An Investigation of the Extent of the Fresnel Region of Aperture Antennas with Attention to Superdirectivity

Abstract

This technical note describes the principles governing superdirective antennas and the factors limiting their realization. A criterion for determining the minimum distance to the far field of aperture antennas, including superdirective antennas, is presented. Under this condition it is shown that, at least for the marginally superdirective case, such antennas do not exhibit large fresnel regions as compared with minimum distance to the far field in a given direction. Under this criterion it is shown that for the uniform distribution, the antenna pattern near nulls requires a large distance to converge to the far field form. This work has applications in determining antenna test range requirements. Canada.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1989
Accession Number
ADA217518

Entities

People

  • Shawn Charland

Organizations

  • Defence Research and Development Canada

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Classification
  • Delta Functions
  • Diffraction
  • Electric Fields
  • Electromagnetic Fields
  • Equations
  • Evanescent Waves
  • Far Field
  • Fresnel Zones
  • Geometry
  • Magnetic Fields
  • Near Field
  • Radiation Patterns
  • Radiation Resistance
  • Security
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Phased Array Antenna Design.
  • Systems Analysis and Design