Fresnel region fields produced by circular loops and annular slots antennas

Guillermo Gonzalez, Manuel A. Huerta

Research output: Contribution to journalArticle

Abstract

Exact closed-form expressions for the Fresnel region electric and magnetic fields of circular loop and annular slot antennas are given in terms of the functions en(σ,γ)=(1/2π)02π cos(nΦ) sin[σ(1-2γ cosΦ)1/2] dΦ and fn(σ ,γ)=(1/2π)02π cos(nΦ) cos[σ(1-2γ cosΦ) 1/2] dΦ, where - ∞ < σ < ∞ and 0 ≤ γ ≤ 1/2. For a circular loope antenna with a constant current distribution the Fresnel region fields are obtained in terms of the functions qn (σ,γ)=fn (σ,γ)+ie n(σ,γ), with n =0,1, and 2, and for a cosine current distribution the Fresnel region fields are obtained in terms of the functions qn(σ,γ), with n =0,1,2,3, and 4. The magnetic field of an annular slot antenna excited by a constant voltage is expressed exactly in terms of an infinite series involving the functions qn (σ,γ). The Fresnel region magnetic field of the annular slot antenna is simply given in terms of q1(σ,γ). The functions qn(σ,γ) permitted a simple evaluation of the electric and magnetic field strength in the Fresnel region. The functions q n(σ,γ) for n =0,1,2,3, and 4 are tabulated for values of σ=0.5, 1, 2, 5, 10, 25, and 50 and values of γ from 0.01 to 0.5.

Original languageEnglish (US)
Pages (from-to)3500-3504
Number of pages5
JournalJournal of Applied Physics
Volume44
Issue number8
DOIs
StatePublished - Dec 1 1973

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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