A Solution to the Frequency-Independent Antenna Problem

Abstract

A solution of Maxwell's equations is obtained for an antenna consisting of an infinite number of equally spaced wires in the form of coplanar equiangular spirals. Radiation amplitude patterns obtained from this solution agree closely with measurements on two-element spiral antennas. The phase pattern shows the approximate validity of a phase center at a distance behind the antenna which decreases with the tightness of the spiral. The current distribution shows increased attenuation with increase in the tightness of the spiral, thus showing how the frequency-independent mode depends of the curvature. A remarkable feature of the solution is that the current consists of an inward traveling wave at infinity when the antenna is excited in that sense which produces an outward wave at the center.

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Document Details

Document Type
Technical Report
Publication Date
Jan 08, 1962
Accession Number
AD0427641

Entities

People

  • B. R. Cheo
  • V. H. Rumsey
  • W. J. Welch

Organizations

  • University of California, Berkeley

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms

DTIC Thesaurus Topics

  • Air Force
  • Antennas
  • Bessel Functions
  • Contracts
  • Current Density
  • Electric Fields
  • Equations
  • Far Field
  • Frequency
  • Government Procurement
  • Governments
  • Phase Velocity
  • Radiation
  • Radiation Patterns
  • Spiral Antennas
  • Traveling Waves
  • Waves

Fields of Study

  • Physics

Readers

  • Electromagnetic Wave Scattering and Antenna Radiation Engineering

Technology Areas

  • Space