near-field and the values were then transformed into the far field using a Fast Fourier Transform. Far field pattern values of the antenna were directly measured for each setting of the plates. The results obtained from the Fast Fourier Transform of the near field data were in good agreement with the values obtained by measurement. Finally, an approximate model of the antenna was developed and implemented as a computer program. This model, while relatively unsophisticated, provided some insights into the changes in the near field phase distribution caused by the moveable circular flat plates.

Descriptors :   *ANTENNA FEEDS, *ANTENNA RADIATION PATTERNS, *COMPUTER PROGRAMS, *DISKS, *FAR FIELD, *FLAT PLATE MODELS, *NEAR FIELD, *PARABOLIC ANTENNAS, CIRCULAR, HORN ANTENNAS, MODELS, PARABOLAS, PATTERNS, PLANE GEOMETRY, PLATES, RADIATION, RADIATION PATTERNS, SETTING(ADJUSTING), SURFACES, THESES

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE